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1
/*
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 * IEC 61937 muxer
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 * Copyright (c) 2009 Bartlomiej Wolowiec
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 * Copyright (c) 2010 Anssi Hannula
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 * Copyright (c) 2010 Carl Eugen Hoyos
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
10
 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
23

    
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/**
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 * @file
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 * IEC-61937 encapsulation of various formats, used by S/PDIF
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 * @author Bartlomiej Wolowiec
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 * @author Anssi Hannula
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 * @author Carl Eugen Hoyos
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 */
31

    
32
/*
33
 * Terminology used in specification:
34
 * data-burst - IEC61937 frame, contains header and encapsuled frame
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 * burst-preambule - IEC61937 frame header, contains 16-bits words named Pa, Pb, Pc and Pd
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 * burst-payload - encapsuled frame
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 * Pa, Pb - syncword - 0xF872, 0x4E1F
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 * Pc - burst-info, contains data-type (bits 0-6), error flag (bit 7), data-type-dependent info (bits 8-12)
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 *      and bitstream number (bits 13-15)
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 * data-type - determines type of encapsuled frames
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 * Pd - length code (number of bits or bytes of encapsuled frame - according to data_type)
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 *
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 * IEC 61937 frames at normal usage start every specific count of bytes,
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 *      dependent from data-type (spaces between packets are filled by zeros)
45
 */
46

    
47
#include "avformat.h"
48
#include "spdif.h"
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#include "libavcodec/ac3.h"
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#include "libavcodec/dca.h"
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#include "libavcodec/dcadata.h"
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#include "libavcodec/aacadtsdec.h"
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#include "libavutil/opt.h"
54

    
55
typedef struct IEC61937Context {
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    const AVClass *av_class;
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    enum IEC61937DataType data_type;///< burst info - reference to type of payload of the data-burst
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    int length_code;                ///< length code in bits or bytes, depending on data type
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    int pkt_offset;                 ///< data burst repetition period in bytes
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    uint8_t *buffer;                ///< allocated buffer, used for swap bytes
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    int buffer_size;                ///< size of allocated buffer
62

    
63
    uint8_t *out_buf;               ///< pointer to the outgoing data before byte-swapping
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    int out_bytes;                  ///< amount of outgoing bytes
65

    
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    int use_preamble;               ///< preamble enabled (disabled for exactly pre-padded DTS)
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    int extra_bswap;                ///< extra bswap for payload (for LE DTS => standard BE DTS)
68

    
69
    uint8_t *hd_buf;                ///< allocated buffer to concatenate hd audio frames
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    int hd_buf_size;                ///< size of the hd audio buffer
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    int hd_buf_count;               ///< number of frames in the hd audio buffer
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    int hd_buf_filled;              ///< amount of bytes in the hd audio buffer
73

    
74
    int dtshd_skip;                 ///< counter used for skipping DTS-HD frames
75

    
76
    /* AVOptions: */
77
    int dtshd_rate;
78
    int dtshd_fallback;
79

    
80
    /// function, which generates codec dependent header information.
81
    /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
82
    int (*header_info) (AVFormatContext *s, AVPacket *pkt);
83
} IEC61937Context;
84

    
85
static const AVOption options[] = {
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{ "dtshd_rate", "mux complete DTS frames in HD mode at the specified IEC958 rate (in Hz, default 0=disabled)", offsetof(IEC61937Context, dtshd_rate), FF_OPT_TYPE_INT, 0, 0, 768000, AV_OPT_FLAG_ENCODING_PARAM },
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{ "dtshd_fallback_time", "min secs to strip HD for after an overflow (-1: till the end, default 60)", offsetof(IEC61937Context, dtshd_fallback), FF_OPT_TYPE_INT, 60, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
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{ NULL },
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};
90

    
91
static const AVClass class = { "spdif", av_default_item_name, options, LIBAVUTIL_VERSION_INT };
92

    
93
static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)
94
{
95
    IEC61937Context *ctx = s->priv_data;
96
    int bitstream_mode = pkt->data[5] & 0x7;
97

    
98
    ctx->data_type  = IEC61937_AC3 | (bitstream_mode << 8);
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    ctx->pkt_offset = AC3_FRAME_SIZE << 2;
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    return 0;
101
}
102

    
103
static int spdif_header_eac3(AVFormatContext *s, AVPacket *pkt)
104
{
105
    IEC61937Context *ctx = s->priv_data;
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    static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
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    int repeat = 1;
108

    
109
    if ((pkt->data[4] & 0xc0) != 0xc0) /* fscod */
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        repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */
111

    
112
    ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);
113
    if (!ctx->hd_buf)
114
        return AVERROR(ENOMEM);
115

    
116
    memcpy(&ctx->hd_buf[ctx->hd_buf_filled], pkt->data, pkt->size);
117

    
118
    ctx->hd_buf_filled += pkt->size;
119
    if (++ctx->hd_buf_count < repeat){
120
        ctx->pkt_offset = 0;
121
        return 0;
122
    }
123
    ctx->data_type   = IEC61937_EAC3;
124
    ctx->pkt_offset  = 24576;
125
    ctx->out_buf     = ctx->hd_buf;
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    ctx->out_bytes   = ctx->hd_buf_filled;
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    ctx->length_code = ctx->hd_buf_filled;
128

    
129
    ctx->hd_buf_count  = 0;
130
    ctx->hd_buf_filled = 0;
131
    return 0;
132
}
133

    
134
/*
135
 * DTS type IV (DTS-HD) can be transmitted with various frame repetition
136
 * periods; longer repetition periods allow for longer packets and therefore
137
 * higher bitrate. Longer repetition periods mean that the constant bitrate of
138
 * the outputted IEC 61937 stream is higher.
139
 * The repetition period is measured in IEC 60958 frames (4 bytes).
140
 */
141
enum {
142
    DTS4_REP_PER_512   = 0x0,
143
    DTS4_REP_PER_1024  = 0x1,
144
    DTS4_REP_PER_2048  = 0x2,
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    DTS4_REP_PER_4096  = 0x3,
146
    DTS4_REP_PER_8192  = 0x4,
147
    DTS4_REP_PER_16384 = 0x5,
148
};
149

    
150
static int spdif_dts4_subtype(int period)
151
{
152
    switch (period) {
153
    case 512:   return DTS4_REP_PER_512;
154
    case 1024:  return DTS4_REP_PER_1024;
155
    case 2048:  return DTS4_REP_PER_2048;
156
    case 4096:  return DTS4_REP_PER_4096;
157
    case 8192:  return DTS4_REP_PER_8192;
158
    case 16384: return DTS4_REP_PER_16384;
159
    }
160
    return -1;
161
}
162

    
163
static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,
164
                             int sample_rate, int blocks)
165
{
166
    IEC61937Context *ctx = s->priv_data;
167
    static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
168
    int pkt_size = pkt->size;
169
    int period;
170
    int subtype;
171

    
172
    if (!core_size) {
173
        av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");
174
        return AVERROR(EINVAL);
175
    }
176

    
177
    if (!sample_rate) {
178
        av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");
179
        return AVERROR_INVALIDDATA;
180
    }
181

    
182
    period = ctx->dtshd_rate * (blocks << 5) / sample_rate;
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    subtype = spdif_dts4_subtype(period);
184

    
185
    if (subtype < 0) {
186
        av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "
187
               "impossible repetition period of %d for the current DTS stream"
188
               " (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,
189
               blocks << 5, sample_rate);
190
        return AVERROR(EINVAL);
191
    }
192

    
193
    /* set pkt_offset and DTS IV subtype according to the requested output
194
     * rate */
195
    ctx->pkt_offset = period * 4;
196
    ctx->data_type = IEC61937_DTSHD | subtype << 8;
197

    
198
    /* If the bitrate is too high for transmitting at the selected
199
     * repetition period setting, strip DTS-HD until a good amount
200
     * of consecutive non-overflowing HD frames have been observed.
201
     * This generally only happens if the caller is cramming a Master
202
     * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
203
    if (sizeof(dtshd_start_code) + 2 + pkt_size
204
            > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {
205
        if (!ctx->dtshd_skip)
206
            av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "
207
                                      "temporarily sending core only\n");
208
        if (ctx->dtshd_fallback > 0)
209
            ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
210
        else
211
            /* skip permanently (-1) or just once (0) */
212
            ctx->dtshd_skip = 1;
213
    }
214
    if (ctx->dtshd_skip && core_size) {
215
        pkt_size = core_size;
216
        if (ctx->dtshd_fallback >= 0)
217
            --ctx->dtshd_skip;
218
    }
219

    
220
    ctx->out_bytes   = sizeof(dtshd_start_code) + 2 + pkt_size;
221
    ctx->length_code = ctx->out_bytes;
222

    
223
    ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size,
224
                                  ctx->out_bytes);
225
    if (!ctx->hd_buf)
226
        return AVERROR(ENOMEM);
227

    
228
    ctx->out_buf = ctx->hd_buf;
229

    
230
    memcpy(ctx->hd_buf, dtshd_start_code, sizeof(dtshd_start_code));
231
    AV_WB16(ctx->hd_buf + sizeof(dtshd_start_code), pkt_size);
232
    memcpy(ctx->hd_buf + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);
233

    
234
    return 0;
235
}
236

    
237
static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
238
{
239
    IEC61937Context *ctx = s->priv_data;
240
    uint32_t syncword_dts = AV_RB32(pkt->data);
241
    int blocks;
242
    int sample_rate = 0;
243
    int core_size = 0;
244

    
245
    if (pkt->size < 9)
246
        return AVERROR_INVALIDDATA;
247

    
248
    switch (syncword_dts) {
249
    case DCA_MARKER_RAW_BE:
250
        blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
251
        core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;
252
        sample_rate = dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];
253
        break;
254
    case DCA_MARKER_RAW_LE:
255
        blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
256
        ctx->extra_bswap = 1;
257
        break;
258
    case DCA_MARKER_14B_BE:
259
        blocks =
260
            (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
261
        break;
262
    case DCA_MARKER_14B_LE:
263
        blocks =
264
            (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
265
        ctx->extra_bswap = 1;
266
        break;
267
    case DCA_HD_MARKER:
268
        /* We only handle HD frames that are paired with core. However,
269
           sometimes DTS-HD streams with core have a stray HD frame without
270
           core in the beginning of the stream. */
271
        av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");
272
        return AVERROR_INVALIDDATA;
273
    default:
274
        av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);
275
        return AVERROR_INVALIDDATA;
276
    }
277
    blocks++;
278

    
279
    if (ctx->dtshd_rate)
280
        /* DTS type IV output requested */
281
        return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);
282

    
283
    switch (blocks) {
284
    case  512 >> 5: ctx->data_type = IEC61937_DTS1; break;
285
    case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;
286
    case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;
287
    default:
288
        av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
289
               blocks << 5);
290
        return AVERROR(ENOSYS);
291
    }
292

    
293
    /* discard extraneous data by default */
294
    if (core_size && core_size < pkt->size) {
295
        ctx->out_bytes = core_size;
296
        ctx->length_code = core_size << 3;
297
    }
298

    
299
    ctx->pkt_offset = blocks << 7;
300

    
301
    if (ctx->out_bytes == ctx->pkt_offset) {
302
        /* The DTS stream fits exactly into the output stream, so skip the
303
         * preamble as it would not fit in there. This is the case for dts
304
         * discs and dts-in-wav. */
305
        ctx->use_preamble = 0;
306
    } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {
307
        av_log_ask_for_sample(s, "Unrecognized large DTS frame.");
308
        /* This will fail with a "bitrate too high" in the caller */
309
    }
310

    
311
    return 0;
312
}
313

    
314
static const enum IEC61937DataType mpeg_data_type[2][3] = {
315
    //     LAYER1                      LAYER2                  LAYER3
316
    { IEC61937_MPEG2_LAYER1_LSF, IEC61937_MPEG2_LAYER2_LSF, IEC61937_MPEG2_LAYER3_LSF },//MPEG2 LSF
317
    { IEC61937_MPEG1_LAYER1,     IEC61937_MPEG1_LAYER23,    IEC61937_MPEG1_LAYER23 },   //MPEG1
318
};
319

    
320
static int spdif_header_mpeg(AVFormatContext *s, AVPacket *pkt)
321
{
322
    IEC61937Context *ctx = s->priv_data;
323
    int version =      (pkt->data[1] >> 3) & 3;
324
    int layer   = 3 - ((pkt->data[1] >> 1) & 3);
325
    int extension = pkt->data[2] & 1;
326

    
327
    if (layer == 3 || version == 1) {
328
        av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
329
        return AVERROR_INVALIDDATA;
330
    }
331
    av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
332
    if (version == 2 && extension) {
333
        ctx->data_type  = IEC61937_MPEG2_EXT;
334
        ctx->pkt_offset = 4608;
335
    } else {
336
        ctx->data_type  = mpeg_data_type [version & 1][layer];
337
        ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];
338
    }
339
    // TODO Data type dependant info (normal/karaoke, dynamic range control)
340
    return 0;
341
}
342

    
343
static int spdif_header_aac(AVFormatContext *s, AVPacket *pkt)
344
{
345
    IEC61937Context *ctx = s->priv_data;
346
    AACADTSHeaderInfo hdr;
347
    GetBitContext gbc;
348
    int ret;
349

    
350
    init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);
351
    ret = ff_aac_parse_header(&gbc, &hdr);
352
    if (ret < 0) {
353
        av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
354
        return AVERROR_INVALIDDATA;
355
    }
356

    
357
    ctx->pkt_offset = hdr.samples << 2;
358
    switch (hdr.num_aac_frames) {
359
    case 1:
360
        ctx->data_type = IEC61937_MPEG2_AAC;
361
        break;
362
    case 2:
363
        ctx->data_type = IEC61937_MPEG2_AAC_LSF_2048;
364
        break;
365
    case 4:
366
        ctx->data_type = IEC61937_MPEG2_AAC_LSF_4096;
367
        break;
368
    default:
369
        av_log(s, AV_LOG_ERROR, "%i samples in AAC frame not supported\n",
370
               hdr.samples);
371
        return AVERROR(EINVAL);
372
    }
373
    //TODO Data type dependent info (LC profile/SBR)
374
    return 0;
375
}
376

    
377

    
378
/*
379
 * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
380
 * they can be encapsulated in IEC 61937.
381
 * Here we encapsulate 24 TrueHD frames in a single MAT frame, padding them
382
 * to achieve constant rate.
383
 * The actual format of a MAT frame is unknown, but the below seems to work.
384
 * However, it seems it is not actually necessary for the 24 TrueHD frames to
385
 * be in an exact alignment with the MAT frame.
386
 */
387
#define MAT_FRAME_SIZE          61424
388
#define TRUEHD_FRAME_OFFSET     2560
389
#define MAT_MIDDLE_CODE_OFFSET  -4
390

    
391
static int spdif_header_truehd(AVFormatContext *s, AVPacket *pkt)
392
{
393
    IEC61937Context *ctx = s->priv_data;
394
    int mat_code_length = 0;
395
    const char mat_end_code[16] = { 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11 };
396

    
397
    if (!ctx->hd_buf_count) {
398
        const char mat_start_code[20] = { 0x07, 0x9E, 0x00, 0x03, 0x84, 0x01, 0x01, 0x01, 0x80, 0x00, 0x56, 0xA5, 0x3B, 0xF4, 0x81, 0x83, 0x49, 0x80, 0x77, 0xE0 };
399
        mat_code_length = sizeof(mat_start_code) + BURST_HEADER_SIZE;
400
        memcpy(ctx->hd_buf, mat_start_code, sizeof(mat_start_code));
401

    
402
    } else if (ctx->hd_buf_count == 12) {
403
        const char mat_middle_code[12] = { 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0 };
404
        mat_code_length = sizeof(mat_middle_code) + MAT_MIDDLE_CODE_OFFSET;
405
        memcpy(&ctx->hd_buf[12 * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + MAT_MIDDLE_CODE_OFFSET],
406
               mat_middle_code, sizeof(mat_middle_code));
407
    }
408

    
409
    if (pkt->size > TRUEHD_FRAME_OFFSET - mat_code_length) {
410
        /* if such frames exist, we'd need some more complex logic to
411
         * distribute the TrueHD frames in the MAT frame */
412
        av_log(s, AV_LOG_ERROR, "TrueHD frame too big, %d bytes\n", pkt->size);
413
        av_log_ask_for_sample(s, NULL);
414
        return AVERROR_INVALIDDATA;
415
    }
416

    
417
    memcpy(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length],
418
           pkt->data, pkt->size);
419
    memset(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length + pkt->size],
420
           0, TRUEHD_FRAME_OFFSET - pkt->size - mat_code_length);
421

    
422
    if (++ctx->hd_buf_count < 24){
423
        ctx->pkt_offset = 0;
424
        return 0;
425
    }
426
    memcpy(&ctx->hd_buf[MAT_FRAME_SIZE - sizeof(mat_end_code)], mat_end_code, sizeof(mat_end_code));
427
    ctx->hd_buf_count = 0;
428

    
429
    ctx->data_type   = IEC61937_TRUEHD;
430
    ctx->pkt_offset  = 61440;
431
    ctx->out_buf     = ctx->hd_buf;
432
    ctx->out_bytes   = MAT_FRAME_SIZE;
433
    ctx->length_code = MAT_FRAME_SIZE;
434
    return 0;
435
}
436

    
437
static int spdif_write_header(AVFormatContext *s)
438
{
439
    IEC61937Context *ctx = s->priv_data;
440

    
441
    switch (s->streams[0]->codec->codec_id) {
442
    case CODEC_ID_AC3:
443
        ctx->header_info = spdif_header_ac3;
444
        break;
445
    case CODEC_ID_EAC3:
446
        ctx->header_info = spdif_header_eac3;
447
        break;
448
    case CODEC_ID_MP1:
449
    case CODEC_ID_MP2:
450
    case CODEC_ID_MP3:
451
        ctx->header_info = spdif_header_mpeg;
452
        break;
453
    case CODEC_ID_DTS:
454
        ctx->header_info = spdif_header_dts;
455
        break;
456
    case CODEC_ID_AAC:
457
        ctx->header_info = spdif_header_aac;
458
        break;
459
    case CODEC_ID_TRUEHD:
460
        ctx->header_info = spdif_header_truehd;
461
        ctx->hd_buf = av_malloc(MAT_FRAME_SIZE);
462
        if (!ctx->hd_buf)
463
            return AVERROR(ENOMEM);
464
        break;
465
    default:
466
        av_log(s, AV_LOG_ERROR, "codec not supported\n");
467
        return AVERROR_PATCHWELCOME;
468
    }
469
    return 0;
470
}
471

    
472
static int spdif_write_trailer(AVFormatContext *s)
473
{
474
    IEC61937Context *ctx = s->priv_data;
475
    av_freep(&ctx->buffer);
476
    av_freep(&ctx->hd_buf);
477
    return 0;
478
}
479

    
480
static int spdif_write_packet(struct AVFormatContext *s, AVPacket *pkt)
481
{
482
    IEC61937Context *ctx = s->priv_data;
483
    int ret, padding;
484

    
485
    ctx->out_buf = pkt->data;
486
    ctx->out_bytes = pkt->size;
487
    ctx->length_code = FFALIGN(pkt->size, 2) << 3;
488
    ctx->use_preamble = 1;
489
    ctx->extra_bswap = 0;
490

    
491
    ret = ctx->header_info(s, pkt);
492
    if (ret < 0)
493
        return ret;
494
    if (!ctx->pkt_offset)
495
        return 0;
496

    
497
    padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;
498
    if (padding < 0) {
499
        av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
500
        return AVERROR(EINVAL);
501
    }
502

    
503
    if (ctx->use_preamble) {
504
        put_le16(s->pb, SYNCWORD1);       //Pa
505
        put_le16(s->pb, SYNCWORD2);       //Pb
506
        put_le16(s->pb, ctx->data_type);  //Pc
507
        put_le16(s->pb, ctx->length_code);//Pd
508
    }
509

    
510
    if (HAVE_BIGENDIAN ^ ctx->extra_bswap) {
511
    put_buffer(s->pb, ctx->out_buf, ctx->out_bytes & ~1);
512
    } else {
513
    av_fast_malloc(&ctx->buffer, &ctx->buffer_size, ctx->out_bytes + FF_INPUT_BUFFER_PADDING_SIZE);
514
    if (!ctx->buffer)
515
        return AVERROR(ENOMEM);
516
    ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);
517
    put_buffer(s->pb, ctx->buffer, ctx->out_bytes & ~1);
518
    }
519

    
520
    if (ctx->out_bytes & 1)
521
        put_be16(s->pb, ctx->out_buf[ctx->out_bytes - 1]);
522

    
523
    put_nbyte(s->pb, 0, padding);
524

    
525
    av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
526
           ctx->data_type, ctx->out_bytes, ctx->pkt_offset);
527

    
528
    put_flush_packet(s->pb);
529
    return 0;
530
}
531

    
532
AVOutputFormat ff_spdif_muxer = {
533
    "spdif",
534
    NULL_IF_CONFIG_SMALL("IEC 61937 (used on S/PDIF - IEC958)"),
535
    NULL,
536
    "spdif",
537
    sizeof(IEC61937Context),
538
    CODEC_ID_AC3,
539
    CODEC_ID_NONE,
540
    spdif_write_header,
541
    spdif_write_packet,
542
    spdif_write_trailer,
543
    .priv_class = &class,
544
};