1/* 2 * SMPTE 302M encoder 3 * Copyright (c) 2010 Google, Inc. 4 * Copyright (c) 2013 Darryl Wallace <wallacdj@gmail.com> 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "avcodec.h" 24#include "internal.h" 25#include "mathops.h" 26#include "put_bits.h" 27 28#define AES3_HEADER_LEN 4 29 30typedef struct S302MEncContext { 31 uint8_t framing_index; /* Set for even channels on multiple of 192 samples */ 32} S302MEncContext; 33 34static av_cold int s302m_encode_init(AVCodecContext *avctx) 35{ 36 S302MEncContext *s = avctx->priv_data; 37 38 if (avctx->channels & 1 || avctx->channels > 8) { 39 av_log(avctx, AV_LOG_ERROR, 40 "Encoding %d channel(s) is not allowed. Only 2, 4, 6 and 8 channels are supported.\n", 41 avctx->channels); 42 return AVERROR(EINVAL); 43 } 44 45 switch (avctx->sample_fmt) { 46 case AV_SAMPLE_FMT_S16: 47 avctx->bits_per_raw_sample = 16; 48 break; 49 case AV_SAMPLE_FMT_S32: 50 if (avctx->bits_per_raw_sample > 20) { 51 if (avctx->bits_per_raw_sample > 24) 52 av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n"); 53 avctx->bits_per_raw_sample = 24; 54 } else if (!avctx->bits_per_raw_sample) { 55 avctx->bits_per_raw_sample = 24; 56 } else if (avctx->bits_per_raw_sample <= 20) { 57 avctx->bits_per_raw_sample = 20; 58 } 59 } 60 61 avctx->frame_size = 0; 62 avctx->bit_rate = 48000 * avctx->channels * 63 (avctx->bits_per_raw_sample + 4); 64 s->framing_index = 0; 65 66 return 0; 67} 68 69static int s302m_encode2_frame(AVCodecContext *avctx, AVPacket *avpkt, 70 const AVFrame *frame, int *got_packet_ptr) 71{ 72 S302MEncContext *s = avctx->priv_data; 73 const int buf_size = AES3_HEADER_LEN + 74 (frame->nb_samples * 75 avctx->channels * 76 (avctx->bits_per_raw_sample + 4)) / 8; 77 int ret, c, channels; 78 uint8_t *o; 79 PutBitContext pb; 80 81 if ((ret = ff_alloc_packet2(avctx, avpkt, buf_size)) < 0) 82 return ret; 83 84 o = avpkt->data; 85 init_put_bits(&pb, o, buf_size * 8); 86 put_bits(&pb, 16, buf_size - AES3_HEADER_LEN); 87 put_bits(&pb, 2, (avctx->channels - 2) >> 1); // number of channels 88 put_bits(&pb, 8, 0); // channel ID 89 put_bits(&pb, 2, (avctx->bits_per_raw_sample - 16) / 4); // bits per samples (0 = 16bit, 1 = 20bit, 2 = 24bit) 90 put_bits(&pb, 4, 0); // alignments 91 flush_put_bits(&pb); 92 o += AES3_HEADER_LEN; 93 94 if (avctx->bits_per_raw_sample == 24) { 95 const uint32_t *samples = (uint32_t *)frame->data[0]; 96 97 for (c = 0; c < frame->nb_samples; c++) { 98 uint8_t vucf = s->framing_index == 0 ? 0x10: 0; 99 100 for (channels = 0; channels < avctx->channels; channels += 2) { 101 o[0] = ff_reverse[(samples[0] & 0x0000FF00) >> 8]; 102 o[1] = ff_reverse[(samples[0] & 0x00FF0000) >> 16]; 103 o[2] = ff_reverse[(samples[0] & 0xFF000000) >> 24]; 104 o[3] = ff_reverse[(samples[1] & 0x00000F00) >> 4] | vucf; 105 o[4] = ff_reverse[(samples[1] & 0x000FF000) >> 12]; 106 o[5] = ff_reverse[(samples[1] & 0x0FF00000) >> 20]; 107 o[6] = ff_reverse[(samples[1] & 0xF0000000) >> 28]; 108 o += 7; 109 samples += 2; 110 } 111 112 s->framing_index++; 113 if (s->framing_index >= 192) 114 s->framing_index = 0; 115 } 116 } else if (avctx->bits_per_raw_sample == 20) { 117 const uint32_t *samples = (uint32_t *)frame->data[0]; 118 119 for (c = 0; c < frame->nb_samples; c++) { 120 uint8_t vucf = s->framing_index == 0 ? 0x80: 0; 121 122 for (channels = 0; channels < avctx->channels; channels += 2) { 123 o[0] = ff_reverse[ (samples[0] & 0x000FF000) >> 12]; 124 o[1] = ff_reverse[ (samples[0] & 0x0FF00000) >> 20]; 125 o[2] = ff_reverse[((samples[0] & 0xF0000000) >> 28) | vucf]; 126 o[3] = ff_reverse[ (samples[1] & 0x000FF000) >> 12]; 127 o[4] = ff_reverse[ (samples[1] & 0x0FF00000) >> 20]; 128 o[5] = ff_reverse[ (samples[1] & 0xF0000000) >> 28]; 129 o += 6; 130 samples += 2; 131 } 132 133 s->framing_index++; 134 if (s->framing_index >= 192) 135 s->framing_index = 0; 136 } 137 } else if (avctx->bits_per_raw_sample == 16) { 138 const uint16_t *samples = (uint16_t *)frame->data[0]; 139 140 for (c = 0; c < frame->nb_samples; c++) { 141 uint8_t vucf = s->framing_index == 0 ? 0x10 : 0; 142 143 for (channels = 0; channels < avctx->channels; channels += 2) { 144 o[0] = ff_reverse[ samples[0] & 0xFF]; 145 o[1] = ff_reverse[(samples[0] & 0xFF00) >> 8]; 146 o[2] = ff_reverse[(samples[1] & 0x0F) << 4] | vucf; 147 o[3] = ff_reverse[(samples[1] & 0x0FF0) >> 4]; 148 o[4] = ff_reverse[(samples[1] & 0xF000) >> 12]; 149 o += 5; 150 samples += 2; 151 152 } 153 154 s->framing_index++; 155 if (s->framing_index >= 192) 156 s->framing_index = 0; 157 } 158 } 159 160 *got_packet_ptr = 1; 161 162 return 0; 163} 164 165AVCodec ff_s302m_encoder = { 166 .name = "s302m", 167 .long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"), 168 .type = AVMEDIA_TYPE_AUDIO, 169 .id = AV_CODEC_ID_S302M, 170 .priv_data_size = sizeof(S302MEncContext), 171 .init = s302m_encode_init, 172 .encode2 = s302m_encode2_frame, 173 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32, 174 AV_SAMPLE_FMT_S16, 175 AV_SAMPLE_FMT_NONE }, 176 .capabilities = CODEC_CAP_VARIABLE_FRAME_SIZE | CODEC_CAP_EXPERIMENTAL, 177 .supported_samplerates = (const int[]) { 48000, 0 }, 178}; 179