1/*
2 * IEC958 muxer
3 * Copyright (c) 2009 Bartlomiej Wolowiec
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * IEC-61937 encapsulation of various formats, used by S/PDIF
25 * @author Bartlomiej Wolowiec
26 */
27
28/*
29 * Terminology used in specification:
30 * data-burst - IEC958 frame, contains header and encapsuled frame
31 * burst-preambule - IEC958 frame header, contains 16-bits words named Pa, Pb, Pc and Pd
32 * burst-payload - encapsuled frame
33 * Pa, Pb - syncword - 0xF872, 0x4E1F
34 * Pc - burst-info, contains data-type (bits 0-6), error flag (bit 7), data-type-dependent info (bits 8-12)
35 *      and bitstream number (bits 13-15)
36 * data-type - determines type of encapsuled frames
37 * Pd - length code (number of bits or bytes of encapsuled frame - according to data_type)
38 *
39 * IEC958 frames at normal usage start every specific count of bytes,
40 *      dependent from data-type (spaces between packets are filled by zeros)
41 */
42
43#include "avformat.h"
44#include "libavcodec/ac3.h"
45#include "libavcodec/dca.h"
46#include "libavcodec/aac_parser.h"
47
48#define SYNCWORD1 0xF872
49#define SYNCWORD2 0x4E1F
50#define BURST_HEADER_SIZE 0x8
51
52enum IEC958DataType {
53    IEC958_AC3                = 0x01,          ///< AC-3 data
54    IEC958_MPEG1_LAYER1       = 0x04,          ///< MPEG-1 layer 1
55    IEC958_MPEG1_LAYER23      = 0x05,          ///< MPEG-1 layer 2 or 3 data or MPEG-2 without extension
56    IEC958_MPEG2_EXT          = 0x06,          ///< MPEG-2 data with extension
57    IEC958_MPEG2_AAC          = 0x07,          ///< MPEG-2 AAC ADTS
58    IEC958_MPEG2_LAYER1_LSF   = 0x08,          ///< MPEG-2, layer-1 low sampling frequency
59    IEC958_MPEG2_LAYER2_LSF   = 0x09,          ///< MPEG-2, layer-2 low sampling frequency
60    IEC958_MPEG2_LAYER3_LSF   = 0x0A,          ///< MPEG-2, layer-3 low sampling frequency
61    IEC958_DTS1               = 0x0B,          ///< DTS type I   (512 samples)
62    IEC958_DTS2               = 0x0C,          ///< DTS type II  (1024 samples)
63    IEC958_DTS3               = 0x0D,          ///< DTS type III (2048 samples)
64    IEC958_MPEG2_AAC_LSF_2048 = 0x13,          ///< MPEG-2 AAC ADTS half-rate low sampling frequency
65    IEC958_MPEG2_AAC_LSF_4096 = 0x13 | 0x20,   ///< MPEG-2 AAC ADTS quarter-rate low sampling frequency
66};
67
68typedef struct IEC958Context {
69    enum IEC958DataType data_type;  ///< burst info - reference to type of payload of the data-burst
70    int pkt_size;                   ///< length code in bits
71    int pkt_offset;                 ///< data burst repetition period in bytes
72    uint8_t *buffer;                ///< allocated buffer, used for swap bytes
73    int buffer_size;                ///< size of allocated buffer
74
75    /// function, which generates codec dependent header information.
76    /// Sets data_type and data_offset
77    int (*header_info) (AVFormatContext *s, AVPacket *pkt);
78} IEC958Context;
79
80//TODO move to DSP
81static void bswap_buf16(uint16_t *dst, const uint16_t *src, int w)
82{
83    int i;
84
85    for (i = 0; i + 8 <= w; i += 8) {
86        dst[i + 0] = bswap_16(src[i + 0]);
87        dst[i + 1] = bswap_16(src[i + 1]);
88        dst[i + 2] = bswap_16(src[i + 2]);
89        dst[i + 3] = bswap_16(src[i + 3]);
90        dst[i + 4] = bswap_16(src[i + 4]);
91        dst[i + 5] = bswap_16(src[i + 5]);
92        dst[i + 6] = bswap_16(src[i + 6]);
93        dst[i + 7] = bswap_16(src[i + 7]);
94    }
95    for (; i < w; i++)
96        dst[i + 0] = bswap_16(src[i + 0]);
97}
98
99static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)
100{
101    IEC958Context *ctx = s->priv_data;
102    int bitstream_mode = pkt->data[6] & 0x7;
103
104    ctx->data_type  = IEC958_AC3 | (bitstream_mode << 8);
105    ctx->pkt_offset = AC3_FRAME_SIZE << 2;
106    return 0;
107}
108
109static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
110{
111    IEC958Context *ctx = s->priv_data;
112    uint32_t syncword_dts = AV_RB32(pkt->data);
113    int blocks;
114
115    switch (syncword_dts) {
116    case DCA_MARKER_RAW_BE:
117        blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
118        break;
119    case DCA_MARKER_RAW_LE:
120        blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
121        break;
122    case DCA_MARKER_14B_BE:
123        blocks =
124            (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
125        break;
126    case DCA_MARKER_14B_LE:
127        blocks =
128            (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
129        break;
130    default:
131        av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);
132        return -1;
133    }
134    blocks++;
135    switch (blocks) {
136    case  512 >> 5: ctx->data_type = IEC958_DTS1; break;
137    case 1024 >> 5: ctx->data_type = IEC958_DTS2; break;
138    case 2048 >> 5: ctx->data_type = IEC958_DTS3; break;
139    default:
140        av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
141               blocks << 5);
142        return -1;
143    }
144    ctx->pkt_offset = blocks << 7;
145
146    return 0;
147}
148
149static const enum IEC958DataType mpeg_data_type[2][3] = {
150    //     LAYER1                      LAYER2                  LAYER3
151    { IEC958_MPEG2_LAYER1_LSF, IEC958_MPEG2_LAYER2_LSF, IEC958_MPEG2_LAYER3_LSF },  //MPEG2 LSF
152    { IEC958_MPEG1_LAYER1,     IEC958_MPEG1_LAYER23,    IEC958_MPEG1_LAYER23 },     //MPEG1
153};
154
155static const uint16_t mpeg_pkt_offset[2][3] = {
156    //LAYER1  LAYER2  LAYER3
157    { 3072,    9216,   4608 }, // MPEG2 LSF
158    { 1536,    4608,   4608 }, // MPEG1
159};
160
161static int spdif_header_mpeg(AVFormatContext *s, AVPacket *pkt)
162{
163    IEC958Context *ctx = s->priv_data;
164    int version =      (pkt->data[1] >> 3) & 3;
165    int layer   = 3 - ((pkt->data[1] >> 1) & 3);
166    int extension = pkt->data[2] & 1;
167
168    if (layer == 3 || version == 1) {
169        av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
170        return -1;
171    }
172    av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
173    if (version == 2 && extension) {
174        ctx->data_type  = IEC958_MPEG2_EXT;
175        ctx->pkt_offset = 4608;
176    } else {
177        ctx->data_type  = mpeg_data_type [version & 1][layer];
178        ctx->pkt_offset = mpeg_pkt_offset[version & 1][layer];
179    }
180    // TODO Data type dependant info (normal/karaoke, dynamic range control)
181    return 0;
182}
183
184static int spdif_header_aac(AVFormatContext *s, AVPacket *pkt)
185{
186    IEC958Context *ctx = s->priv_data;
187    AACADTSHeaderInfo hdr;
188    GetBitContext gbc;
189    int ret;
190
191    init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);
192    ret = ff_aac_parse_header(&gbc, &hdr);
193    if (ret < 0) {
194        av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
195        return -1;
196    }
197
198    ctx->pkt_offset = hdr.samples << 2;
199    switch (hdr.num_aac_frames) {
200    case 1:
201        ctx->data_type = IEC958_MPEG2_AAC;
202        break;
203    case 2:
204        ctx->data_type = IEC958_MPEG2_AAC_LSF_2048;
205        break;
206    case 4:
207        ctx->data_type = IEC958_MPEG2_AAC_LSF_4096;
208        break;
209    default:
210        av_log(s, AV_LOG_ERROR, "%i samples in AAC frame not supported\n",
211               hdr.samples);
212        return -1;
213    }
214    //TODO Data type dependent info (LC profile/SBR)
215    return 0;
216}
217
218static int spdif_write_header(AVFormatContext *s)
219{
220    IEC958Context *ctx = s->priv_data;
221
222    switch (s->streams[0]->codec->codec_id) {
223    case CODEC_ID_AC3:
224        ctx->header_info = spdif_header_ac3;
225        break;
226    case CODEC_ID_MP1:
227    case CODEC_ID_MP2:
228    case CODEC_ID_MP3:
229        ctx->header_info = spdif_header_mpeg;
230        break;
231    case CODEC_ID_DTS:
232        ctx->header_info = spdif_header_dts;
233        break;
234    case CODEC_ID_AAC:
235        ctx->header_info = spdif_header_aac;
236        break;
237    default:
238        av_log(s, AV_LOG_ERROR, "codec not supported\n");
239        return -1;
240    }
241    return 0;
242}
243
244static int spdif_write_trailer(AVFormatContext *s)
245{
246    IEC958Context *ctx = s->priv_data;
247    av_freep(&ctx->buffer);
248    return 0;
249}
250
251static int spdif_write_packet(struct AVFormatContext *s, AVPacket *pkt)
252{
253    IEC958Context *ctx = s->priv_data;
254    int ret, padding;
255
256    ctx->pkt_size = FFALIGN(pkt->size, 2) << 3;
257    ret = ctx->header_info(s, pkt);
258    if (ret < 0)
259        return -1;
260
261    padding = (ctx->pkt_offset - BURST_HEADER_SIZE - pkt->size) >> 1;
262    if (padding < 0) {
263        av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
264        return -1;
265    }
266
267    put_le16(s->pb, SYNCWORD1);      //Pa
268    put_le16(s->pb, SYNCWORD2);      //Pb
269    put_le16(s->pb, ctx->data_type); //Pc
270    put_le16(s->pb, ctx->pkt_size);  //Pd
271
272#if HAVE_BIGENDIAN
273    put_buffer(s->pb, pkt->data, pkt->size & ~1);
274#else
275    av_fast_malloc(&ctx->buffer, &ctx->buffer_size, pkt->size + FF_INPUT_BUFFER_PADDING_SIZE);
276    if (!ctx->buffer)
277        return AVERROR(ENOMEM);
278    bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)pkt->data, pkt->size >> 1);
279    put_buffer(s->pb, ctx->buffer, pkt->size & ~1);
280#endif
281
282    if (pkt->size & 1)
283        put_be16(s->pb, pkt->data[pkt->size - 1]);
284
285    for (; padding > 0; padding--)
286        put_be16(s->pb, 0);
287
288    av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
289           ctx->data_type, pkt->size, ctx->pkt_offset);
290
291    put_flush_packet(s->pb);
292    return 0;
293}
294
295AVOutputFormat spdif_muxer = {
296    "spdif",
297    NULL_IF_CONFIG_SMALL("IEC958 - S/PDIF (IEC-61937)"),
298    NULL,
299    "spdif",
300    sizeof(IEC958Context),
301    CODEC_ID_AC3,
302    CODEC_ID_NONE,
303    spdif_write_header,
304    spdif_write_packet,
305    spdif_write_trailer,
306};
307