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FLAC/stream_encoder.h: stream encoder interface
[FLAC/_encoder.h: encoder interfaces]

Detailed Description

This module contains the functions which implement the stream encoder.

The stream encoder can encode to native FLAC, and optionally Ogg FLAC (check FLAC_API_SUPPORTS_OGG_FLAC) streams and files.

The basic usage of this encoder is as follows:

In more detail, the stream encoder functions similarly to the stream decoder , but has fewer callbacks and more options. Typically the client will create a new instance by calling FLAC__stream_encoder_new(), then set the necessary parameters with FLAC__stream_encoder_set_*(), and initialize it by calling one of the FLAC__stream_encoder_init_*() functions.

Unlike the decoders, the stream encoder has many options that can affect the speed and compression ratio. When setting these parameters you should have some basic knowledge of the format (see the user-level documentation or the formal description). The FLAC__stream_encoder_set_*() functions themselves do not validate the values as many are interdependent. The FLAC__stream_encoder_init_*() functions will do this, so make sure to pay attention to the state returned by FLAC__stream_encoder_init_*() to make sure that it is FLAC__STREAM_ENCODER_INIT_STATUS_OK. Any parameters that are not set before FLAC__stream_encoder_init_*() will take on the defaults from the constructor.

There are three initialization functions for native FLAC, one for setting up the encoder to encode FLAC data to the client via callbacks, and two for encoding directly to a file.

For encoding via callbacks, use FLAC__stream_encoder_init_stream(). You must also supply a write callback which will be called anytime there is raw encoded data to write. If the client can seek the output it is best to also supply seek and tell callbacks, as this allows the encoder to go back after encoding is finished to write back information that was collected while encoding, like seek point offsets, frame sizes, etc.

For encoding directly to a file, use FLAC__stream_encoder_init_FILE() or FLAC__stream_encoder_init_file(). Then you must only supply a filename or open FILE*; the encoder will handle all the callbacks internally. You may also supply a progress callback for periodic notification of the encoding progress.

There are three similarly-named init functions for encoding to Ogg FLAC streams. Check FLAC_API_SUPPORTS_OGG_FLAC to find out if the library has been built with Ogg support.

The call to FLAC__stream_encoder_init_*() currently will also immediately call the write callback several times, once with the fLaC signature, and once for each encoded metadata block. Note that for Ogg FLAC encoding you will usually get at least twice the number of callbacks than with native FLAC, one for the Ogg page header and one for the page body.

After initializing the instance, the client may feed audio data to the encoder in one of two ways:

Note that for either process call, each sample in the buffers should be a signed integer, right-justified to the resolution set by FLAC__stream_encoder_set_bits_per_sample(). For example, if the resolution is 16 bits per sample, the samples should all be in the range [-32768,32767].

When the client is finished encoding data, it calls FLAC__stream_encoder_finish(), which causes the encoder to encode any data still in its input pipe, and call the metadata callback with the final encoding statistics. Then the instance may be deleted with FLAC__stream_encoder_delete() or initialized again to encode another stream.

For programs that write their own metadata, but that do not know the actual metadata until after encoding, it is advantageous to instruct the encoder to write a PADDING block of the correct size, so that instead of rewriting the whole stream after encoding, the program can just overwrite the PADDING block. If only the maximum size of the metadata is known, the program can write a slightly larger padding block, then split it after encoding.

Make sure you understand how lengths are calculated. All FLAC metadata blocks have a 4 byte header which contains the type and length. This length does not include the 4 bytes of the header. See the format page for the specification of metadata blocks and their lengths.

Note:
If you are writing the FLAC data to a file via callbacks, make sure it is open for update (e.g. mode "w+" for stdio streams). This is because after the first encoding pass, the encoder will try to seek back to the beginning of the stream, to the STREAMINFO block, to write some data there. (If using FLAC__stream_encoder_init*_file() or FLAC__stream_encoder_init*_FILE(), the file is managed internally.)

The "set" functions may only be called when the encoder is in the state FLAC__STREAM_ENCODER_UNINITIALIZED, i.e. after FLAC__stream_encoder_new() or FLAC__stream_encoder_finish(), but before FLAC__stream_encoder_init_*(). If this is the case they will return true, otherwise false.

FLAC__stream_encoder_finish() resets all settings to the constructor defaults.


Classes

struct  FLAC__StreamEncoder

Typedefs

typedef FLAC__StreamEncoderReadStatus(* FLAC__StreamEncoderReadCallback )(const FLAC__StreamEncoder *encoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
typedef FLAC__StreamEncoderWriteStatus(* FLAC__StreamEncoderWriteCallback )(const FLAC__StreamEncoder *encoder, const FLAC__byte buffer[], size_t bytes, unsigned samples, unsigned current_frame, void *client_data)
typedef FLAC__StreamEncoderSeekStatus(* FLAC__StreamEncoderSeekCallback )(const FLAC__StreamEncoder *encoder, FLAC__uint64 absolute_byte_offset, void *client_data)
typedef FLAC__StreamEncoderTellStatus(* FLAC__StreamEncoderTellCallback )(const FLAC__StreamEncoder *encoder, FLAC__uint64 *absolute_byte_offset, void *client_data)
typedef void(* FLAC__StreamEncoderMetadataCallback )(const FLAC__StreamEncoder *encoder, const FLAC__StreamMetadata *metadata, void *client_data)
typedef void(* FLAC__StreamEncoderProgressCallback )(const FLAC__StreamEncoder *encoder, FLAC__uint64 bytes_written, FLAC__uint64 samples_written, unsigned frames_written, unsigned total_frames_estimate, void *client_data)

Enumerations

enum  FLAC__StreamEncoderState {
  FLAC__STREAM_ENCODER_OK = 0, FLAC__STREAM_ENCODER_UNINITIALIZED, FLAC__STREAM_ENCODER_OGG_ERROR, FLAC__STREAM_ENCODER_VERIFY_DECODER_ERROR,
  FLAC__STREAM_ENCODER_VERIFY_MISMATCH_IN_AUDIO_DATA, FLAC__STREAM_ENCODER_CLIENT_ERROR, FLAC__STREAM_ENCODER_IO_ERROR, FLAC__STREAM_ENCODER_FRAMING_ERROR,
  FLAC__STREAM_ENCODER_MEMORY_ALLOCATION_ERROR
}
enum  FLAC__StreamEncoderInitStatus {
  FLAC__STREAM_ENCODER_INIT_STATUS_OK = 0, FLAC__STREAM_ENCODER_INIT_STATUS_ENCODER_ERROR, FLAC__STREAM_ENCODER_INIT_STATUS_UNSUPPORTED_CONTAINER, FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_CALLBACKS,
  FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_NUMBER_OF_CHANNELS, FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_BITS_PER_SAMPLE, FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_SAMPLE_RATE, FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_BLOCK_SIZE,
  FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_MAX_LPC_ORDER, FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_QLP_COEFF_PRECISION, FLAC__STREAM_ENCODER_INIT_STATUS_BLOCK_SIZE_TOO_SMALL_FOR_LPC_ORDER, FLAC__STREAM_ENCODER_INIT_STATUS_NOT_STREAMABLE,
  FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_METADATA, FLAC__STREAM_ENCODER_INIT_STATUS_ALREADY_INITIALIZED
}
enum  FLAC__StreamEncoderReadStatus { FLAC__STREAM_ENCODER_READ_STATUS_CONTINUE, FLAC__STREAM_ENCODER_READ_STATUS_END_OF_STREAM, FLAC__STREAM_ENCODER_READ_STATUS_ABORT, FLAC__STREAM_ENCODER_READ_STATUS_UNSUPPORTED }
enum  FLAC__StreamEncoderWriteStatus { FLAC__STREAM_ENCODER_WRITE_STATUS_OK = 0, FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR }
enum  FLAC__StreamEncoderSeekStatus { FLAC__STREAM_ENCODER_SEEK_STATUS_OK, FLAC__STREAM_ENCODER_SEEK_STATUS_ERROR, FLAC__STREAM_ENCODER_SEEK_STATUS_UNSUPPORTED }
enum  FLAC__StreamEncoderTellStatus { FLAC__STREAM_ENCODER_TELL_STATUS_OK, FLAC__STREAM_ENCODER_TELL_STATUS_ERROR, FLAC__STREAM_ENCODER_TELL_STATUS_UNSUPPORTED }

Functions

FLAC__StreamEncoder * FLAC__stream_encoder_new (void)
void FLAC__stream_encoder_delete (FLAC__StreamEncoder *encoder)
FLAC__bool FLAC__stream_encoder_set_ogg_serial_number (FLAC__StreamEncoder *encoder, long serial_number)
FLAC__bool FLAC__stream_encoder_set_verify (FLAC__StreamEncoder *encoder, FLAC__bool value)
FLAC__bool FLAC__stream_encoder_set_streamable_subset (FLAC__StreamEncoder *encoder, FLAC__bool value)
FLAC__bool FLAC__stream_encoder_set_channels (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_bits_per_sample (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_sample_rate (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_compression_level (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_blocksize (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_do_mid_side_stereo (FLAC__StreamEncoder *encoder, FLAC__bool value)
FLAC__bool FLAC__stream_encoder_set_loose_mid_side_stereo (FLAC__StreamEncoder *encoder, FLAC__bool value)
FLAC__bool FLAC__stream_encoder_set_apodization (FLAC__StreamEncoder *encoder, const char *specification)
FLAC__bool FLAC__stream_encoder_set_max_lpc_order (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_qlp_coeff_precision (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_do_qlp_coeff_prec_search (FLAC__StreamEncoder *encoder, FLAC__bool value)
FLAC__bool FLAC__stream_encoder_set_do_escape_coding (FLAC__StreamEncoder *encoder, FLAC__bool value)
FLAC__bool FLAC__stream_encoder_set_do_exhaustive_model_search (FLAC__StreamEncoder *encoder, FLAC__bool value)
FLAC__bool FLAC__stream_encoder_set_min_residual_partition_order (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_max_residual_partition_order (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_rice_parameter_search_dist (FLAC__StreamEncoder *encoder, unsigned value)
FLAC__bool FLAC__stream_encoder_set_total_samples_estimate (FLAC__StreamEncoder *encoder, FLAC__uint64 value)
FLAC__bool FLAC__stream_encoder_set_metadata (FLAC__StreamEncoder *encoder, FLAC__StreamMetadata **metadata, unsigned num_blocks)
FLAC__StreamEncoderState FLAC__stream_encoder_get_state (const FLAC__StreamEncoder *encoder)
FLAC__StreamDecoderState FLAC__stream_encoder_get_verify_decoder_state (const FLAC__StreamEncoder *encoder)
const char * FLAC__stream_encoder_get_resolved_state_string (const FLAC__StreamEncoder *encoder)
void FLAC__stream_encoder_get_verify_decoder_error_stats (const FLAC__StreamEncoder *encoder, FLAC__uint64 *absolute_sample, unsigned *frame_number, unsigned *channel, unsigned *sample, FLAC__int32 *expected, FLAC__int32 *got)
FLAC__bool FLAC__stream_encoder_get_verify (const FLAC__StreamEncoder *encoder)
FLAC__bool FLAC__stream_encoder_get_streamable_subset (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_channels (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_bits_per_sample (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_sample_rate (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_blocksize (const FLAC__StreamEncoder *encoder)
FLAC__bool FLAC__stream_encoder_get_do_mid_side_stereo (const FLAC__StreamEncoder *encoder)
FLAC__bool FLAC__stream_encoder_get_loose_mid_side_stereo (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_max_lpc_order (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_qlp_coeff_precision (const FLAC__StreamEncoder *encoder)
FLAC__bool FLAC__stream_encoder_get_do_qlp_coeff_prec_search (const FLAC__StreamEncoder *encoder)
FLAC__bool FLAC__stream_encoder_get_do_escape_coding (const FLAC__StreamEncoder *encoder)
FLAC__bool FLAC__stream_encoder_get_do_exhaustive_model_search (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_min_residual_partition_order (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_max_residual_partition_order (const FLAC__StreamEncoder *encoder)
unsigned FLAC__stream_encoder_get_rice_parameter_search_dist (const FLAC__StreamEncoder *encoder)
FLAC__uint64 FLAC__stream_encoder_get_total_samples_estimate (const FLAC__StreamEncoder *encoder)
FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_stream (FLAC__StreamEncoder *encoder, FLAC__StreamEncoderWriteCallback write_callback, FLAC__StreamEncoderSeekCallback seek_callback, FLAC__StreamEncoderTellCallback tell_callback, FLAC__StreamEncoderMetadataCallback metadata_callback, void *client_data)
FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_ogg_stream (FLAC__StreamEncoder *encoder, FLAC__StreamEncoderReadCallback read_callback, FLAC__StreamEncoderWriteCallback write_callback, FLAC__StreamEncoderSeekCallback seek_callback, FLAC__StreamEncoderTellCallback tell_callback, FLAC__StreamEncoderMetadataCallback metadata_callback, void *client_data)
FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_FILE (FLAC__StreamEncoder *encoder, FILE *file, FLAC__StreamEncoderProgressCallback progress_callback, void *client_data)
FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_ogg_FILE (FLAC__StreamEncoder *encoder, FILE *file, FLAC__StreamEncoderProgressCallback progress_callback, void *client_data)
FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_file (FLAC__StreamEncoder *encoder, const char *filename, FLAC__StreamEncoderProgressCallback progress_callback, void *client_data)
FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_ogg_file (FLAC__StreamEncoder *encoder, const char *filename, FLAC__StreamEncoderProgressCallback progress_callback, void *client_data)
FLAC__bool FLAC__stream_encoder_finish (FLAC__StreamEncoder *encoder)
FLAC__bool FLAC__stream_encoder_process (FLAC__StreamEncoder *encoder, const FLAC__int32 *const buffer[], unsigned samples)
FLAC__bool FLAC__stream_encoder_process_interleaved (FLAC__StreamEncoder *encoder, const FLAC__int32 buffer[], unsigned samples)

Variables

const char *const FLAC__StreamEncoderStateString []
const char *const FLAC__StreamEncoderInitStatusString []
const char *const FLAC__StreamEncoderReadStatusString []
const char *const FLAC__StreamEncoderWriteStatusString []
const char *const FLAC__StreamEncoderSeekStatusString []
const char *const FLAC__StreamEncoderTellStatusString []

Typedef Documentation

typedef FLAC__StreamEncoderReadStatus(* FLAC__StreamEncoderReadCallback)(const FLAC__StreamEncoder *encoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
 

Signature for the read callback.

A function pointer matching this signature must be passed to FLAC__stream_encoder_init_ogg_stream() if seeking is supported. The supplied function will be called when the encoder needs to read back encoded data. This happens during the metadata callback, when the encoder has to read, modify, and rewrite the metadata (e.g. seekpoints) gathered while encoding. The address of the buffer to be filled is supplied, along with the number of bytes the buffer can hold. The callback may choose to supply less data and modify the byte count but must be careful not to overflow the buffer. The callback then returns a status code chosen from FLAC__StreamEncoderReadStatus.

Here is an example of a read callback for stdio streams: 

 FLAC__StreamEncoderReadStatus read_cb(const FLAC__StreamEncoder *encoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
 {
   FILE *file = ((MyClientData*)client_data)->file;
   if(*bytes > 0) {
     *bytes = fread(buffer, sizeof(FLAC__byte), *bytes, file);
     if(ferror(file))
       return FLAC__STREAM_ENCODER_READ_STATUS_ABORT;
     else if(*bytes == 0)
       return FLAC__STREAM_ENCODER_READ_STATUS_END_OF_STREAM;
     else
       return FLAC__STREAM_ENCODER_READ_STATUS_CONTINUE;
   }
   else
     return FLAC__STREAM_ENCODER_READ_STATUS_ABORT;
 }

Note:
In general, FLAC__StreamEncoder functions which change the state should not be called on the encoder while in the callback.
Parameters:
encoder The encoder instance calling the callback.
buffer A pointer to a location for the callee to store data to be encoded.
bytes A pointer to the size of the buffer. On entry to the callback, it contains the maximum number of bytes that may be stored in buffer. The callee must set it to the actual number of bytes stored (0 in case of error or end-of-stream) before returning.
client_data The callee's client data set through FLAC__stream_encoder_set_client_data().
Return values:
FLAC__StreamEncoderReadStatus The callee's return status.

typedef FLAC__StreamEncoderWriteStatus(* FLAC__StreamEncoderWriteCallback)(const FLAC__StreamEncoder *encoder, const FLAC__byte buffer[], size_t bytes, unsigned samples, unsigned current_frame, void *client_data)
 

Signature for the write callback.

A function pointer matching this signature must be passed to FLAC__stream_encoder_init*_stream(). The supplied function will be called by the encoder anytime there is raw encoded data ready to write. It may include metadata mixed with encoded audio frames and the data is not guaranteed to be aligned on frame or metadata block boundaries.

The only duty of the callback is to write out the bytes worth of data in buffer to the current position in the output stream. The arguments samples and current_frame are purely informational. If samples is greater than 0, then current_frame will hold the current frame number that is being written; otherwise it indicates that the write callback is being called to write metadata.

Note:
Unlike when writing to native FLAC, when writing to Ogg FLAC the write callback will be called twice when writing each audio frame; once for the page header, and once for the page body. When writing the page header, the samples argument to the write callback will be 0.

In general, FLAC__StreamEncoder functions which change the state should not be called on the encoder while in the callback.

Parameters:
encoder The encoder instance calling the callback.
buffer An array of encoded data of length bytes.
bytes The byte length of buffer.
samples The number of samples encoded by buffer. 0 has a special meaning; see above.
current_frame The number of the current frame being encoded.
client_data The callee's client data set through FLAC__stream_encoder_init_*().
Return values:
FLAC__StreamEncoderWriteStatus The callee's return status.

typedef FLAC__StreamEncoderSeekStatus(* FLAC__StreamEncoderSeekCallback)(const FLAC__StreamEncoder *encoder, FLAC__uint64 absolute_byte_offset, void *client_data)
 

Signature for the seek callback.

A function pointer matching this signature may be passed to FLAC__stream_encoder_init*_stream(). The supplied function will be called when the encoder needs to seek the output stream. The encoder will pass the absolute byte offset to seek to, 0 meaning the beginning of the stream.

Here is an example of a seek callback for stdio streams: 

 FLAC__StreamEncoderSeekStatus seek_cb(const FLAC__StreamEncoder *encoder, FLAC__uint64 absolute_byte_offset, void *client_data)
 {
   FILE *file = ((MyClientData*)client_data)->file;
   if(file == stdin)
     return FLAC__STREAM_ENCODER_SEEK_STATUS_UNSUPPORTED;
   else if(fseeko(file, (off_t)absolute_byte_offset, SEEK_SET) < 0)
     return FLAC__STREAM_ENCODER_SEEK_STATUS_ERROR;
   else
     return FLAC__STREAM_ENCODER_SEEK_STATUS_OK;
 }

Note:
In general, FLAC__StreamEncoder functions which change the state should not be called on the encoder while in the callback.
Parameters:
encoder The encoder instance calling the callback.
absolute_byte_offset The offset from the beginning of the stream to seek to.
client_data The callee's client data set through FLAC__stream_encoder_init_*().
Return values:
FLAC__StreamEncoderSeekStatus The callee's return status.

typedef FLAC__StreamEncoderTellStatus(* FLAC__StreamEncoderTellCallback)(const FLAC__StreamEncoder *encoder, FLAC__uint64 *absolute_byte_offset, void *client_data)
 

Signature for the tell callback.

A function pointer matching this signature may be passed to FLAC__stream_encoder_init*_stream(). The supplied function will be called when the encoder needs to know the current position of the output stream.

Warning:
The callback must return the true current byte offset of the output to which the encoder is writing. If you are buffering the output, make sure and take this into account. If you are writing directly to a FILE* from your write callback, ftell() is sufficient. If you are writing directly to a file descriptor from your write callback, you can use lseek(fd, SEEK_CUR, 0). The encoder may later seek back to these points to rewrite metadata after encoding.
Here is an example of a tell callback for stdio streams: 
 FLAC__StreamEncoderTellStatus tell_cb(const FLAC__StreamEncoder *encoder, FLAC__uint64 *absolute_byte_offset, void *client_data)
 {
   FILE *file = ((MyClientData*)client_data)->file;
   off_t pos;
   if(file == stdin)
     return FLAC__STREAM_ENCODER_TELL_STATUS_UNSUPPORTED;
   else if((pos = ftello(file)) < 0)
     return FLAC__STREAM_ENCODER_TELL_STATUS_ERROR;
   else {
     *absolute_byte_offset = (FLAC__uint64)pos;
     return FLAC__STREAM_ENCODER_TELL_STATUS_OK;
   }
 }

Note:
In general, FLAC__StreamEncoder functions which change the state should not be called on the encoder while in the callback.
Parameters:
encoder The encoder instance calling the callback.
absolute_byte_offset The address at which to store the current position of the output.
client_data The callee's client data set through FLAC__stream_encoder_init_*().
Return values:
FLAC__StreamEncoderTellStatus The callee's return status.

typedef void(* FLAC__StreamEncoderMetadataCallback)(const FLAC__StreamEncoder *encoder, const FLAC__StreamMetadata *metadata, void *client_data)
 

Signature for the metadata callback.

A function pointer matching this signature may be passed to FLAC__stream_encoder_init*_stream(). The supplied function will be called once at the end of encoding with the populated STREAMINFO structure. This is so the client can seek back to the beginning of the file and write the STREAMINFO block with the correct statistics after encoding (like minimum/maximum frame size and total samples).

Note:
In general, FLAC__StreamEncoder functions which change the state should not be called on the encoder while in the callback.
Parameters:
encoder The encoder instance calling the callback.
metadata The final populated STREAMINFO block.
client_data The callee's client data set through FLAC__stream_encoder_init_*().

typedef void(* FLAC__StreamEncoderProgressCallback)(const FLAC__StreamEncoder *encoder, FLAC__uint64 bytes_written, FLAC__uint64 samples_written, unsigned frames_written, unsigned total_frames_estimate, void *client_data)
 

Signature for the progress callback.

A function pointer matching this signature may be passed to FLAC__stream_encoder_init*_file() or FLAC__stream_encoder_init*_FILE(). The supplied function will be called when the encoder has finished writing a frame. The total_frames_estimate argument to the callback will be based on the value from FLAC__stream_encoder_set_total_samples_estimate().

Note:
In general, FLAC__StreamEncoder functions which change the state should not be called on the encoder while in the callback.
Parameters:
encoder The encoder instance calling the callback.
bytes_written Bytes written so far.
samples_written Samples written so far.
frames_written Frames written so far.
total_frames_estimate The estimate of the total number of frames to be written.
client_data The callee's client data set through FLAC__stream_encoder_init_*().

Enumeration Type Documentation

enum FLAC__StreamEncoderState
 

State values for a FLAC__StreamEncoder.

The encoder's state can be obtained by calling FLAC__stream_encoder_get_state().

If the encoder gets into any other state besides FLAC__STREAM_ENCODER_OK or FLAC__STREAM_ENCODER_UNINITIALIZED, it becomes invalid for encoding and must be deleted with FLAC__stream_encoder_delete().

Enumeration values:
FLAC__STREAM_ENCODER_OK  The encoder is in the normal OK state and samples can be processed.
FLAC__STREAM_ENCODER_UNINITIALIZED  The encoder is in the uninitialized state; one of the FLAC__stream_encoder_init_*() functions must be called before samples can be processed.
FLAC__STREAM_ENCODER_OGG_ERROR  An error occurred in the underlying Ogg layer.
FLAC__STREAM_ENCODER_VERIFY_DECODER_ERROR  An error occurred in the underlying verify stream decoder; check FLAC__stream_encoder_get_verify_decoder_state().
FLAC__STREAM_ENCODER_VERIFY_MISMATCH_IN_AUDIO_DATA  The verify decoder detected a mismatch between the original audio signal and the decoded audio signal.
FLAC__STREAM_ENCODER_CLIENT_ERROR  One of the callbacks returned a fatal error.
FLAC__STREAM_ENCODER_IO_ERROR  An I/O error occurred while opening/reading/writing a file. Check errno.
FLAC__STREAM_ENCODER_FRAMING_ERROR  An error occurred while writing the stream; usually, the write_callback returned an error.
FLAC__STREAM_ENCODER_MEMORY_ALLOCATION_ERROR  Memory allocation failed.

enum FLAC__StreamEncoderInitStatus
 

Possible return values for the FLAC__stream_encoder_init_*() functions.

Enumeration values:
FLAC__STREAM_ENCODER_INIT_STATUS_OK  Initialization was successful.
FLAC__STREAM_ENCODER_INIT_STATUS_ENCODER_ERROR  General failure to set up encoder; call FLAC__stream_encoder_get_state() for cause.
FLAC__STREAM_ENCODER_INIT_STATUS_UNSUPPORTED_CONTAINER  The library was not compiled with support for the given container format.
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_CALLBACKS  A required callback was not supplied.
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_NUMBER_OF_CHANNELS  The encoder has an invalid setting for number of channels.
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_BITS_PER_SAMPLE  The encoder has an invalid setting for bits-per-sample. FLAC supports 4-32 bps but the reference encoder currently supports only up to 24 bps.
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_SAMPLE_RATE  The encoder has an invalid setting for the input sample rate.
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_BLOCK_SIZE  The encoder has an invalid setting for the block size.
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_MAX_LPC_ORDER  The encoder has an invalid setting for the maximum LPC order.
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_QLP_COEFF_PRECISION  The encoder has an invalid setting for the precision of the quantized linear predictor coefficients.
FLAC__STREAM_ENCODER_INIT_STATUS_BLOCK_SIZE_TOO_SMALL_FOR_LPC_ORDER  The specified block size is less than the maximum LPC order.
FLAC__STREAM_ENCODER_INIT_STATUS_NOT_STREAMABLE  The encoder is bound to the Subset but other settings violate it.
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_METADATA  The metadata input to the encoder is invalid, in one of the following ways:
FLAC__STREAM_ENCODER_INIT_STATUS_ALREADY_INITIALIZED  FLAC__stream_encoder_init_*() was called when the encoder was already initialized, usually because FLAC__stream_encoder_finish() was not called.

enum FLAC__StreamEncoderReadStatus
 

Return values for the FLAC__StreamEncoder read callback.

Enumeration values:
FLAC__STREAM_ENCODER_READ_STATUS_CONTINUE  The read was OK and decoding can continue.
FLAC__STREAM_ENCODER_READ_STATUS_END_OF_STREAM  The read was attempted at the end of the stream.
FLAC__STREAM_ENCODER_READ_STATUS_ABORT  An unrecoverable error occurred.
FLAC__STREAM_ENCODER_READ_STATUS_UNSUPPORTED  Client does not support reading back from the output.

enum FLAC__StreamEncoderWriteStatus
 

Return values for the FLAC__StreamEncoder write callback.

Enumeration values:
FLAC__STREAM_ENCODER_WRITE_STATUS_OK  The write was OK and encoding can continue.
FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR  An unrecoverable error occurred. The encoder will return from the process call.

enum FLAC__StreamEncoderSeekStatus
 

Return values for the FLAC__StreamEncoder seek callback.

Enumeration values:
FLAC__STREAM_ENCODER_SEEK_STATUS_OK  The seek was OK and encoding can continue.
FLAC__STREAM_ENCODER_SEEK_STATUS_ERROR  An unrecoverable error occurred.
FLAC__STREAM_ENCODER_SEEK_STATUS_UNSUPPORTED  Client does not support seeking.

enum FLAC__StreamEncoderTellStatus
 

Return values for the FLAC__StreamEncoder tell callback.

Enumeration values:
FLAC__STREAM_ENCODER_TELL_STATUS_OK  The tell was OK and encoding can continue.
FLAC__STREAM_ENCODER_TELL_STATUS_ERROR  An unrecoverable error occurred.
FLAC__STREAM_ENCODER_TELL_STATUS_UNSUPPORTED  Client does not support seeking.

Function Documentation

FLAC__StreamEncoder* FLAC__stream_encoder_new (  void   ) 
 

Create a new stream encoder instance. The instance is created with default settings; see the individual FLAC__stream_encoder_set_*() functions for each setting's default.

Return values:
FLAC__StreamEncoder* NULL if there was an error allocating memory, else the new instance.

void FLAC__stream_encoder_delete (  FLAC__StreamEncoder *  encoder  ) 
 

Free an encoder instance. Deletes the object pointed to by encoder.

Parameters:
encoder A pointer to an existing encoder.
Assertions: 
 encoder != NULL

FLAC__bool FLAC__stream_encoder_set_ogg_serial_number (  FLAC__StreamEncoder *  encoder,
long  serial_number
) 
 

Set the serial number for the FLAC stream to use in the Ogg container.

Note:
This does not need to be set for native FLAC encoding.

It is recommended to set a serial number explicitly as the default of '0' may collide with other streams.

Default Value:
0
Parameters:
encoder An encoder instance to set.
serial_number See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_verify (  FLAC__StreamEncoder *  encoder,
FLAC__bool  value
) 
 

Set the "verify" flag. If true, the encoder will verify it's own encoded output by feeding it through an internal decoder and comparing the original signal against the decoded signal. If a mismatch occurs, the process call will return false. Note that this will slow the encoding process by the extra time required for decoding and comparison.

Default Value:
false
Parameters:
encoder An encoder instance to set.
value Flag value (see above).
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_streamable_subset (  FLAC__StreamEncoder *  encoder,
FLAC__bool  value
) 
 

Set the Subset flag. If true, the encoder will comply with the Subset and will check the settings during FLAC__stream_encoder_init_*() to see if all settings comply. If false, the settings may take advantage of the full range that the format allows.

Make sure you know what it entails before setting this to false.

Default Value:
true
Parameters:
encoder An encoder instance to set.
value Flag value (see above).
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_channels (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the number of channels to be encoded.

Default Value:
2
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_bits_per_sample (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the sample resolution of the input to be encoded.

Warning:
Do not feed the encoder data that is wider than the value you set here or you will generate an invalid stream.
Default Value:
16
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_sample_rate (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the sample rate (in Hz) of the input to be encoded.

Default Value:
44100
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_compression_level (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the compression level

The compression level is roughly proportional to the amount of effort the encoder expends to compress the file. A higher level usually means more computation but higher compression. The default level is suitable for most applications.

Currently the levels range from 0 (fastest, least compression) to 8 (slowest, most compression). A value larger than 8 will be treated as 8.

This function automatically calls the following other _set_ functions with appropriate values, so the client does not need to unless it specifically wants to override them:

The actual values set for each level are:
leveldo mid-side stereoloose mid-side stereoapodizationmax lpc orderqlp coeff precisionqlp coeff prec searchescape codingexhaustive model searchmin residual partition ordermax residual partition orderrice parameter search dist
0falsefalsetukey(0.5)00falsefalsefalse030
1truetruetukey(0.5)00falsefalsefalse030
2truefalsetukey(0.5)00falsefalsefalse030
3falsefalsetukey(0.5)60falsefalsefalse040
4truetruetukey(0.5)80falsefalsefalse040
5truefalsetukey(0.5)80falsefalsefalse050
6truefalsetukey(0.5)80falsefalsefalse060
7truefalsetukey(0.5)80falsefalsetrue060
8truefalsetukey(0.5)120falsefalsetrue060

Default Value:
5
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_blocksize (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the blocksize to use while encoding.

The number of samples to use per frame. Use 0 to let the encoder estimate a blocksize; this is usually best.

Default Value:
0
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_do_mid_side_stereo (  FLAC__StreamEncoder *  encoder,
FLAC__bool  value
) 
 

Set to true to enable mid-side encoding on stereo input. The number of channels must be 2 for this to have any effect. Set to false to use only independent channel coding.

Default Value:
false
Parameters:
encoder An encoder instance to set.
value Flag value (see above).
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_loose_mid_side_stereo (  FLAC__StreamEncoder *  encoder,
FLAC__bool  value
) 
 

Set to true to enable adaptive switching between mid-side and left-right encoding on stereo input. Set to false to use exhaustive searching. Setting this to true requires FLAC__stream_encoder_set_do_mid_side_stereo() to also be set to true in order to have any effect.

Default Value:
false
Parameters:
encoder An encoder instance to set.
value Flag value (see above).
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_apodization (  FLAC__StreamEncoder *  encoder,
const char *  specification
) 
 

Sets the apodization function(s) the encoder will use when windowing audio data for LPC analysis.

The specification is a plain ASCII string which specifies exactly which functions to use. There may be more than one (up to 32), separated by ';' characters. Some functions take one or more comma-separated arguments in parentheses.

The available functions are bartlett, bartlett_hann, blackman, blackman_harris_4term_92db, connes, flattop, gauss(STDDEV), hamming, hann, kaiser_bessel, nuttall, rectangle, triangle, tukey(P), welch.

For gauss(STDDEV), STDDEV specifies the standard deviation (0<STDDEV<=0.5).

For tukey(P), P specifies the fraction of the window that is tapered (0<=P<=1). P=0 corresponds to rectangle and P=1 corresponds to hann.

Example specifications are "blackman" or "hann;triangle;tukey(0.5);tukey(0.25);tukey(0.125)"

Any function that is specified erroneously is silently dropped. Up to 32 functions are kept, the rest are dropped. If the specification is empty the encoder defaults to "tukey(0.5)".

When more than one function is specified, then for every subframe the encoder will try each of them separately and choose the window that results in the smallest compressed subframe.

Note that each function specified causes the encoder to occupy a floating point array in which to store the window.

Default Value:
"tukey(0.5)"
Parameters:
encoder An encoder instance to set.
specification See above.
Assertions: 
 encoder != NULL 

 specification != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_max_lpc_order (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the maximum LPC order, or 0 to use only the fixed predictors.

Default Value:
0
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_qlp_coeff_precision (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the precision, in bits, of the quantized linear predictor coefficients, or 0 to let the encoder select it based on the blocksize.

Note:
In the current implementation, qlp_coeff_precision + bits_per_sample must be less than 32.
Default Value:
0
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_do_qlp_coeff_prec_search (  FLAC__StreamEncoder *  encoder,
FLAC__bool  value
) 
 

Set to false to use only the specified quantized linear predictor coefficient precision, or true to search neighboring precision values and use the best one.

Default Value:
false
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_do_escape_coding (  FLAC__StreamEncoder *  encoder,
FLAC__bool  value
) 
 

Deprecated. Setting this value has no effect.

Default Value:
false
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_do_exhaustive_model_search (  FLAC__StreamEncoder *  encoder,
FLAC__bool  value
) 
 

Set to false to let the encoder estimate the best model order based on the residual signal energy, or true to force the encoder to evaluate all order models and select the best.

Default Value:
false
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_min_residual_partition_order (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the minimum partition order to search when coding the residual. This is used in tandem with FLAC__stream_encoder_set_max_residual_partition_order().

The partition order determines the context size in the residual. The context size will be approximately blocksize / (2 ^ order).

Set both min and max values to 0 to force a single context, whose Rice parameter is based on the residual signal variance. Otherwise, set a min and max order, and the encoder will search all orders, using the mean of each context for its Rice parameter, and use the best.

Default Value:
0
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_max_residual_partition_order (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Set the maximum partition order to search when coding the residual. This is used in tandem with FLAC__stream_encoder_set_min_residual_partition_order().

The partition order determines the context size in the residual. The context size will be approximately blocksize / (2 ^ order).

Set both min and max values to 0 to force a single context, whose Rice parameter is based on the residual signal variance. Otherwise, set a min and max order, and the encoder will search all orders, using the mean of each context for its Rice parameter, and use the best.

Default Value:
0
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_rice_parameter_search_dist (  FLAC__StreamEncoder *  encoder,
unsigned  value
) 
 

Deprecated. Setting this value has no effect.

Default Value:
0
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_total_samples_estimate (  FLAC__StreamEncoder *  encoder,
FLAC__uint64  value
) 
 

Set an estimate of the total samples that will be encoded. This is merely an estimate and may be set to 0 if unknown. This value will be written to the STREAMINFO block before encoding, and can remove the need for the caller to rewrite the value later if the value is known before encoding.

Default Value:
0
Parameters:
encoder An encoder instance to set.
value See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true.

FLAC__bool FLAC__stream_encoder_set_metadata (  FLAC__StreamEncoder *  encoder,
FLAC__StreamMetadata **  metadata,
unsigned  num_blocks
) 
 

Set the metadata blocks to be emitted to the stream before encoding. A value of NULL, 0 implies no metadata; otherwise, supply an array of pointers to metadata blocks. The array is non-const since the encoder may need to change the is_last flag inside them, and in some cases update seek point offsets. Otherwise, the encoder will not modify or free the blocks. It is up to the caller to free the metadata blocks after encoding finishes.

Note:
The encoder stores only copies of the pointers in the metadata array; the metadata blocks themselves must survive at least until after FLAC__stream_encoder_finish() returns. Do not free the blocks until then.

The STREAMINFO block is always written and no STREAMINFO block may occur in the supplied array.

By default the encoder does not create a SEEKTABLE. If one is supplied in the metadata array, but the client has specified that it does not support seeking, then the SEEKTABLE will be written verbatim. However by itself this is not very useful as the client will not know the stream offsets for the seekpoints ahead of time. In order to get a proper seektable the client must support seeking. See next note.

SEEKTABLE blocks are handled specially. Since you will not know the values for the seek point stream offsets, you should pass in a SEEKTABLE 'template', that is, a SEEKTABLE object with the required sample numbers (or placeholder points), with 0 for the frame_samples and stream_offset fields for each point. If the client has specified that it supports seeking by providing a seek callback to FLAC__stream_encoder_init_stream() or both seek AND read callback to FLAC__stream_encoder_init_ogg_stream() (or by using FLAC__stream_encoder_init*_file() or FLAC__stream_encoder_init*_FILE()), then while it is encoding the encoder will fill the stream offsets in for you and when encoding is finished, it will seek back and write the real values into the SEEKTABLE block in the stream. There are helper routines for manipulating seektable template blocks; see metadata.h: FLAC__metadata_object_seektable_template_*(). If the client does not support seeking, the SEEKTABLE will have inaccurate offsets which will slow down or remove the ability to seek in the FLAC stream.

The encoder instance will modify the first SEEKTABLE block as it transforms the template to a valid seektable while encoding, but it is still up to the caller to free all metadata blocks after encoding.

A VORBIS_COMMENT block may be supplied. The vendor string in it will be ignored. libFLAC will use it's own vendor string. libFLAC will not modify the passed-in VORBIS_COMMENT's vendor string, it will simply write it's own into the stream. If no VORBIS_COMMENT block is present in the metadata array, libFLAC will write an empty one, containing only the vendor string.

The Ogg FLAC mapping requires that the VORBIS_COMMENT block be the second metadata block of the stream. The encoder already supplies the STREAMINFO block automatically. If metadata does not contain a VORBIS_COMMENT block, the encoder will supply that too. Otherwise, if metadata does contain a VORBIS_COMMENT block and it is not the first, the init function will reorder metadata by moving the VORBIS_COMMENT block to the front; the relative ordering of the other blocks will remain as they were.

The Ogg FLAC mapping limits the number of metadata blocks per stream to 65535. If num_blocks exceeds this the function will return false.

Default Value:
NULL, 0
Parameters:
encoder An encoder instance to set.
metadata See above.
num_blocks See above.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if the encoder is already initialized, else true. false if the encoder is already initialized, or if num_blocks > 65535 if encoding to Ogg FLAC, else true.

FLAC__StreamEncoderState FLAC__stream_encoder_get_state (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the current encoder state.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__StreamEncoderState The current encoder state.

FLAC__StreamDecoderState FLAC__stream_encoder_get_verify_decoder_state (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the state of the verify stream decoder. Useful when the stream encoder state is FLAC__STREAM_ENCODER_VERIFY_DECODER_ERROR.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__StreamDecoderState The verify stream decoder state.

const char* FLAC__stream_encoder_get_resolved_state_string (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the current encoder state as a C string. This version automatically resolves FLAC__STREAM_ENCODER_VERIFY_DECODER_ERROR by getting the verify decoder's state.

Parameters:
encoder A encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
const char * The encoder state as a C string. Do not modify the contents.

void FLAC__stream_encoder_get_verify_decoder_error_stats (  const FLAC__StreamEncoder *  encoder,
FLAC__uint64 *  absolute_sample,
unsigned *  frame_number,
unsigned *  channel,
unsigned *  sample,
FLAC__int32 *  expected,
FLAC__int32 *  got
) 
 

Get relevant values about the nature of a verify decoder error. Useful when the stream encoder state is FLAC__STREAM_ENCODER_VERIFY_DECODER_ERROR. The arguments should be addresses in which the stats will be returned, or NULL if value is not desired.

Parameters:
encoder An encoder instance to query.
absolute_sample The absolute sample number of the mismatch.
frame_number The number of the frame in which the mismatch occurred.
channel The channel in which the mismatch occurred.
sample The number of the sample (relative to the frame) in which the mismatch occurred.
expected The expected value for the sample in question.
got The actual value returned by the decoder.
Assertions: 
 encoder != NULL

FLAC__bool FLAC__stream_encoder_get_verify (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the "verify" flag.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool See FLAC__stream_encoder_set_verify().

FLAC__bool FLAC__stream_encoder_get_streamable_subset (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the <A HREF="../format.html#subset>Subset flag.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool See FLAC__stream_encoder_set_streamable_subset().

unsigned FLAC__stream_encoder_get_channels (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the number of input channels being processed.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_channels().

unsigned FLAC__stream_encoder_get_bits_per_sample (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the input sample resolution setting.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_bits_per_sample().

unsigned FLAC__stream_encoder_get_sample_rate (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the input sample rate setting.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_sample_rate().

unsigned FLAC__stream_encoder_get_blocksize (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the blocksize setting.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_blocksize().

FLAC__bool FLAC__stream_encoder_get_do_mid_side_stereo (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the "mid/side stereo coding" flag.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool See FLAC__stream_encoder_get_do_mid_side_stereo().

FLAC__bool FLAC__stream_encoder_get_loose_mid_side_stereo (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the "adaptive mid/side switching" flag.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool See FLAC__stream_encoder_set_loose_mid_side_stereo().

unsigned FLAC__stream_encoder_get_max_lpc_order (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the maximum LPC order setting.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_max_lpc_order().

unsigned FLAC__stream_encoder_get_qlp_coeff_precision (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the quantized linear predictor coefficient precision setting.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_qlp_coeff_precision().

FLAC__bool FLAC__stream_encoder_get_do_qlp_coeff_prec_search (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the qlp coefficient precision search flag.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool See FLAC__stream_encoder_set_do_qlp_coeff_prec_search().

FLAC__bool FLAC__stream_encoder_get_do_escape_coding (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the "escape coding" flag.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool See FLAC__stream_encoder_set_do_escape_coding().

FLAC__bool FLAC__stream_encoder_get_do_exhaustive_model_search (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the exhaustive model search flag.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool See FLAC__stream_encoder_set_do_exhaustive_model_search().

unsigned FLAC__stream_encoder_get_min_residual_partition_order (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the minimum residual partition order setting.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_min_residual_partition_order().

unsigned FLAC__stream_encoder_get_max_residual_partition_order (  const FLAC__StreamEncoder *  encoder  ) 
 

Get maximum residual partition order setting.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_max_residual_partition_order().

unsigned FLAC__stream_encoder_get_rice_parameter_search_dist (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the Rice parameter search distance setting.

Parameters:
encoder An encoder instance to query.
Assertions: 
 encoder != NULL
Return values:
unsigned See FLAC__stream_encoder_set_rice_parameter_search_dist().

FLAC__uint64 FLAC__stream_encoder_get_total_samples_estimate (  const FLAC__StreamEncoder *  encoder  ) 
 

Get the previously set estimate of the total samples to be encoded. The encoder merely mimics back the value given to FLAC__stream_encoder_set_total_samples_estimate() since it has no other way of knowing how many samples the client will encode.

Parameters:
encoder An encoder instance to set.
Assertions: 
 encoder != NULL
Return values:
FLAC__uint64 See FLAC__stream_encoder_get_total_samples_estimate().

FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_stream (  FLAC__StreamEncoder *  encoder,
FLAC__StreamEncoderWriteCallback  write_callback,
FLAC__StreamEncoderSeekCallback  seek_callback,
FLAC__StreamEncoderTellCallback  tell_callback,
FLAC__StreamEncoderMetadataCallback  metadata_callback,
void *  client_data
) 
 

Initialize the encoder instance to encode native FLAC streams.

This flavor of initialization sets up the encoder to encode to a native FLAC stream. I/O is performed via callbacks to the client. For encoding to a plain file via filename or open FILE*, FLAC__stream_encoder_init_file() and FLAC__stream_encoder_init_FILE() provide a simpler interface.

This function should be called after FLAC__stream_encoder_new() and FLAC__stream_encoder_set_*() but before FLAC__stream_encoder_process() or FLAC__stream_encoder_process_interleaved(). initialization succeeded.

The call to FLAC__stream_encoder_init_stream() currently will also immediately call the write callback several times, once with the fLaC signature, and once for each encoded metadata block.

Parameters:
encoder An uninitialized encoder instance.
write_callback See FLAC__StreamEncoderWriteCallback. This pointer must not be NULL.
seek_callback See FLAC__StreamEncoderSeekCallback. This pointer may be NULL if seeking is not supported. The encoder uses seeking to go back and write some some stream statistics to the STREAMINFO block; this is recommended but not necessary to create a valid FLAC stream. If seek_callback is not NULL then a tell_callback must also be supplied. Alternatively, a dummy seek callback that just returns FLAC__STREAM_ENCODER_SEEK_STATUS_UNSUPPORTED may also be supplied, all though this is slightly less efficient for the encoder.
tell_callback See FLAC__StreamEncoderTellCallback. This pointer may be NULL if seeking is not supported. If seek_callback is NULL then this argument will be ignored. If seek_callback is not NULL then a tell_callback must also be supplied. Alternatively, a dummy tell callback that just returns FLAC__STREAM_ENCODER_TELL_STATUS_UNSUPPORTED may also be supplied, all though this is slightly less efficient for the encoder.
metadata_callback See FLAC__StreamEncoderMetadataCallback. This pointer may be NULL if the callback is not desired. If the client provides a seek callback, this function is not necessary as the encoder will automatically seek back and update the STREAMINFO block. It may also be NULL if the client does not support seeking, since it will have no way of going back to update the STREAMINFO. However the client can still supply a callback if it would like to know the details from the STREAMINFO.
client_data This value will be supplied to callbacks in their client_data argument.
Assertions: 
 encoder != NULL
Return values:
FLAC__StreamEncoderInitStatus FLAC__STREAM_ENCODER_INIT_STATUS_OK if initialization was successful; see FLAC__StreamEncoderInitStatus for the meanings of other return values.

FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_ogg_stream (  FLAC__StreamEncoder *  encoder,
FLAC__StreamEncoderReadCallback  read_callback,
FLAC__StreamEncoderWriteCallback  write_callback,
FLAC__StreamEncoderSeekCallback  seek_callback,
FLAC__StreamEncoderTellCallback  tell_callback,
FLAC__StreamEncoderMetadataCallback  metadata_callback,
void *  client_data
) 
 

Initialize the encoder instance to encode Ogg FLAC streams.

This flavor of initialization sets up the encoder to encode to a FLAC stream in an Ogg container. I/O is performed via callbacks to the client. For encoding to a plain file via filename or open FILE*, FLAC__stream_encoder_init_ogg_file() and FLAC__stream_encoder_init_ogg_FILE() provide a simpler interface.

This function should be called after FLAC__stream_encoder_new() and FLAC__stream_encoder_set_*() but before FLAC__stream_encoder_process() or FLAC__stream_encoder_process_interleaved(). initialization succeeded.

The call to FLAC__stream_encoder_init_ogg_stream() currently will also immediately call the write callback several times to write the metadata packets.

Parameters:
encoder An uninitialized encoder instance.
read_callback See FLAC__StreamEncoderReadCallback. This pointer must not be NULL if seek_callback is non-NULL since they are both needed to be able to write data back to the Ogg FLAC stream in the post-encode phase.
write_callback See FLAC__StreamEncoderWriteCallback. This pointer must not be NULL.
seek_callback See FLAC__StreamEncoderSeekCallback. This pointer may be NULL if seeking is not supported. The encoder uses seeking to go back and write some some stream statistics to the STREAMINFO block; this is recommended but not necessary to create a valid FLAC stream. If seek_callback is not NULL then a tell_callback must also be supplied. Alternatively, a dummy seek callback that just returns FLAC__STREAM_ENCODER_SEEK_STATUS_UNSUPPORTED may also be supplied, all though this is slightly less efficient for the encoder.
tell_callback See FLAC__StreamEncoderTellCallback. This pointer may be NULL if seeking is not supported. If seek_callback is NULL then this argument will be ignored. If seek_callback is not NULL then a tell_callback must also be supplied. Alternatively, a dummy tell callback that just returns FLAC__STREAM_ENCODER_TELL_STATUS_UNSUPPORTED may also be supplied, all though this is slightly less efficient for the encoder.
metadata_callback See FLAC__StreamEncoderMetadataCallback. This pointer may be NULL if the callback is not desired. If the client provides a seek callback, this function is not necessary as the encoder will automatically seek back and update the STREAMINFO block. It may also be NULL if the client does not support seeking, since it will have no way of going back to update the STREAMINFO. However the client can still supply a callback if it would like to know the details from the STREAMINFO.
client_data This value will be supplied to callbacks in their client_data argument.
Assertions: 
 encoder != NULL
Return values:
FLAC__StreamEncoderInitStatus FLAC__STREAM_ENCODER_INIT_STATUS_OK if initialization was successful; see FLAC__StreamEncoderInitStatus for the meanings of other return values.

FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_FILE (  FLAC__StreamEncoder *  encoder,
FILE *  file,
FLAC__StreamEncoderProgressCallback  progress_callback,
void *  client_data
) 
 

Initialize the encoder instance to encode native FLAC files.

This flavor of initialization sets up the encoder to encode to a plain native FLAC file. For non-stdio streams, you must use FLAC__stream_encoder_init_stream() and provide callbacks for the I/O.

This function should be called after FLAC__stream_encoder_new() and FLAC__stream_encoder_set_*() but before FLAC__stream_encoder_process() or FLAC__stream_encoder_process_interleaved(). initialization succeeded.

Parameters:
encoder An uninitialized encoder instance.
file An open file. The file should have been opened with mode "w+b" and rewound. The file becomes owned by the encoder and should not be manipulated by the client while encoding. Unless file is stdout, it will be closed when FLAC__stream_encoder_finish() is called. Note however that a proper SEEKTABLE cannot be created when encoding to stdout since it is not seekable.
progress_callback See FLAC__StreamEncoderProgressCallback. This pointer may be NULL if the callback is not desired.
client_data This value will be supplied to callbacks in their client_data argument.
Assertions: 
 encoder != NULL 

 file != NULL
Return values:
FLAC__StreamEncoderInitStatus FLAC__STREAM_ENCODER_INIT_STATUS_OK if initialization was successful; see FLAC__StreamEncoderInitStatus for the meanings of other return values.

FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_ogg_FILE (  FLAC__StreamEncoder *  encoder,
FILE *  file,
FLAC__StreamEncoderProgressCallback  progress_callback,
void *  client_data
) 
 

Initialize the encoder instance to encode Ogg FLAC files.

This flavor of initialization sets up the encoder to encode to a plain Ogg FLAC file. For non-stdio streams, you must use FLAC__stream_encoder_init_ogg_stream() and provide callbacks for the I/O.

This function should be called after FLAC__stream_encoder_new() and FLAC__stream_encoder_set_*() but before FLAC__stream_encoder_process() or FLAC__stream_encoder_process_interleaved(). initialization succeeded.

Parameters:
encoder An uninitialized encoder instance.
file An open file. The file should have been opened with mode "w+b" and rewound. The file becomes owned by the encoder and should not be manipulated by the client while encoding. Unless file is stdout, it will be closed when FLAC__stream_encoder_finish() is called. Note however that a proper SEEKTABLE cannot be created when encoding to stdout since it is not seekable.
progress_callback See FLAC__StreamEncoderProgressCallback. This pointer may be NULL if the callback is not desired.
client_data This value will be supplied to callbacks in their client_data argument.
Assertions: 
 encoder != NULL 

 file != NULL
Return values:
FLAC__StreamEncoderInitStatus FLAC__STREAM_ENCODER_INIT_STATUS_OK if initialization was successful; see FLAC__StreamEncoderInitStatus for the meanings of other return values.

FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_file (  FLAC__StreamEncoder *  encoder,
const char *  filename,
FLAC__StreamEncoderProgressCallback  progress_callback,
void *  client_data
) 
 

Initialize the encoder instance to encode native FLAC files.

This flavor of initialization sets up the encoder to encode to a plain FLAC file. If POSIX fopen() semantics are not sufficient (for example, with Unicode filenames on Windows), you must use FLAC__stream_encoder_init_FILE(), or FLAC__stream_encoder_init_stream() and provide callbacks for the I/O.

This function should be called after FLAC__stream_encoder_new() and FLAC__stream_encoder_set_*() but before FLAC__stream_encoder_process() or FLAC__stream_encoder_process_interleaved(). initialization succeeded.

Parameters:
encoder An uninitialized encoder instance.
filename The name of the file to encode to. The file will be opened with fopen(). Use NULL to encode to stdout. Note however that a proper SEEKTABLE cannot be created when encoding to stdout since it is not seekable.
progress_callback See FLAC__StreamEncoderProgressCallback. This pointer may be NULL if the callback is not desired.
client_data This value will be supplied to callbacks in their client_data argument.
Assertions: 
 encoder != NULL
Return values:
FLAC__StreamEncoderInitStatus FLAC__STREAM_ENCODER_INIT_STATUS_OK if initialization was successful; see FLAC__StreamEncoderInitStatus for the meanings of other return values.

FLAC__StreamEncoderInitStatus FLAC__stream_encoder_init_ogg_file (  FLAC__StreamEncoder *  encoder,
const char *  filename,
FLAC__StreamEncoderProgressCallback  progress_callback,
void *  client_data
) 
 

Initialize the encoder instance to encode Ogg FLAC files.

This flavor of initialization sets up the encoder to encode to a plain Ogg FLAC file. If POSIX fopen() semantics are not sufficient (for example, with Unicode filenames on Windows), you must use FLAC__stream_encoder_init_ogg_FILE(), or FLAC__stream_encoder_init_ogg_stream() and provide callbacks for the I/O.

This function should be called after FLAC__stream_encoder_new() and FLAC__stream_encoder_set_*() but before FLAC__stream_encoder_process() or FLAC__stream_encoder_process_interleaved(). initialization succeeded.

Parameters:
encoder An uninitialized encoder instance.
filename The name of the file to encode to. The file will be opened with fopen(). Use NULL to encode to stdout. Note however that a proper SEEKTABLE cannot be created when encoding to stdout since it is not seekable.
progress_callback See FLAC__StreamEncoderProgressCallback. This pointer may be NULL if the callback is not desired.
client_data This value will be supplied to callbacks in their client_data argument.
Assertions: 
 encoder != NULL
Return values:
FLAC__StreamEncoderInitStatus FLAC__STREAM_ENCODER_INIT_STATUS_OK if initialization was successful; see FLAC__StreamEncoderInitStatus for the meanings of other return values.

FLAC__bool FLAC__stream_encoder_finish (  FLAC__StreamEncoder *  encoder  ) 
 

Finish the encoding process. Flushes the encoding buffer, releases resources, resets the encoder settings to their defaults, and returns the encoder state to FLAC__STREAM_ENCODER_UNINITIALIZED. Note that this can generate one or more write callbacks before returning, and will generate a metadata callback.

Note that in the course of processing the last frame, errors can occur, so the caller should be sure to check the return value to ensure the file was encoded properly.

In the event of a prematurely-terminated encode, it is not strictly necessary to call this immediately before FLAC__stream_encoder_delete() but it is good practice to match every FLAC__stream_encoder_init_*() with a FLAC__stream_encoder_finish().

Parameters:
encoder An uninitialized encoder instance.
Assertions: 
 encoder != NULL
Return values:
FLAC__bool false if an error occurred processing the last frame; or if verify mode is set (see FLAC__stream_encoder_set_verify()), there was a verify mismatch; else true. If false, caller should check the state with FLAC__stream_encoder_get_state() for more information about the error.

FLAC__bool FLAC__stream_encoder_process (  FLAC__StreamEncoder *  encoder,
const FLAC__int32 *const   buffer[],
unsigned  samples
) 
 

Submit data for encoding. This version allows you to supply the input data via an array of pointers, each pointer pointing to an array of samples samples representing one channel. The samples need not be block-aligned, but each channel should have the same number of samples. Each sample should be a signed integer, right-justified to the resolution set by FLAC__stream_encoder_set_bits_per_sample(). For example, if the resolution is 16 bits per sample, the samples should all be in the range [-32768,32767].

For applications where channel order is important, channels must follow the order as described in the frame header.

Parameters:
encoder An initialized encoder instance in the OK state.
buffer An array of pointers to each channel's signal.
samples The number of samples in one channel.
Assertions: 
 encoder != NULL 

 FLAC__stream_encoder_get_state(encoder) == FLAC__STREAM_ENCODER_OK
Return values:
FLAC__bool true if successful, else false; in this case, check the encoder state with FLAC__stream_encoder_get_state() to see what went wrong.

FLAC__bool FLAC__stream_encoder_process_interleaved (  FLAC__StreamEncoder *  encoder,
const FLAC__int32  buffer[],
unsigned  samples
) 
 

Submit data for encoding. This version allows you to supply the input data where the channels are interleaved into a single array (i.e. channel0_sample0, channel1_sample0, ... , channelN_sample0, channel0_sample1, ...). The samples need not be block-aligned but they must be sample-aligned, i.e. the first value should be channel0_sample0 and the last value channelN_sampleM. Each sample should be a signed integer, right-justified to the resolution set by FLAC__stream_encoder_set_bits_per_sample(). For example, if the resolution is 16 bits per sample, the samples should all be in the range [-32768,32767].

For applications where channel order is important, channels must follow the order as described in the frame header.

Parameters:
encoder An initialized encoder instance in the OK state.
buffer An array of channel-interleaved data (see above).
samples The number of samples in one channel, the same as for FLAC__stream_encoder_process(). For example, if encoding two channels, 1000 samples corresponds to a buffer of 2000 values.
Assertions: 
 encoder != NULL 

 FLAC__stream_encoder_get_state(encoder) == FLAC__STREAM_ENCODER_OK
Return values:
FLAC__bool true if successful, else false; in this case, check the encoder state with FLAC__stream_encoder_get_state() to see what went wrong.

Variable Documentation

const char* const FLAC__StreamEncoderStateString[]
 

Maps a FLAC__StreamEncoderState to a C string.

Using a FLAC__StreamEncoderState as the index to this array will give the string equivalent. The contents should not be modified.

const char* const FLAC__StreamEncoderInitStatusString[]
 

Maps a FLAC__StreamEncoderInitStatus to a C string.

Using a FLAC__StreamEncoderInitStatus as the index to this array will give the string equivalent. The contents should not be modified.

const char* const FLAC__StreamEncoderReadStatusString[]
 

Maps a FLAC__StreamEncoderReadStatus to a C string.

Using a FLAC__StreamEncoderReadStatus as the index to this array will give the string equivalent. The contents should not be modified.

const char* const FLAC__StreamEncoderWriteStatusString[]
 

Maps a FLAC__StreamEncoderWriteStatus to a C string.

Using a FLAC__StreamEncoderWriteStatus as the index to this array will give the string equivalent. The contents should not be modified.

const char* const FLAC__StreamEncoderSeekStatusString[]
 

Maps a FLAC__StreamEncoderSeekStatus to a C string.

Using a FLAC__StreamEncoderSeekStatus as the index to this array will give the string equivalent. The contents should not be modified.

const char* const FLAC__StreamEncoderTellStatusString[]
 

Maps a FLAC__StreamEncoderTellStatus to a C string.

Using a FLAC__StreamEncoderTellStatus as the index to this array will give the string equivalent. The contents should not be modified.

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