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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:
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 * 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)
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 */
46

    
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#include "avformat.h"
48
#include "avio_internal.h"
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#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"
55

    
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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
63

    
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    uint8_t *out_buf;               ///< pointer to the outgoing data before byte-swapping
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    int out_bytes;                  ///< amount of outgoing bytes
66

    
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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)
69

    
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    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
74

    
75
    int dtshd_skip;                 ///< counter used for skipping DTS-HD frames
76

    
77
    /* AVOptions: */
78
    int dtshd_rate;
79
    int dtshd_fallback;
80
#define SPDIF_FLAG_BIGENDIAN    0x01
81
    int spdif_flags;
82

    
83
    /// function, which generates codec dependent header information.
84
    /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
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    int (*header_info) (AVFormatContext *s, AVPacket *pkt);
86
} IEC61937Context;
87

    
88
static const AVOption options[] = {
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{ "spdif_flags", "IEC 61937 encapsulation flags", offsetof(IEC61937Context, spdif_flags), FF_OPT_TYPE_FLAGS, 0, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },
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{ "be", "output in big-endian format (for use as s16be)", 0, FF_OPT_TYPE_CONST, SPDIF_FLAG_BIGENDIAN, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },
91
{ "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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};
95

    
96
static const AVClass class = { "spdif", av_default_item_name, options, LIBAVUTIL_VERSION_INT };
97

    
98
static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)
99
{
100
    IEC61937Context *ctx = s->priv_data;
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    int bitstream_mode = pkt->data[5] & 0x7;
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103
    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;
106
}
107

    
108
static int spdif_header_eac3(AVFormatContext *s, AVPacket *pkt)
109
{
110
    IEC61937Context *ctx = s->priv_data;
111
    static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
112
    int repeat = 1;
113

    
114
    if ((pkt->data[4] & 0xc0) != 0xc0) /* fscod */
115
        repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */
116

    
117
    ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);
118
    if (!ctx->hd_buf)
119
        return AVERROR(ENOMEM);
120

    
121
    memcpy(&ctx->hd_buf[ctx->hd_buf_filled], pkt->data, pkt->size);
122

    
123
    ctx->hd_buf_filled += pkt->size;
124
    if (++ctx->hd_buf_count < repeat){
125
        ctx->pkt_offset = 0;
126
        return 0;
127
    }
128
    ctx->data_type   = IEC61937_EAC3;
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    ctx->pkt_offset  = 24576;
130
    ctx->out_buf     = ctx->hd_buf;
131
    ctx->out_bytes   = ctx->hd_buf_filled;
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    ctx->length_code = ctx->hd_buf_filled;
133

    
134
    ctx->hd_buf_count  = 0;
135
    ctx->hd_buf_filled = 0;
136
    return 0;
137
}
138

    
139
/*
140
 * DTS type IV (DTS-HD) can be transmitted with various frame repetition
141
 * periods; longer repetition periods allow for longer packets and therefore
142
 * higher bitrate. Longer repetition periods mean that the constant bitrate of
143
 * the outputted IEC 61937 stream is higher.
144
 * The repetition period is measured in IEC 60958 frames (4 bytes).
145
 */
146
static int spdif_dts4_subtype(int period)
147
{
148
    switch (period) {
149
    case 512:   return 0x0;
150
    case 1024:  return 0x1;
151
    case 2048:  return 0x2;
152
    case 4096:  return 0x3;
153
    case 8192:  return 0x4;
154
    case 16384: return 0x5;
155
    }
156
    return -1;
157
}
158

    
159
static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,
160
                             int sample_rate, int blocks)
161
{
162
    IEC61937Context *ctx = s->priv_data;
163
    static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
164
    int pkt_size = pkt->size;
165
    int period;
166
    int subtype;
167

    
168
    if (!core_size) {
169
        av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");
170
        return AVERROR(EINVAL);
171
    }
172

    
173
    if (!sample_rate) {
174
        av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");
175
        return AVERROR_INVALIDDATA;
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    }
177

    
178
    period = ctx->dtshd_rate * (blocks << 5) / sample_rate;
179
    subtype = spdif_dts4_subtype(period);
180

    
181
    if (subtype < 0) {
182
        av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "
183
               "impossible repetition period of %d for the current DTS stream"
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               " (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,
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               blocks << 5, sample_rate);
186
        return AVERROR(EINVAL);
187
    }
188

    
189
    /* set pkt_offset and DTS IV subtype according to the requested output
190
     * rate */
191
    ctx->pkt_offset = period * 4;
192
    ctx->data_type = IEC61937_DTSHD | subtype << 8;
193

    
194
    /* If the bitrate is too high for transmitting at the selected
195
     * repetition period setting, strip DTS-HD until a good amount
196
     * of consecutive non-overflowing HD frames have been observed.
197
     * This generally only happens if the caller is cramming a Master
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     * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
199
    if (sizeof(dtshd_start_code) + 2 + pkt_size
200
            > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {
201
        if (!ctx->dtshd_skip)
202
            av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "
203
                                      "temporarily sending core only\n");
204
        if (ctx->dtshd_fallback > 0)
205
            ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
206
        else
207
            /* skip permanently (dtshd_fallback == -1) or just once
208
             * (dtshd_fallback == 0) */
209
            ctx->dtshd_skip = 1;
210
    }
211
    if (ctx->dtshd_skip && core_size) {
212
        pkt_size = core_size;
213
        if (ctx->dtshd_fallback >= 0)
214
            --ctx->dtshd_skip;
215
    }
216

    
217
    ctx->out_bytes   = sizeof(dtshd_start_code) + 2 + pkt_size;
218
    ctx->length_code = ctx->out_bytes;
219

    
220
    av_fast_malloc(&ctx->hd_buf, &ctx->hd_buf_size, ctx->out_bytes);
221
    if (!ctx->hd_buf)
222
        return AVERROR(ENOMEM);
223

    
224
    ctx->out_buf = ctx->hd_buf;
225

    
226
    memcpy(ctx->hd_buf, dtshd_start_code, sizeof(dtshd_start_code));
227
    AV_WB16(ctx->hd_buf + sizeof(dtshd_start_code), pkt_size);
228
    memcpy(ctx->hd_buf + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);
229

    
230
    return 0;
231
}
232

    
233
static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
234
{
235
    IEC61937Context *ctx = s->priv_data;
236
    uint32_t syncword_dts = AV_RB32(pkt->data);
237
    int blocks;
238
    int sample_rate = 0;
239
    int core_size = 0;
240

    
241
    if (pkt->size < 9)
242
        return AVERROR_INVALIDDATA;
243

    
244
    switch (syncword_dts) {
245
    case DCA_MARKER_RAW_BE:
246
        blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
247
        core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;
248
        sample_rate = dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];
249
        break;
250
    case DCA_MARKER_RAW_LE:
251
        blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
252
        ctx->extra_bswap = 1;
253
        break;
254
    case DCA_MARKER_14B_BE:
255
        blocks =
256
            (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
257
        break;
258
    case DCA_MARKER_14B_LE:
259
        blocks =
260
            (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
261
        ctx->extra_bswap = 1;
262
        break;
263
    case DCA_HD_MARKER:
264
        /* We only handle HD frames that are paired with core. However,
265
           sometimes DTS-HD streams with core have a stray HD frame without
266
           core in the beginning of the stream. */
267
        av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");
268
        return AVERROR_INVALIDDATA;
269
    default:
270
        av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);
271
        return AVERROR_INVALIDDATA;
272
    }
273
    blocks++;
274

    
275
    if (ctx->dtshd_rate)
276
        /* DTS type IV output requested */
277
        return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);
278

    
279
    switch (blocks) {
280
    case  512 >> 5: ctx->data_type = IEC61937_DTS1; break;
281
    case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;
282
    case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;
283
    default:
284
        av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
285
               blocks << 5);
286
        return AVERROR(ENOSYS);
287
    }
288

    
289
    /* discard extraneous data by default */
290
    if (core_size && core_size < pkt->size) {
291
        ctx->out_bytes = core_size;
292
        ctx->length_code = core_size << 3;
293
    }
294

    
295
    ctx->pkt_offset = blocks << 7;
296

    
297
    if (ctx->out_bytes == ctx->pkt_offset) {
298
        /* The DTS stream fits exactly into the output stream, so skip the
299
         * preamble as it would not fit in there. This is the case for dts
300
         * discs and dts-in-wav. */
301
        ctx->use_preamble = 0;
302
    } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {
303
        av_log_ask_for_sample(s, "Unrecognized large DTS frame.");
304
        /* This will fail with a "bitrate too high" in the caller */
305
    }
306

    
307
    return 0;
308
}
309

    
310
static const enum IEC61937DataType mpeg_data_type[2][3] = {
311
    //     LAYER1                      LAYER2                  LAYER3
312
    { IEC61937_MPEG2_LAYER1_LSF, IEC61937_MPEG2_LAYER2_LSF, IEC61937_MPEG2_LAYER3_LSF },//MPEG2 LSF
313
    { IEC61937_MPEG1_LAYER1,     IEC61937_MPEG1_LAYER23,    IEC61937_MPEG1_LAYER23 },   //MPEG1
314
};
315

    
316
static int spdif_header_mpeg(AVFormatContext *s, AVPacket *pkt)
317
{
318
    IEC61937Context *ctx = s->priv_data;
319
    int version =      (pkt->data[1] >> 3) & 3;
320
    int layer   = 3 - ((pkt->data[1] >> 1) & 3);
321
    int extension = pkt->data[2] & 1;
322

    
323
    if (layer == 3 || version == 1) {
324
        av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
325
        return AVERROR_INVALIDDATA;
326
    }
327
    av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
328
    if (version == 2 && extension) {
329
        ctx->data_type  = IEC61937_MPEG2_EXT;
330
        ctx->pkt_offset = 4608;
331
    } else {
332
        ctx->data_type  = mpeg_data_type [version & 1][layer];
333
        ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];
334
    }
335
    // TODO Data type dependant info (normal/karaoke, dynamic range control)
336
    return 0;
337
}
338

    
339
static int spdif_header_aac(AVFormatContext *s, AVPacket *pkt)
340
{
341
    IEC61937Context *ctx = s->priv_data;
342
    AACADTSHeaderInfo hdr;
343
    GetBitContext gbc;
344
    int ret;
345

    
346
    init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);
347
    ret = ff_aac_parse_header(&gbc, &hdr);
348
    if (ret < 0) {
349
        av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
350
        return AVERROR_INVALIDDATA;
351
    }
352

    
353
    ctx->pkt_offset = hdr.samples << 2;
354
    switch (hdr.num_aac_frames) {
355
    case 1:
356
        ctx->data_type = IEC61937_MPEG2_AAC;
357
        break;
358
    case 2:
359
        ctx->data_type = IEC61937_MPEG2_AAC_LSF_2048;
360
        break;
361
    case 4:
362
        ctx->data_type = IEC61937_MPEG2_AAC_LSF_4096;
363
        break;
364
    default:
365
        av_log(s, AV_LOG_ERROR, "%i samples in AAC frame not supported\n",
366
               hdr.samples);
367
        return AVERROR(EINVAL);
368
    }
369
    //TODO Data type dependent info (LC profile/SBR)
370
    return 0;
371
}
372

    
373

    
374
/*
375
 * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
376
 * they can be encapsulated in IEC 61937.
377
 * Here we encapsulate 24 TrueHD frames in a single MAT frame, padding them
378
 * to achieve constant rate.
379
 * The actual format of a MAT frame is unknown, but the below seems to work.
380
 * However, it seems it is not actually necessary for the 24 TrueHD frames to
381
 * be in an exact alignment with the MAT frame.
382
 */
383
#define MAT_FRAME_SIZE          61424
384
#define TRUEHD_FRAME_OFFSET     2560
385
#define MAT_MIDDLE_CODE_OFFSET  -4
386

    
387
static int spdif_header_truehd(AVFormatContext *s, AVPacket *pkt)
388
{
389
    IEC61937Context *ctx = s->priv_data;
390
    int mat_code_length = 0;
391
    const char mat_end_code[16] = { 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11 };
392

    
393
    if (!ctx->hd_buf_count) {
394
        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 };
395
        mat_code_length = sizeof(mat_start_code) + BURST_HEADER_SIZE;
396
        memcpy(ctx->hd_buf, mat_start_code, sizeof(mat_start_code));
397

    
398
    } else if (ctx->hd_buf_count == 12) {
399
        const char mat_middle_code[12] = { 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0 };
400
        mat_code_length = sizeof(mat_middle_code) + MAT_MIDDLE_CODE_OFFSET;
401
        memcpy(&ctx->hd_buf[12 * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + MAT_MIDDLE_CODE_OFFSET],
402
               mat_middle_code, sizeof(mat_middle_code));
403
    }
404

    
405
    if (pkt->size > TRUEHD_FRAME_OFFSET - mat_code_length) {
406
        /* if such frames exist, we'd need some more complex logic to
407
         * distribute the TrueHD frames in the MAT frame */
408
        av_log(s, AV_LOG_ERROR, "TrueHD frame too big, %d bytes\n", pkt->size);
409
        av_log_ask_for_sample(s, NULL);
410
        return AVERROR_INVALIDDATA;
411
    }
412

    
413
    memcpy(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length],
414
           pkt->data, pkt->size);
415
    memset(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length + pkt->size],
416
           0, TRUEHD_FRAME_OFFSET - pkt->size - mat_code_length);
417

    
418
    if (++ctx->hd_buf_count < 24){
419
        ctx->pkt_offset = 0;
420
        return 0;
421
    }
422
    memcpy(&ctx->hd_buf[MAT_FRAME_SIZE - sizeof(mat_end_code)], mat_end_code, sizeof(mat_end_code));
423
    ctx->hd_buf_count = 0;
424

    
425
    ctx->data_type   = IEC61937_TRUEHD;
426
    ctx->pkt_offset  = 61440;
427
    ctx->out_buf     = ctx->hd_buf;
428
    ctx->out_bytes   = MAT_FRAME_SIZE;
429
    ctx->length_code = MAT_FRAME_SIZE;
430
    return 0;
431
}
432

    
433
static int spdif_write_header(AVFormatContext *s)
434
{
435
    IEC61937Context *ctx = s->priv_data;
436

    
437
    switch (s->streams[0]->codec->codec_id) {
438
    case CODEC_ID_AC3:
439
        ctx->header_info = spdif_header_ac3;
440
        break;
441
    case CODEC_ID_EAC3:
442
        ctx->header_info = spdif_header_eac3;
443
        break;
444
    case CODEC_ID_MP1:
445
    case CODEC_ID_MP2:
446
    case CODEC_ID_MP3:
447
        ctx->header_info = spdif_header_mpeg;
448
        break;
449
    case CODEC_ID_DTS:
450
        ctx->header_info = spdif_header_dts;
451
        break;
452
    case CODEC_ID_AAC:
453
        ctx->header_info = spdif_header_aac;
454
        break;
455
    case CODEC_ID_TRUEHD:
456
        ctx->header_info = spdif_header_truehd;
457
        ctx->hd_buf = av_malloc(MAT_FRAME_SIZE);
458
        if (!ctx->hd_buf)
459
            return AVERROR(ENOMEM);
460
        break;
461
    default:
462
        av_log(s, AV_LOG_ERROR, "codec not supported\n");
463
        return AVERROR_PATCHWELCOME;
464
    }
465
    return 0;
466
}
467

    
468
static int spdif_write_trailer(AVFormatContext *s)
469
{
470
    IEC61937Context *ctx = s->priv_data;
471
    av_freep(&ctx->buffer);
472
    av_freep(&ctx->hd_buf);
473
    return 0;
474
}
475

    
476
static av_always_inline void spdif_put_16(IEC61937Context *ctx,
477
                                          AVIOContext *pb, unsigned int val)
478
{
479
    if (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)
480
        avio_wb16(pb, val);
481
    else
482
        avio_wl16(pb, val);
483
}
484

    
485
static int spdif_write_packet(struct AVFormatContext *s, AVPacket *pkt)
486
{
487
    IEC61937Context *ctx = s->priv_data;
488
    int ret, padding;
489

    
490
    ctx->out_buf = pkt->data;
491
    ctx->out_bytes = pkt->size;
492
    ctx->length_code = FFALIGN(pkt->size, 2) << 3;
493
    ctx->use_preamble = 1;
494
    ctx->extra_bswap = 0;
495

    
496
    ret = ctx->header_info(s, pkt);
497
    if (ret < 0)
498
        return ret;
499
    if (!ctx->pkt_offset)
500
        return 0;
501

    
502
    padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;
503
    if (padding < 0) {
504
        av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
505
        return AVERROR(EINVAL);
506
    }
507

    
508
    if (ctx->use_preamble) {
509
        spdif_put_16(ctx, s->pb, SYNCWORD1);       //Pa
510
        spdif_put_16(ctx, s->pb, SYNCWORD2);       //Pb
511
        spdif_put_16(ctx, s->pb, ctx->data_type);  //Pc
512
        spdif_put_16(ctx, s->pb, ctx->length_code);//Pd
513
    }
514

    
515
    if (ctx->extra_bswap ^ (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)) {
516
    avio_write(s->pb, ctx->out_buf, ctx->out_bytes & ~1);
517
    } else {
518
    av_fast_malloc(&ctx->buffer, &ctx->buffer_size, ctx->out_bytes + FF_INPUT_BUFFER_PADDING_SIZE);
519
    if (!ctx->buffer)
520
        return AVERROR(ENOMEM);
521
    ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);
522
    avio_write(s->pb, ctx->buffer, ctx->out_bytes & ~1);
523
    }
524

    
525
    /* a final lone byte has to be MSB aligned */
526
    if (ctx->out_bytes & 1)
527
        spdif_put_16(ctx, s->pb, ctx->out_buf[ctx->out_bytes - 1] << 8);
528

    
529
    ffio_fill(s->pb, 0, padding);
530

    
531
    av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
532
           ctx->data_type, ctx->out_bytes, ctx->pkt_offset);
533

    
534
    put_flush_packet(s->pb);
535
    return 0;
536
}
537

    
538
AVOutputFormat ff_spdif_muxer = {
539
    "spdif",
540
    NULL_IF_CONFIG_SMALL("IEC 61937 (used on S/PDIF - IEC958)"),
541
    NULL,
542
    "spdif",
543
    sizeof(IEC61937Context),
544
    CODEC_ID_AC3,
545
    CODEC_ID_NONE,
546
    spdif_write_header,
547
    spdif_write_packet,
548
    spdif_write_trailer,
549
    .flags = AVFMT_NOTIMESTAMPS,
550
    .priv_class = &class,
551
};