3 * Copyright (c) 2009 Bartlomiej Wolowiec
4 * Copyright (c) 2010, 2020 Anssi Hannula
5 * Copyright (c) 2010 Carl Eugen Hoyos
7 * This file is part of FFmpeg.
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26 * IEC-61937 encapsulation of various formats, used by S/PDIF
27 * @author Bartlomiej Wolowiec
28 * @author Anssi Hannula
29 * @author Carl Eugen Hoyos
33 * Terminology used in specification:
34 * data-burst - IEC61937 frame, contains header and encapsuled frame
35 * burst-preamble - IEC61937 frame header, contains 16-bit words named Pa, Pb, Pc and Pd
36 * burst-payload - encapsuled frame
37 * Pa, Pb - syncword - 0xF872, 0x4E1F
38 * Pc - burst-info, contains data-type (bits 0-6), error flag (bit 7), data-type-dependent info (bits 8-12)
39 * and bitstream number (bits 13-15)
40 * data-type - determines type of encapsuled frames
41 * Pd - length code (number of bits or bytes of encapsuled frame - according to data_type)
43 * IEC 61937 frames at normal usage start every specific count of bytes,
44 * dependent from data-type (spaces between packets are filled by zeros)
50 #include "avio_internal.h"
52 #include "libavcodec/ac3.h"
53 #include "libavcodec/adts_parser.h"
54 #include "libavcodec/dca.h"
55 #include "libavcodec/dca_syncwords.h"
56 #include "libavutil/opt.h"
58 typedef struct IEC61937Context {
59 const AVClass *av_class;
60 enum IEC61937DataType data_type;///< burst info - reference to type of payload of the data-burst
61 int length_code; ///< length code in bits or bytes, depending on data type
62 int pkt_offset; ///< data burst repetition period in bytes
63 uint8_t *buffer; ///< allocated buffer, used for swap bytes
64 int buffer_size; ///< size of allocated buffer
66 uint8_t *out_buf; ///< pointer to the outgoing data before byte-swapping
67 int out_bytes; ///< amount of outgoing bytes
69 int use_preamble; ///< preamble enabled (disabled for exactly pre-padded DTS)
70 int extra_bswap; ///< extra bswap for payload (for LE DTS => standard BE DTS)
72 uint8_t *hd_buf[2]; ///< allocated buffers to concatenate hd audio frames
73 int hd_buf_size; ///< size of the hd audio buffer (eac3, dts4)
74 int hd_buf_count; ///< number of frames in the hd audio buffer (eac3)
75 int hd_buf_filled; ///< amount of bytes in the hd audio buffer (eac3, truehd)
76 int hd_buf_idx; ///< active hd buffer index (truehd)
78 int dtshd_skip; ///< counter used for skipping DTS-HD frames
80 uint16_t truehd_prev_time; ///< input_timing from the last frame
81 int truehd_prev_size; ///< previous frame size in bytes, including any MAT codes
82 int truehd_samples_per_frame; ///< samples per frame for padding calculation
87 #define SPDIF_FLAG_BIGENDIAN 0x01
90 /// function, which generates codec dependent header information.
91 /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
92 int (*header_info) (AVFormatContext *s, AVPacket *pkt);
95 static const AVOption options[] = {
96 { "spdif_flags", "IEC 61937 encapsulation flags", offsetof(IEC61937Context, spdif_flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },
97 { "be", "output in big-endian format (for use as s16be)", 0, AV_OPT_TYPE_CONST, {.i64 = SPDIF_FLAG_BIGENDIAN}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },
98 { "dtshd_rate", "mux complete DTS frames in HD mode at the specified IEC958 rate (in Hz, default 0=disabled)", offsetof(IEC61937Context, dtshd_rate), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 768000, AV_OPT_FLAG_ENCODING_PARAM },
99 { "dtshd_fallback_time", "min secs to strip HD for after an overflow (-1: till the end, default 60)", offsetof(IEC61937Context, dtshd_fallback), AV_OPT_TYPE_INT, {.i64 = 60}, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
103 static const AVClass spdif_class = {
104 .class_name = "spdif",
105 .item_name = av_default_item_name,
107 .version = LIBAVUTIL_VERSION_INT,
110 static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)
112 IEC61937Context *ctx = s->priv_data;
113 int bitstream_mode = pkt->data[5] & 0x7;
115 ctx->data_type = IEC61937_AC3 | (bitstream_mode << 8);
116 ctx->pkt_offset = AC3_FRAME_SIZE << 2;
120 static int spdif_header_eac3(AVFormatContext *s, AVPacket *pkt)
122 IEC61937Context *ctx = s->priv_data;
123 static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
127 int bsid = pkt->data[5] >> 3;
128 if (bsid > 10 && (pkt->data[4] & 0xc0) != 0xc0) /* fscod */
129 repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */
131 tmp = av_fast_realloc(ctx->hd_buf[0], &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);
133 return AVERROR(ENOMEM);
134 ctx->hd_buf[0] = tmp;
136 memcpy(&ctx->hd_buf[0][ctx->hd_buf_filled], pkt->data, pkt->size);
138 ctx->hd_buf_filled += pkt->size;
139 if (++ctx->hd_buf_count < repeat){
143 ctx->data_type = IEC61937_EAC3;
144 ctx->pkt_offset = 24576;
145 ctx->out_buf = ctx->hd_buf[0];
146 ctx->out_bytes = ctx->hd_buf_filled;
147 ctx->length_code = ctx->hd_buf_filled;
149 ctx->hd_buf_count = 0;
150 ctx->hd_buf_filled = 0;
155 * DTS type IV (DTS-HD) can be transmitted with various frame repetition
156 * periods; longer repetition periods allow for longer packets and therefore
157 * higher bitrate. Longer repetition periods mean that the constant bitrate of
158 * the output IEC 61937 stream is higher.
159 * The repetition period is measured in IEC 60958 frames (4 bytes).
161 static int spdif_dts4_subtype(int period)
164 case 512: return 0x0;
165 case 1024: return 0x1;
166 case 2048: return 0x2;
167 case 4096: return 0x3;
168 case 8192: return 0x4;
169 case 16384: return 0x5;
174 static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,
175 int sample_rate, int blocks)
177 IEC61937Context *ctx = s->priv_data;
178 static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
179 int pkt_size = pkt->size;
184 av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");
185 return AVERROR(EINVAL);
189 av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");
190 return AVERROR_INVALIDDATA;
193 period = ctx->dtshd_rate * (blocks << 5) / sample_rate;
194 subtype = spdif_dts4_subtype(period);
197 av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "
198 "impossible repetition period of %d for the current DTS stream"
199 " (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,
200 blocks << 5, sample_rate);
201 return AVERROR(EINVAL);
204 /* set pkt_offset and DTS IV subtype according to the requested output
206 ctx->pkt_offset = period * 4;
207 ctx->data_type = IEC61937_DTSHD | subtype << 8;
209 /* If the bitrate is too high for transmitting at the selected
210 * repetition period setting, strip DTS-HD until a good amount
211 * of consecutive non-overflowing HD frames have been observed.
212 * This generally only happens if the caller is cramming a Master
213 * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
214 if (sizeof(dtshd_start_code) + 2 + pkt_size
215 > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {
216 if (!ctx->dtshd_skip)
217 av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "
218 "temporarily sending core only\n");
219 if (ctx->dtshd_fallback > 0)
220 ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
222 /* skip permanently (dtshd_fallback == -1) or just once
223 * (dtshd_fallback == 0) */
226 if (ctx->dtshd_skip && core_size) {
227 pkt_size = core_size;
228 if (ctx->dtshd_fallback >= 0)
232 ctx->out_bytes = sizeof(dtshd_start_code) + 2 + pkt_size;
234 /* Align so that (length_code & 0xf) == 0x8. This is reportedly needed
235 * with some receivers, but the exact requirement is unconfirmed. */
236 ctx->length_code = FFALIGN(ctx->out_bytes + 0x8, 0x10) - 0x8;
238 av_fast_malloc(&ctx->hd_buf[0], &ctx->hd_buf_size, ctx->out_bytes);
240 return AVERROR(ENOMEM);
242 ctx->out_buf = ctx->hd_buf[0];
244 memcpy(ctx->hd_buf[0], dtshd_start_code, sizeof(dtshd_start_code));
245 AV_WB16(ctx->hd_buf[0] + sizeof(dtshd_start_code), pkt_size);
246 memcpy(ctx->hd_buf[0] + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);
251 static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
253 IEC61937Context *ctx = s->priv_data;
254 uint32_t syncword_dts = AV_RB32(pkt->data);
260 return AVERROR_INVALIDDATA;
262 switch (syncword_dts) {
263 case DCA_SYNCWORD_CORE_BE:
264 blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
265 core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;
266 sample_rate = avpriv_dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];
268 case DCA_SYNCWORD_CORE_LE:
269 blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
270 ctx->extra_bswap = 1;
272 case DCA_SYNCWORD_CORE_14B_BE:
274 (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
276 case DCA_SYNCWORD_CORE_14B_LE:
278 (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
279 ctx->extra_bswap = 1;
281 case DCA_SYNCWORD_SUBSTREAM:
282 /* We only handle HD frames that are paired with core. However,
283 sometimes DTS-HD streams with core have a stray HD frame without
284 core in the beginning of the stream. */
285 av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");
286 return AVERROR_INVALIDDATA;
288 av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%"PRIx32"\n", syncword_dts);
289 return AVERROR_INVALIDDATA;
294 /* DTS type IV output requested */
295 return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);
298 case 512 >> 5: ctx->data_type = IEC61937_DTS1; break;
299 case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;
300 case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;
302 av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
304 return AVERROR(ENOSYS);
307 /* discard extraneous data by default */
308 if (core_size && core_size < pkt->size) {
309 ctx->out_bytes = core_size;
310 ctx->length_code = core_size << 3;
313 ctx->pkt_offset = blocks << 7;
315 if (ctx->out_bytes == ctx->pkt_offset) {
316 /* The DTS stream fits exactly into the output stream, so skip the
317 * preamble as it would not fit in there. This is the case for dts
318 * discs and dts-in-wav. */
319 ctx->use_preamble = 0;
320 } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {
321 avpriv_request_sample(s, "Unrecognized large DTS frame");
322 /* This will fail with a "bitrate too high" in the caller */
328 static const enum IEC61937DataType mpeg_data_type[2][3] = {
329 // LAYER1 LAYER2 LAYER3
330 { IEC61937_MPEG2_LAYER1_LSF, IEC61937_MPEG2_LAYER2_LSF, IEC61937_MPEG2_LAYER3_LSF }, // MPEG-2 LSF
331 { IEC61937_MPEG1_LAYER1, IEC61937_MPEG1_LAYER23, IEC61937_MPEG1_LAYER23 }, // MPEG-1
334 static int spdif_header_mpeg(AVFormatContext *s, AVPacket *pkt)
336 IEC61937Context *ctx = s->priv_data;
337 int version = (pkt->data[1] >> 3) & 3;
338 int layer = 3 - ((pkt->data[1] >> 1) & 3);
339 int extension = pkt->data[2] & 1;
341 if (layer == 3 || version == 1) {
342 av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
343 return AVERROR_INVALIDDATA;
345 av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
346 if (version == 2 && extension) {
347 ctx->data_type = IEC61937_MPEG2_EXT;
348 ctx->pkt_offset = 4608;
350 ctx->data_type = mpeg_data_type [version & 1][layer];
351 ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];
353 // TODO Data type dependent info (normal/karaoke, dynamic range control)
357 static int spdif_header_aac(AVFormatContext *s, AVPacket *pkt)
359 IEC61937Context *ctx = s->priv_data;
364 ret = av_adts_header_parse(pkt->data, &samples, &frames);
366 av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
370 ctx->pkt_offset = samples << 2;
373 ctx->data_type = IEC61937_MPEG2_AAC;
376 ctx->data_type = IEC61937_MPEG2_AAC_LSF_2048;
379 ctx->data_type = IEC61937_MPEG2_AAC_LSF_4096;
382 av_log(s, AV_LOG_ERROR,
383 "%"PRIu32" samples in AAC frame not supported\n", samples);
384 return AVERROR(EINVAL);
386 //TODO Data type dependent info (LC profile/SBR)
392 * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
393 * they can be encapsulated in IEC 61937.
395 #define MAT_PKT_OFFSET 61440
396 #define MAT_FRAME_SIZE 61424
398 static const uint8_t mat_start_code[20] = {
399 0x07, 0x9E, 0x00, 0x03, 0x84, 0x01, 0x01, 0x01, 0x80, 0x00, 0x56, 0xA5, 0x3B, 0xF4, 0x81, 0x83,
400 0x49, 0x80, 0x77, 0xE0,
402 static const uint8_t mat_middle_code[12] = {
403 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0,
405 static const uint8_t mat_end_code[16] = {
406 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11,
409 #define MAT_CODE(position, data) { .pos = position, .code = data, .len = sizeof(data) }
411 static const struct {
416 MAT_CODE(0, mat_start_code),
417 MAT_CODE(30708, mat_middle_code),
418 MAT_CODE(MAT_FRAME_SIZE - sizeof(mat_end_code), mat_end_code),
421 static int spdif_header_truehd(AVFormatContext *s, AVPacket *pkt)
423 IEC61937Context *ctx = s->priv_data;
424 uint8_t *hd_buf = ctx->hd_buf[ctx->hd_buf_idx];
426 int padding_remaining = 0;
427 uint16_t input_timing;
428 int total_frame_size = pkt->size;
429 const uint8_t *dataptr = pkt->data;
430 int data_remaining = pkt->size;
435 return AVERROR_INVALIDDATA;
437 if (AV_RB24(pkt->data + 4) == 0xf8726f) {
438 /* major sync unit, fetch sample rate */
439 if (pkt->data[7] == 0xba)
440 ratebits = pkt->data[8] >> 4;
441 else if (pkt->data[7] == 0xbb)
442 ratebits = pkt->data[9] >> 4;
444 return AVERROR_INVALIDDATA;
446 ctx->truehd_samples_per_frame = 40 << (ratebits & 3);
447 av_log(s, AV_LOG_TRACE, "TrueHD samples per frame: %d\n",
448 ctx->truehd_samples_per_frame);
451 if (!ctx->truehd_samples_per_frame)
452 return AVERROR_INVALIDDATA;
454 input_timing = AV_RB16(pkt->data + 2);
455 if (ctx->truehd_prev_size) {
456 uint16_t delta_samples = input_timing - ctx->truehd_prev_time;
458 * One multiple-of-48kHz frame is 1/1200 sec and the IEC 61937 rate
459 * is 768kHz = 768000*4 bytes/sec.
460 * The nominal space per frame is therefore
461 * (768000*4 bytes/sec) * (1/1200 sec) = 2560 bytes.
462 * For multiple-of-44.1kHz frames: 1/1102.5 sec, 705.6kHz, 2560 bytes.
464 * 2560 is divisible by truehd_samples_per_frame.
466 int delta_bytes = delta_samples * 2560 / ctx->truehd_samples_per_frame;
468 /* padding needed before this frame */
469 padding_remaining = delta_bytes - ctx->truehd_prev_size;
471 av_log(s, AV_LOG_TRACE, "delta_samples: %"PRIu16", delta_bytes: %d\n",
472 delta_samples, delta_bytes);
475 if (padding_remaining < 0 || padding_remaining >= MAT_FRAME_SIZE / 2) {
476 avpriv_request_sample(s, "Unusual frame timing: %"PRIu16" => %"PRIu16", %d samples/frame",
477 ctx->truehd_prev_time, input_timing, ctx->truehd_samples_per_frame);
478 padding_remaining = 0;
482 for (next_code_idx = 0; next_code_idx < FF_ARRAY_ELEMS(mat_codes); next_code_idx++)
483 if (ctx->hd_buf_filled <= mat_codes[next_code_idx].pos)
486 if (next_code_idx >= FF_ARRAY_ELEMS(mat_codes))
489 while (padding_remaining || data_remaining ||
490 mat_codes[next_code_idx].pos == ctx->hd_buf_filled) {
492 if (mat_codes[next_code_idx].pos == ctx->hd_buf_filled) {
493 /* time to insert MAT code */
494 int code_len = mat_codes[next_code_idx].len;
495 int code_len_remaining = code_len;
496 memcpy(hd_buf + mat_codes[next_code_idx].pos,
497 mat_codes[next_code_idx].code, code_len);
498 ctx->hd_buf_filled += code_len;
501 if (next_code_idx == FF_ARRAY_ELEMS(mat_codes)) {
504 /* this was the last code, move to the next MAT frame */
506 ctx->out_buf = hd_buf;
507 ctx->hd_buf_idx ^= 1;
508 hd_buf = ctx->hd_buf[ctx->hd_buf_idx];
509 ctx->hd_buf_filled = 0;
511 /* inter-frame gap has to be counted as well, add it */
512 code_len_remaining += MAT_PKT_OFFSET - MAT_FRAME_SIZE;
515 if (padding_remaining) {
516 /* consider the MAT code as padding */
517 int counted_as_padding = FFMIN(padding_remaining,
519 padding_remaining -= counted_as_padding;
520 code_len_remaining -= counted_as_padding;
522 /* count the remainder of the code as part of frame size */
523 if (code_len_remaining)
524 total_frame_size += code_len_remaining;
527 if (padding_remaining) {
528 int padding_to_insert = FFMIN(mat_codes[next_code_idx].pos - ctx->hd_buf_filled,
531 memset(hd_buf + ctx->hd_buf_filled, 0, padding_to_insert);
532 ctx->hd_buf_filled += padding_to_insert;
533 padding_remaining -= padding_to_insert;
535 if (padding_remaining)
536 continue; /* time to insert MAT code */
539 if (data_remaining) {
540 int data_to_insert = FFMIN(mat_codes[next_code_idx].pos - ctx->hd_buf_filled,
543 memcpy(hd_buf + ctx->hd_buf_filled, dataptr, data_to_insert);
544 ctx->hd_buf_filled += data_to_insert;
545 dataptr += data_to_insert;
546 data_remaining -= data_to_insert;
550 ctx->truehd_prev_size = total_frame_size;
551 ctx->truehd_prev_time = input_timing;
553 av_log(s, AV_LOG_TRACE, "TrueHD frame inserted, total size %d, buffer position %d\n",
554 total_frame_size, ctx->hd_buf_filled);
561 ctx->data_type = IEC61937_TRUEHD;
562 ctx->pkt_offset = MAT_PKT_OFFSET;
563 ctx->out_bytes = MAT_FRAME_SIZE;
564 ctx->length_code = MAT_FRAME_SIZE;
568 static int spdif_write_header(AVFormatContext *s)
570 IEC61937Context *ctx = s->priv_data;
572 switch (s->streams[0]->codecpar->codec_id) {
573 case AV_CODEC_ID_AC3:
574 ctx->header_info = spdif_header_ac3;
576 case AV_CODEC_ID_EAC3:
577 ctx->header_info = spdif_header_eac3;
579 case AV_CODEC_ID_MP1:
580 case AV_CODEC_ID_MP2:
581 case AV_CODEC_ID_MP3:
582 ctx->header_info = spdif_header_mpeg;
584 case AV_CODEC_ID_DTS:
585 ctx->header_info = spdif_header_dts;
587 case AV_CODEC_ID_AAC:
588 ctx->header_info = spdif_header_aac;
590 case AV_CODEC_ID_TRUEHD:
591 case AV_CODEC_ID_MLP:
592 ctx->header_info = spdif_header_truehd;
593 for (int i = 0; i < FF_ARRAY_ELEMS(ctx->hd_buf); i++) {
594 ctx->hd_buf[i] = av_malloc(MAT_FRAME_SIZE);
596 return AVERROR(ENOMEM);
600 avpriv_report_missing_feature(s, "Codec %d",
601 s->streams[0]->codecpar->codec_id);
602 return AVERROR_PATCHWELCOME;
607 static void spdif_deinit(AVFormatContext *s)
609 IEC61937Context *ctx = s->priv_data;
610 av_freep(&ctx->buffer);
611 for (int i = 0; i < FF_ARRAY_ELEMS(ctx->hd_buf); i++)
612 av_freep(&ctx->hd_buf[i]);
615 static av_always_inline void spdif_put_16(IEC61937Context *ctx,
616 AVIOContext *pb, unsigned int val)
618 if (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)
624 static int spdif_write_packet(struct AVFormatContext *s, AVPacket *pkt)
626 IEC61937Context *ctx = s->priv_data;
629 ctx->out_buf = pkt->data;
630 ctx->out_bytes = pkt->size;
631 ctx->length_code = FFALIGN(pkt->size, 2) << 3;
632 ctx->use_preamble = 1;
633 ctx->extra_bswap = 0;
635 ret = ctx->header_info(s, pkt);
638 if (!ctx->pkt_offset)
641 padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;
643 av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
644 return AVERROR(EINVAL);
647 if (ctx->use_preamble) {
648 spdif_put_16(ctx, s->pb, SYNCWORD1); //Pa
649 spdif_put_16(ctx, s->pb, SYNCWORD2); //Pb
650 spdif_put_16(ctx, s->pb, ctx->data_type); //Pc
651 spdif_put_16(ctx, s->pb, ctx->length_code);//Pd
654 if (ctx->extra_bswap ^ (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)) {
655 avio_write(s->pb, ctx->out_buf, ctx->out_bytes & ~1);
657 av_fast_malloc(&ctx->buffer, &ctx->buffer_size, ctx->out_bytes + AV_INPUT_BUFFER_PADDING_SIZE);
659 return AVERROR(ENOMEM);
660 ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);
661 avio_write(s->pb, ctx->buffer, ctx->out_bytes & ~1);
664 /* a final lone byte has to be MSB aligned */
665 if (ctx->out_bytes & 1)
666 spdif_put_16(ctx, s->pb, ctx->out_buf[ctx->out_bytes - 1] << 8);
668 ffio_fill(s->pb, 0, padding);
670 av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
671 ctx->data_type, ctx->out_bytes, ctx->pkt_offset);
676 AVOutputFormat ff_spdif_muxer = {
678 .long_name = NULL_IF_CONFIG_SMALL("IEC 61937 (used on S/PDIF - IEC958)"),
679 .extensions = "spdif",
680 .priv_data_size = sizeof(IEC61937Context),
681 .audio_codec = AV_CODEC_ID_AC3,
682 .video_codec = AV_CODEC_ID_NONE,
683 .write_header = spdif_write_header,
684 .write_packet = spdif_write_packet,
685 .deinit = spdif_deinit,
686 .flags = AVFMT_NOTIMESTAMPS,
687 .priv_class = &spdif_class,