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FFmpeg/libavformat/spdifenc.c

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/*
* IEC 61937 muxer
* Copyright (c) 2009 Bartlomiej Wolowiec
* Copyright (c) 2010, 2020 Anssi Hannula
* Copyright (c) 2010 Carl Eugen Hoyos
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* IEC-61937 encapsulation of various formats, used by S/PDIF
* @author Bartlomiej Wolowiec
* @author Anssi Hannula
* @author Carl Eugen Hoyos
*/
/*
* Terminology used in specification:
* data-burst - IEC61937 frame, contains header and encapsuled frame
* burst-preamble - IEC61937 frame header, contains 16-bit words named Pa, Pb, Pc and Pd
* burst-payload - encapsuled frame
* Pa, Pb - syncword - 0xF872, 0x4E1F
* Pc - burst-info, contains data-type (bits 0-6), error flag (bit 7), data-type-dependent info (bits 8-12)
* and bitstream number (bits 13-15)
* data-type - determines type of encapsuled frames
* Pd - length code (number of bits or bytes of encapsuled frame - according to data_type)
*
* IEC 61937 frames at normal usage start every specific count of bytes,
* dependent from data-type (spaces between packets are filled by zeros)
*/
#include <inttypes.h>
#include "avformat.h"
#include "avio_internal.h"
#include "spdif.h"
#include "libavcodec/ac3defs.h"
#include "libavcodec/adts_parser.h"
#include "libavcodec/dca.h"
#include "libavcodec/dca_syncwords.h"
#include "libavutil/opt.h"
typedef struct IEC61937Context {
const AVClass *av_class;
enum IEC61937DataType data_type;///< burst info - reference to type of payload of the data-burst
int length_code; ///< length code in bits or bytes, depending on data type
int pkt_offset; ///< data burst repetition period in bytes
uint8_t *buffer; ///< allocated buffer, used for swap bytes
int buffer_size; ///< size of allocated buffer
uint8_t *out_buf; ///< pointer to the outgoing data before byte-swapping
int out_bytes; ///< amount of outgoing bytes
int use_preamble; ///< preamble enabled (disabled for exactly pre-padded DTS)
int extra_bswap; ///< extra bswap for payload (for LE DTS => standard BE DTS)
uint8_t *hd_buf[2]; ///< allocated buffers to concatenate hd audio frames
int hd_buf_size; ///< size of the hd audio buffer (eac3, dts4)
int hd_buf_count; ///< number of frames in the hd audio buffer (eac3)
int hd_buf_filled; ///< amount of bytes in the hd audio buffer (eac3, truehd)
int hd_buf_idx; ///< active hd buffer index (truehd)
int dtshd_skip; ///< counter used for skipping DTS-HD frames
uint16_t truehd_prev_time; ///< input_timing from the last frame
int truehd_prev_size; ///< previous frame size in bytes, including any MAT codes
int truehd_samples_per_frame; ///< samples per frame for padding calculation
/* AVOptions: */
int dtshd_rate;
int dtshd_fallback;
#define SPDIF_FLAG_BIGENDIAN 0x01
int spdif_flags;
/// function, which generates codec dependent header information.
/// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
int (*header_info) (AVFormatContext *s, AVPacket *pkt);
} IEC61937Context;
static const AVOption options[] = {
{ "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" },
{ "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" },
{ "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 },
{ "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 },
{ NULL },
};
static const AVClass spdif_class = {
.class_name = "spdif",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)
{
IEC61937Context *ctx = s->priv_data;
int bitstream_mode = pkt->data[5] & 0x7;
ctx->data_type = IEC61937_AC3 | (bitstream_mode << 8);
ctx->pkt_offset = AC3_FRAME_SIZE << 2;
return 0;
}
static int spdif_header_eac3(AVFormatContext *s, AVPacket *pkt)
{
IEC61937Context *ctx = s->priv_data;
static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
int repeat = 1;
uint8_t *tmp;
int bsid = pkt->data[5] >> 3;
if (bsid > 10 && (pkt->data[4] & 0xc0) != 0xc0) /* fscod */
repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */
tmp = av_fast_realloc(ctx->hd_buf[0], &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);
if (!tmp)
return AVERROR(ENOMEM);
ctx->hd_buf[0] = tmp;
memcpy(&ctx->hd_buf[0][ctx->hd_buf_filled], pkt->data, pkt->size);
ctx->hd_buf_filled += pkt->size;
if (++ctx->hd_buf_count < repeat){
ctx->pkt_offset = 0;
return 0;
}
ctx->data_type = IEC61937_EAC3;
ctx->pkt_offset = 24576;
ctx->out_buf = ctx->hd_buf[0];
ctx->out_bytes = ctx->hd_buf_filled;
ctx->length_code = ctx->hd_buf_filled;
ctx->hd_buf_count = 0;
ctx->hd_buf_filled = 0;
return 0;
}
/*
* DTS type IV (DTS-HD) can be transmitted with various frame repetition
* periods; longer repetition periods allow for longer packets and therefore
* higher bitrate. Longer repetition periods mean that the constant bitrate of
* the output IEC 61937 stream is higher.
* The repetition period is measured in IEC 60958 frames (4 bytes).
*/
static int spdif_dts4_subtype(int period)
{
switch (period) {
case 512: return 0x0;
case 1024: return 0x1;
case 2048: return 0x2;
case 4096: return 0x3;
case 8192: return 0x4;
case 16384: return 0x5;
}
return -1;
}
static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,
int sample_rate, int blocks)
{
IEC61937Context *ctx = s->priv_data;
static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
int pkt_size = pkt->size;
int period;
int subtype;
if (!core_size) {
av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");
return AVERROR(EINVAL);
}
if (!sample_rate) {
av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");
return AVERROR_INVALIDDATA;
}
period = ctx->dtshd_rate * (blocks << 5) / sample_rate;
subtype = spdif_dts4_subtype(period);
if (subtype < 0) {
av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "
"impossible repetition period of %d for the current DTS stream"
" (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,
blocks << 5, sample_rate);
return AVERROR(EINVAL);
}
/* set pkt_offset and DTS IV subtype according to the requested output
* rate */
ctx->pkt_offset = period * 4;
ctx->data_type = IEC61937_DTSHD | subtype << 8;
/* If the bitrate is too high for transmitting at the selected
* repetition period setting, strip DTS-HD until a good amount
* of consecutive non-overflowing HD frames have been observed.
* This generally only happens if the caller is cramming a Master
* Audio stream into 192kHz IEC 60958 (which may or may not fit). */
if (sizeof(dtshd_start_code) + 2 + pkt_size
> ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {
if (!ctx->dtshd_skip)
av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "
"temporarily sending core only\n");
if (ctx->dtshd_fallback > 0)
ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
else
/* skip permanently (dtshd_fallback == -1) or just once
* (dtshd_fallback == 0) */
ctx->dtshd_skip = 1;
}
if (ctx->dtshd_skip && core_size) {
pkt_size = core_size;
if (ctx->dtshd_fallback >= 0)
--ctx->dtshd_skip;
}
ctx->out_bytes = sizeof(dtshd_start_code) + 2 + pkt_size;
/* Align so that (length_code & 0xf) == 0x8. This is reportedly needed
* with some receivers, but the exact requirement is unconfirmed. */
ctx->length_code = FFALIGN(ctx->out_bytes + 0x8, 0x10) - 0x8;
av_fast_malloc(&ctx->hd_buf[0], &ctx->hd_buf_size, ctx->out_bytes);
if (!ctx->hd_buf[0])
return AVERROR(ENOMEM);
ctx->out_buf = ctx->hd_buf[0];
memcpy(ctx->hd_buf[0], dtshd_start_code, sizeof(dtshd_start_code));
AV_WB16(ctx->hd_buf[0] + sizeof(dtshd_start_code), pkt_size);
memcpy(ctx->hd_buf[0] + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);
return 0;
}
static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
{
IEC61937Context *ctx = s->priv_data;
uint32_t syncword_dts = AV_RB32(pkt->data);
int blocks;
int sample_rate = 0;
int core_size = 0;
if (pkt->size < 9)
return AVERROR_INVALIDDATA;
switch (syncword_dts) {
case DCA_SYNCWORD_CORE_BE:
blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;
sample_rate = ff_dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];
break;
case DCA_SYNCWORD_CORE_LE:
blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
ctx->extra_bswap = 1;
break;
case DCA_SYNCWORD_CORE_14B_BE:
blocks =
(((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
break;
case DCA_SYNCWORD_CORE_14B_LE:
blocks =
(((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
ctx->extra_bswap = 1;
break;
case DCA_SYNCWORD_SUBSTREAM:
/* We only handle HD frames that are paired with core. However,
sometimes DTS-HD streams with core have a stray HD frame without
core in the beginning of the stream. */
av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");
return AVERROR_INVALIDDATA;
default:
av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%"PRIx32"\n", syncword_dts);
return AVERROR_INVALIDDATA;
}
blocks++;
if (ctx->dtshd_rate)
/* DTS type IV output requested */
return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);
switch (blocks) {
case 512 >> 5: ctx->data_type = IEC61937_DTS1; break;
case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;
case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;
default:
av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
blocks << 5);
return AVERROR(ENOSYS);
}
/* discard extraneous data by default */
if (core_size && core_size < pkt->size) {
ctx->out_bytes = core_size;
ctx->length_code = core_size << 3;
}
ctx->pkt_offset = blocks << 7;
if (ctx->out_bytes == ctx->pkt_offset) {
/* The DTS stream fits exactly into the output stream, so skip the
* preamble as it would not fit in there. This is the case for dts
* discs and dts-in-wav. */
ctx->use_preamble = 0;
} else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {
avpriv_request_sample(s, "Unrecognized large DTS frame");
/* This will fail with a "bitrate too high" in the caller */
}
return 0;
}
static const enum IEC61937DataType mpeg_data_type[2][3] = {
// LAYER1 LAYER2 LAYER3
{ IEC61937_MPEG2_LAYER1_LSF, IEC61937_MPEG2_LAYER2_LSF, IEC61937_MPEG2_LAYER3_LSF }, // MPEG-2 LSF
{ IEC61937_MPEG1_LAYER1, IEC61937_MPEG1_LAYER23, IEC61937_MPEG1_LAYER23 }, // MPEG-1
};
static int spdif_header_mpeg(AVFormatContext *s, AVPacket *pkt)
{
IEC61937Context *ctx = s->priv_data;
int version = (pkt->data[1] >> 3) & 3;
int layer = 3 - ((pkt->data[1] >> 1) & 3);
int extension = pkt->data[2] & 1;
if (layer == 3 || version == 1) {
av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
return AVERROR_INVALIDDATA;
}
av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
if (version == 2 && extension) {
ctx->data_type = IEC61937_MPEG2_EXT;
ctx->pkt_offset = 4608;
} else {
ctx->data_type = mpeg_data_type [version & 1][layer];
ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];
}
// TODO Data type dependent info (normal/karaoke, dynamic range control)
return 0;
}
static int spdif_header_aac(AVFormatContext *s, AVPacket *pkt)
{
IEC61937Context *ctx = s->priv_data;
uint32_t samples;
uint8_t frames;
int ret;
ret = av_adts_header_parse(pkt->data, &samples, &frames);
if (ret < 0) {
av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
return ret;
}
ctx->pkt_offset = samples << 2;
switch (frames) {
case 1:
ctx->data_type = IEC61937_MPEG2_AAC;
break;
case 2:
ctx->data_type = IEC61937_MPEG2_AAC_LSF_2048;
break;
case 4:
ctx->data_type = IEC61937_MPEG2_AAC_LSF_4096;
break;
default:
av_log(s, AV_LOG_ERROR,
"%"PRIu32" samples in AAC frame not supported\n", samples);
return AVERROR(EINVAL);
}
//TODO Data type dependent info (LC profile/SBR)
return 0;
}
/*
* It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
* they can be encapsulated in IEC 61937.
*/
#define MAT_PKT_OFFSET 61440
#define MAT_FRAME_SIZE 61424
static const uint8_t mat_start_code[20] = {
0x07, 0x9E, 0x00, 0x03, 0x84, 0x01, 0x01, 0x01, 0x80, 0x00, 0x56, 0xA5, 0x3B, 0xF4, 0x81, 0x83,
0x49, 0x80, 0x77, 0xE0,
};
static const uint8_t mat_middle_code[12] = {
0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0,
};
static const uint8_t mat_end_code[16] = {
0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11,
};
#define MAT_CODE(position, data) { .pos = position, .code = data, .len = sizeof(data) }
static const struct {
unsigned int pos;
const uint8_t *code;
unsigned int len;
} mat_codes[] = {
MAT_CODE(0, mat_start_code),
MAT_CODE(30708, mat_middle_code),
MAT_CODE(MAT_FRAME_SIZE - sizeof(mat_end_code), mat_end_code),
};
static int spdif_header_truehd(AVFormatContext *s, AVPacket *pkt)
{
IEC61937Context *ctx = s->priv_data;
uint8_t *hd_buf = ctx->hd_buf[ctx->hd_buf_idx];
int ratebits;
int padding_remaining = 0;
uint16_t input_timing;
int total_frame_size = pkt->size;
const uint8_t *dataptr = pkt->data;
int data_remaining = pkt->size;
int have_pkt = 0;
int next_code_idx;
if (pkt->size < 10)
return AVERROR_INVALIDDATA;
if (AV_RB24(pkt->data + 4) == 0xf8726f) {
/* major sync unit, fetch sample rate */
if (pkt->data[7] == 0xba)
ratebits = pkt->data[8] >> 4;
else if (pkt->data[7] == 0xbb)
ratebits = pkt->data[9] >> 4;
else
return AVERROR_INVALIDDATA;
ctx->truehd_samples_per_frame = 40 << (ratebits & 3);
av_log(s, AV_LOG_TRACE, "TrueHD samples per frame: %d\n",
ctx->truehd_samples_per_frame);
}
if (!ctx->truehd_samples_per_frame)
return AVERROR_INVALIDDATA;
input_timing = AV_RB16(pkt->data + 2);
if (ctx->truehd_prev_size) {
uint16_t delta_samples = input_timing - ctx->truehd_prev_time;
/*
* One multiple-of-48kHz frame is 1/1200 sec and the IEC 61937 rate
* is 768kHz = 768000*4 bytes/sec.
* The nominal space per frame is therefore
* (768000*4 bytes/sec) * (1/1200 sec) = 2560 bytes.
* For multiple-of-44.1kHz frames: 1/1102.5 sec, 705.6kHz, 2560 bytes.
*
* 2560 is divisible by truehd_samples_per_frame.
*/
int delta_bytes = delta_samples * 2560 / ctx->truehd_samples_per_frame;
/* padding needed before this frame */
padding_remaining = delta_bytes - ctx->truehd_prev_size;
av_log(s, AV_LOG_TRACE, "delta_samples: %"PRIu16", delta_bytes: %d\n",
delta_samples, delta_bytes);
/* sanity check */
if (padding_remaining < 0 || padding_remaining >= MAT_FRAME_SIZE / 2) {
avpriv_request_sample(s, "Unusual frame timing: %"PRIu16" => %"PRIu16", %d samples/frame",
ctx->truehd_prev_time, input_timing, ctx->truehd_samples_per_frame);
padding_remaining = 0;
}
}
for (next_code_idx = 0; next_code_idx < FF_ARRAY_ELEMS(mat_codes); next_code_idx++)
if (ctx->hd_buf_filled <= mat_codes[next_code_idx].pos)
break;
if (next_code_idx >= FF_ARRAY_ELEMS(mat_codes))
return AVERROR_BUG;
while (padding_remaining || data_remaining ||
mat_codes[next_code_idx].pos == ctx->hd_buf_filled) {
if (mat_codes[next_code_idx].pos == ctx->hd_buf_filled) {
/* time to insert MAT code */
int code_len = mat_codes[next_code_idx].len;
int code_len_remaining = code_len;
memcpy(hd_buf + mat_codes[next_code_idx].pos,
mat_codes[next_code_idx].code, code_len);
ctx->hd_buf_filled += code_len;
next_code_idx++;
if (next_code_idx == FF_ARRAY_ELEMS(mat_codes)) {
next_code_idx = 0;
/* this was the last code, move to the next MAT frame */
have_pkt = 1;
ctx->out_buf = hd_buf;
ctx->hd_buf_idx ^= 1;
hd_buf = ctx->hd_buf[ctx->hd_buf_idx];
ctx->hd_buf_filled = 0;
/* inter-frame gap has to be counted as well, add it */
code_len_remaining += MAT_PKT_OFFSET - MAT_FRAME_SIZE;
}
if (padding_remaining) {
/* consider the MAT code as padding */
int counted_as_padding = FFMIN(padding_remaining,
code_len_remaining);
padding_remaining -= counted_as_padding;
code_len_remaining -= counted_as_padding;
}
/* count the remainder of the code as part of frame size */
if (code_len_remaining)
total_frame_size += code_len_remaining;
}
if (padding_remaining) {
int padding_to_insert = FFMIN(mat_codes[next_code_idx].pos - ctx->hd_buf_filled,
padding_remaining);
memset(hd_buf + ctx->hd_buf_filled, 0, padding_to_insert);
ctx->hd_buf_filled += padding_to_insert;
padding_remaining -= padding_to_insert;
if (padding_remaining)
continue; /* time to insert MAT code */
}
if (data_remaining) {
int data_to_insert = FFMIN(mat_codes[next_code_idx].pos - ctx->hd_buf_filled,
data_remaining);
memcpy(hd_buf + ctx->hd_buf_filled, dataptr, data_to_insert);
ctx->hd_buf_filled += data_to_insert;
dataptr += data_to_insert;
data_remaining -= data_to_insert;
}
}
ctx->truehd_prev_size = total_frame_size;
ctx->truehd_prev_time = input_timing;
av_log(s, AV_LOG_TRACE, "TrueHD frame inserted, total size %d, buffer position %d\n",
total_frame_size, ctx->hd_buf_filled);
if (!have_pkt) {
ctx->pkt_offset = 0;
return 0;
}
ctx->data_type = IEC61937_TRUEHD;
ctx->pkt_offset = MAT_PKT_OFFSET;
ctx->out_bytes = MAT_FRAME_SIZE;
ctx->length_code = MAT_FRAME_SIZE;
return 0;
}
static int spdif_write_header(AVFormatContext *s)
{
IEC61937Context *ctx = s->priv_data;
switch (s->streams[0]->codecpar->codec_id) {
case AV_CODEC_ID_AC3:
ctx->header_info = spdif_header_ac3;
break;
case AV_CODEC_ID_EAC3:
ctx->header_info = spdif_header_eac3;
break;
case AV_CODEC_ID_MP1:
case AV_CODEC_ID_MP2:
case AV_CODEC_ID_MP3:
ctx->header_info = spdif_header_mpeg;
break;
case AV_CODEC_ID_DTS:
ctx->header_info = spdif_header_dts;
break;
case AV_CODEC_ID_AAC:
ctx->header_info = spdif_header_aac;
break;
case AV_CODEC_ID_TRUEHD:
case AV_CODEC_ID_MLP:
ctx->header_info = spdif_header_truehd;
for (int i = 0; i < FF_ARRAY_ELEMS(ctx->hd_buf); i++) {
ctx->hd_buf[i] = av_malloc(MAT_FRAME_SIZE);
if (!ctx->hd_buf[i])
return AVERROR(ENOMEM);
}
break;
default:
avpriv_report_missing_feature(s, "Codec %d",
s->streams[0]->codecpar->codec_id);
return AVERROR_PATCHWELCOME;
}
return 0;
}
static void spdif_deinit(AVFormatContext *s)
{
IEC61937Context *ctx = s->priv_data;
av_freep(&ctx->buffer);
for (int i = 0; i < FF_ARRAY_ELEMS(ctx->hd_buf); i++)
av_freep(&ctx->hd_buf[i]);
}
static av_always_inline void spdif_put_16(IEC61937Context *ctx,
AVIOContext *pb, unsigned int val)
{
if (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)
avio_wb16(pb, val);
else
avio_wl16(pb, val);
}
static int spdif_write_packet(struct AVFormatContext *s, AVPacket *pkt)
{
IEC61937Context *ctx = s->priv_data;
int ret, padding;
ctx->out_buf = pkt->data;
ctx->out_bytes = pkt->size;
ctx->length_code = FFALIGN(pkt->size, 2) << 3;
ctx->use_preamble = 1;
ctx->extra_bswap = 0;
ret = ctx->header_info(s, pkt);
if (ret < 0)
return ret;
if (!ctx->pkt_offset)
return 0;
padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;
if (padding < 0) {
av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
return AVERROR(EINVAL);
}
if (ctx->use_preamble) {
spdif_put_16(ctx, s->pb, SYNCWORD1); //Pa
spdif_put_16(ctx, s->pb, SYNCWORD2); //Pb
spdif_put_16(ctx, s->pb, ctx->data_type); //Pc
spdif_put_16(ctx, s->pb, ctx->length_code);//Pd
}
if (ctx->extra_bswap ^ (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)) {
avio_write(s->pb, ctx->out_buf, ctx->out_bytes & ~1);
} else {
av_fast_malloc(&ctx->buffer, &ctx->buffer_size, ctx->out_bytes + AV_INPUT_BUFFER_PADDING_SIZE);
if (!ctx->buffer)
return AVERROR(ENOMEM);
ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);
avio_write(s->pb, ctx->buffer, ctx->out_bytes & ~1);
}
/* a final lone byte has to be MSB aligned */
if (ctx->out_bytes & 1)
spdif_put_16(ctx, s->pb, ctx->out_buf[ctx->out_bytes - 1] << 8);
ffio_fill(s->pb, 0, padding);
av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
ctx->data_type, ctx->out_bytes, ctx->pkt_offset);
return 0;
}
const AVOutputFormat ff_spdif_muxer = {
.name = "spdif",
.long_name = NULL_IF_CONFIG_SMALL("IEC 61937 (used on S/PDIF - IEC958)"),
.extensions = "spdif",
.priv_data_size = sizeof(IEC61937Context),
.audio_codec = AV_CODEC_ID_AC3,
.video_codec = AV_CODEC_ID_NONE,
.write_header = spdif_write_header,
.write_packet = spdif_write_packet,
.deinit = spdif_deinit,
.flags = AVFMT_NOTIMESTAMPS,
.priv_class = &spdif_class,
};