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FFmpeg/libavformat/mpegenc.c

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/*
* MPEG1/2 muxer
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include "libavutil/attributes.h"
#include "libavutil/fifo.h"
#include "libavutil/log.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavcodec/put_bits.h"
#include "avformat.h"
#include "internal.h"
#include "mpeg.h"
#define MAX_PAYLOAD_SIZE 4096
#undef NDEBUG
#include <assert.h>
typedef struct PacketDesc {
int64_t pts;
int64_t dts;
int size;
int unwritten_size;
int flags;
struct PacketDesc *next;
} PacketDesc;
typedef struct {
AVFifoBuffer *fifo;
uint8_t id;
int max_buffer_size; /* in bytes */
int buffer_index;
PacketDesc *predecode_packet;
PacketDesc *premux_packet;
PacketDesc **next_packet;
int packet_number;
uint8_t lpcm_header[3];
int lpcm_align;
int bytes_to_iframe;
int align_iframe;
int64_t vobu_start_pts;
} StreamInfo;
typedef struct {
const AVClass *class;
int packet_size; /* required packet size */
int packet_number;
int pack_header_freq; /* frequency (in packets^-1) at which we send pack headers */
int system_header_freq;
int system_header_size;
int mux_rate; /* bitrate in units of 50 bytes/s */
/* stream info */
int audio_bound;
int video_bound;
int is_mpeg2;
int is_vcd;
int is_svcd;
int is_dvd;
int64_t last_scr; /* current system clock */
double vcd_padding_bitrate; // FIXME floats
int64_t vcd_padding_bytes_written;
int preload;
} MpegMuxContext;
extern AVOutputFormat ff_mpeg1vcd_muxer;
extern AVOutputFormat ff_mpeg2dvd_muxer;
extern AVOutputFormat ff_mpeg2svcd_muxer;
extern AVOutputFormat ff_mpeg2vob_muxer;
static int put_pack_header(AVFormatContext *ctx, uint8_t *buf,
int64_t timestamp)
{
MpegMuxContext *s = ctx->priv_data;
PutBitContext pb;
init_put_bits(&pb, buf, 128);
put_bits32(&pb, PACK_START_CODE);
if (s->is_mpeg2)
put_bits(&pb, 2, 0x1);
else
put_bits(&pb, 4, 0x2);
put_bits(&pb, 3, (uint32_t)((timestamp >> 30) & 0x07));
put_bits(&pb, 1, 1);
put_bits(&pb, 15, (uint32_t)((timestamp >> 15) & 0x7fff));
put_bits(&pb, 1, 1);
put_bits(&pb, 15, (uint32_t)((timestamp) & 0x7fff));
put_bits(&pb, 1, 1);
if (s->is_mpeg2)
/* clock extension */
put_bits(&pb, 9, 0);
put_bits(&pb, 1, 1);
put_bits(&pb, 22, s->mux_rate);
put_bits(&pb, 1, 1);
if (s->is_mpeg2) {
put_bits(&pb, 1, 1);
put_bits(&pb, 5, 0x1f); /* reserved */
put_bits(&pb, 3, 0); /* stuffing length */
}
flush_put_bits(&pb);
return put_bits_ptr(&pb) - pb.buf;
}
static int put_system_header(AVFormatContext *ctx, uint8_t *buf,
int only_for_stream_id)
{
MpegMuxContext *s = ctx->priv_data;
int size, i, private_stream_coded, id;
PutBitContext pb;
init_put_bits(&pb, buf, 128);
put_bits32(&pb, SYSTEM_HEADER_START_CODE);
put_bits(&pb, 16, 0);
put_bits(&pb, 1, 1);
/* maximum bit rate of the multiplexed stream */
put_bits(&pb, 22, s->mux_rate);
put_bits(&pb, 1, 1); /* marker */
if (s->is_vcd && only_for_stream_id == VIDEO_ID) {
/* This header applies only to the video stream
* (see VCD standard p. IV-7) */
put_bits(&pb, 6, 0);
} else
put_bits(&pb, 6, s->audio_bound);
if (s->is_vcd) {
/* see VCD standard, p. IV-7 */
put_bits(&pb, 1, 0);
put_bits(&pb, 1, 1);
} else {
put_bits(&pb, 1, 0); /* variable bitrate */
put_bits(&pb, 1, 0); /* non constrainted bit stream */
}
if (s->is_vcd || s->is_dvd) {
/* see VCD standard p IV-7 */
put_bits(&pb, 1, 1); /* audio locked */
put_bits(&pb, 1, 1); /* video locked */
} else {
put_bits(&pb, 1, 0); /* audio locked */
put_bits(&pb, 1, 0); /* video locked */
}
put_bits(&pb, 1, 1); /* marker */
if (s->is_vcd && (only_for_stream_id & 0xe0) == AUDIO_ID) {
/* This header applies only to the audio stream
* (see VCD standard p. IV-7) */
put_bits(&pb, 5, 0);
} else
put_bits(&pb, 5, s->video_bound);
if (s->is_dvd) {
put_bits(&pb, 1, 0); /* packet_rate_restriction_flag */
put_bits(&pb, 7, 0x7f); /* reserved byte */
} else
put_bits(&pb, 8, 0xff); /* reserved byte */
/* DVD-Video Stream_bound entries
* id (0xB9) video, maximum P-STD for stream 0xE0. (P-STD_buffer_bound_scale = 1)
* id (0xB8) audio, maximum P-STD for any MPEG audio (0xC0 to 0xC7) streams. If there are none set to 4096 (32x128). (P-STD_buffer_bound_scale = 0)
* id (0xBD) private stream 1 (audio other than MPEG and subpictures). (P-STD_buffer_bound_scale = 1)
* id (0xBF) private stream 2, NAV packs, set to 2x1024. */
if (s->is_dvd) {
int P_STD_max_video = 0;
int P_STD_max_mpeg_audio = 0;
int P_STD_max_mpeg_PS1 = 0;
for (i = 0; i < ctx->nb_streams; i++) {
StreamInfo *stream = ctx->streams[i]->priv_data;
id = stream->id;
if (id == 0xbd && stream->max_buffer_size > P_STD_max_mpeg_PS1) {
P_STD_max_mpeg_PS1 = stream->max_buffer_size;
} else if (id >= 0xc0 && id <= 0xc7 &&
stream->max_buffer_size > P_STD_max_mpeg_audio) {
P_STD_max_mpeg_audio = stream->max_buffer_size;
} else if (id == 0xe0 &&
stream->max_buffer_size > P_STD_max_video) {
P_STD_max_video = stream->max_buffer_size;
}
}
/* video */
put_bits(&pb, 8, 0xb9); /* stream ID */
put_bits(&pb, 2, 3);
put_bits(&pb, 1, 1);
put_bits(&pb, 13, P_STD_max_video / 1024);
/* audio */
if (P_STD_max_mpeg_audio == 0)
P_STD_max_mpeg_audio = 4096;
put_bits(&pb, 8, 0xb8); /* stream ID */
put_bits(&pb, 2, 3);
put_bits(&pb, 1, 0);
put_bits(&pb, 13, P_STD_max_mpeg_audio / 128);
/* private stream 1 */
put_bits(&pb, 8, 0xbd); /* stream ID */
put_bits(&pb, 2, 3);
put_bits(&pb, 1, 0);
put_bits(&pb, 13, P_STD_max_mpeg_PS1 / 128);
/* private stream 2 */
put_bits(&pb, 8, 0xbf); /* stream ID */
put_bits(&pb, 2, 3);
put_bits(&pb, 1, 1);
put_bits(&pb, 13, 2);
} else {
/* audio stream info */
private_stream_coded = 0;
for (i = 0; i < ctx->nb_streams; i++) {
StreamInfo *stream = ctx->streams[i]->priv_data;
/* For VCDs, only include the stream info for the stream
* that the pack which contains this system belongs to.
* (see VCD standard p. IV-7) */
if (!s->is_vcd || stream->id == only_for_stream_id ||
only_for_stream_id == 0) {
id = stream->id;
if (id < 0xc0) {
/* special case for private streams (AC-3 uses that) */
if (private_stream_coded)
continue;
private_stream_coded = 1;
id = 0xbd;
}
put_bits(&pb, 8, id); /* stream ID */
put_bits(&pb, 2, 3);
if (id < 0xe0) {
/* audio */
put_bits(&pb, 1, 0);
put_bits(&pb, 13, stream->max_buffer_size / 128);
} else {
/* video */
put_bits(&pb, 1, 1);
put_bits(&pb, 13, stream->max_buffer_size / 1024);
}
}
}
}
flush_put_bits(&pb);
size = put_bits_ptr(&pb) - pb.buf;
/* patch packet size */
buf[4] = (size - 6) >> 8;
buf[5] = (size - 6) & 0xff;
return size;
}
static int get_system_header_size(AVFormatContext *ctx)
{
int buf_index, i, private_stream_coded;
StreamInfo *stream;
MpegMuxContext *s = ctx->priv_data;
if (s->is_dvd)
return 18; // DVD-Video system headers are 18 bytes fixed length.
buf_index = 12;
private_stream_coded = 0;
for (i = 0; i < ctx->nb_streams; i++) {
stream = ctx->streams[i]->priv_data;
if (stream->id < 0xc0) {
if (private_stream_coded)
continue;
private_stream_coded = 1;
}
buf_index += 3;
}
return buf_index;
}
static av_cold int mpeg_mux_init(AVFormatContext *ctx)
{
MpegMuxContext *s = ctx->priv_data;
int bitrate, i, mpa_id, mpv_id, mps_id, ac3_id, dts_id, lpcm_id, j;
AVStream *st;
StreamInfo *stream;
int audio_bitrate;
int video_bitrate;
s->packet_number = 0;
s->is_vcd = (CONFIG_MPEG1VCD_MUXER && ctx->oformat == &ff_mpeg1vcd_muxer);
s->is_svcd = (CONFIG_MPEG2SVCD_MUXER && ctx->oformat == &ff_mpeg2svcd_muxer);
s->is_mpeg2 = ((CONFIG_MPEG2VOB_MUXER && ctx->oformat == &ff_mpeg2vob_muxer) ||
(CONFIG_MPEG2DVD_MUXER && ctx->oformat == &ff_mpeg2dvd_muxer) ||
(CONFIG_MPEG2SVCD_MUXER && ctx->oformat == &ff_mpeg2svcd_muxer));
s->is_dvd = (CONFIG_MPEG2DVD_MUXER && ctx->oformat == &ff_mpeg2dvd_muxer);
if (ctx->packet_size) {
if (ctx->packet_size < 20 || ctx->packet_size > (1 << 23) + 10) {
av_log(ctx, AV_LOG_ERROR, "Invalid packet size %d\n",
ctx->packet_size);
goto fail;
}
s->packet_size = ctx->packet_size;
} else
s->packet_size = 2048;
if (ctx->max_delay < 0) /* Not set by the caller */
ctx->max_delay = 0;
s->vcd_padding_bytes_written = 0;
s->vcd_padding_bitrate = 0;
s->audio_bound = 0;
s->video_bound = 0;
mpa_id = AUDIO_ID;
ac3_id = AC3_ID;
dts_id = DTS_ID;
mpv_id = VIDEO_ID;
mps_id = SUB_ID;
lpcm_id = LPCM_ID;
for (i = 0; i < ctx->nb_streams; i++) {
st = ctx->streams[i];
stream = av_mallocz(sizeof(StreamInfo));
if (!stream)
goto fail;
st->priv_data = stream;
avpriv_set_pts_info(st, 64, 1, 90000);
switch (st->codec->codec_type) {
case AVMEDIA_TYPE_AUDIO:
if (st->codec->codec_id == AV_CODEC_ID_AC3) {
stream->id = ac3_id++;
} else if (st->codec->codec_id == AV_CODEC_ID_DTS) {
stream->id = dts_id++;
} else if (st->codec->codec_id == AV_CODEC_ID_PCM_S16BE) {
stream->id = lpcm_id++;
for (j = 0; j < 4; j++) {
if (lpcm_freq_tab[j] == st->codec->sample_rate)
break;
}
if (j == 4)
goto fail;
if (st->codec->channels > 8)
return -1;
stream->lpcm_header[0] = 0x0c;
stream->lpcm_header[1] = (st->codec->channels - 1) | (j << 4);
stream->lpcm_header[2] = 0x80;
stream->lpcm_align = st->codec->channels * 2;
} else {
stream->id = mpa_id++;
}
/* This value HAS to be used for VCD (see VCD standard, p. IV-7).
* Right now it is also used for everything else. */
stream->max_buffer_size = 4 * 1024;
s->audio_bound++;
break;
case AVMEDIA_TYPE_VIDEO:
stream->id = mpv_id++;
if (st->codec->rc_buffer_size)
stream->max_buffer_size = 6 * 1024 + st->codec->rc_buffer_size / 8;
else {
av_log(ctx, AV_LOG_WARNING,
"VBV buffer size not set, muxing may fail\n");
// FIXME: this is probably too small as default
stream->max_buffer_size = 230 * 1024;
}
s->video_bound++;
break;
case AVMEDIA_TYPE_SUBTITLE:
stream->id = mps_id++;
stream->max_buffer_size = 16 * 1024;
break;
default:
return -1;
}
stream->fifo = av_fifo_alloc(16);
if (!stream->fifo)
goto fail;
}
bitrate = 0;
audio_bitrate = 0;
video_bitrate = 0;
for (i = 0; i < ctx->nb_streams; i++) {
int codec_rate;
st = ctx->streams[i];
stream = (StreamInfo *)st->priv_data;
if (st->codec->rc_max_rate || stream->id == VIDEO_ID)
codec_rate = st->codec->rc_max_rate;
else
codec_rate = st->codec->bit_rate;
if (!codec_rate)
codec_rate = (1 << 21) * 8 * 50 / ctx->nb_streams;
bitrate += codec_rate;
if ((stream->id & 0xe0) == AUDIO_ID)
audio_bitrate += codec_rate;
else if (stream->id == VIDEO_ID)
video_bitrate += codec_rate;
}
if (!s->mux_rate) {
/* we increase slightly the bitrate to take into account the
* headers. XXX: compute it exactly */
bitrate += bitrate / 20;
bitrate += 10000;
s->mux_rate = (bitrate + (8 * 50) - 1) / (8 * 50);
}
if (s->is_vcd) {
double overhead_rate;
/* The VCD standard mandates that the mux_rate field is 3528
* (see standard p. IV-6).
* The value is actually "wrong", i.e. if you calculate
* it using the normal formula and the 75 sectors per second transfer
* rate you get a different value because the real pack size is 2324,
* not 2352. But the standard explicitly specifies that the mux_rate
* field in the header must have this value. */
// s->mux_rate = 2352 * 75 / 50; /* = 3528 */
/* The VCD standard states that the muxed stream must be
* exactly 75 packs / second (the data rate of a single speed cdrom).
* Since the video bitrate (probably 1150000 bits/sec) will be below
* the theoretical maximum we have to add some padding packets
* to make up for the lower data rate.
* (cf. VCD standard p. IV-6 ) */
/* Add the header overhead to the data rate.
* 2279 data bytes per audio pack, 2294 data bytes per video pack */
overhead_rate = ((audio_bitrate / 8.0) / 2279) * (2324 - 2279);
overhead_rate += ((video_bitrate / 8.0) / 2294) * (2324 - 2294);
overhead_rate *= 8;
/* Add padding so that the full bitrate is 2324*75 bytes/sec */
s->vcd_padding_bitrate = 2324 * 75 * 8 - (bitrate + overhead_rate);
}
if (s->is_vcd || s->is_mpeg2)
/* every packet */
s->pack_header_freq = 1;
else
/* every 2 seconds */
s->pack_header_freq = 2 * bitrate / s->packet_size / 8;
/* the above seems to make pack_header_freq zero sometimes */
if (s->pack_header_freq == 0)
s->pack_header_freq = 1;
if (s->is_mpeg2)
/* every 200 packets. Need to look at the spec. */
s->system_header_freq = s->pack_header_freq * 40;
else if (s->is_vcd)
/* the standard mandates that there are only two system headers
* in the whole file: one in the first packet of each stream.
* (see standard p. IV-7 and IV-8) */
s->system_header_freq = 0x7fffffff;
else
s->system_header_freq = s->pack_header_freq * 5;
for (i = 0; i < ctx->nb_streams; i++) {
stream = ctx->streams[i]->priv_data;
stream->packet_number = 0;
}
s->system_header_size = get_system_header_size(ctx);
s->last_scr = 0;
return 0;
fail:
for (i = 0; i < ctx->nb_streams; i++)
av_free(ctx->streams[i]->priv_data);
return AVERROR(ENOMEM);
}
static inline void put_timestamp(AVIOContext *pb, int id, int64_t timestamp)
{
avio_w8(pb, (id << 4) | (((timestamp >> 30) & 0x07) << 1) | 1);
avio_wb16(pb, (uint16_t)((((timestamp >> 15) & 0x7fff) << 1) | 1));
avio_wb16(pb, (uint16_t)((((timestamp) & 0x7fff) << 1) | 1));
}
/* return the number of padding bytes that should be inserted into
* the multiplexed stream. */
static int get_vcd_padding_size(AVFormatContext *ctx, int64_t pts)
{
MpegMuxContext *s = ctx->priv_data;
int pad_bytes = 0;
if (s->vcd_padding_bitrate > 0 && pts != AV_NOPTS_VALUE) {
int64_t full_pad_bytes;
// FIXME: this is wrong
full_pad_bytes =
(int64_t)((s->vcd_padding_bitrate * (pts / 90000.0)) / 8.0);
pad_bytes = (int)(full_pad_bytes - s->vcd_padding_bytes_written);
if (pad_bytes < 0)
/* might happen if we have already padded to a later timestamp. This
* can occur if another stream has already advanced further. */
pad_bytes = 0;
}
return pad_bytes;
}
/* Write an MPEG padding packet header. */
static void put_padding_packet(AVFormatContext *ctx, AVIOContext *pb,
int packet_bytes)
{
MpegMuxContext *s = ctx->priv_data;
int i;
avio_wb32(pb, PADDING_STREAM);
avio_wb16(pb, packet_bytes - 6);
if (!s->is_mpeg2) {
avio_w8(pb, 0x0f);
packet_bytes -= 7;
} else
packet_bytes -= 6;
for (i = 0; i < packet_bytes; i++)
avio_w8(pb, 0xff);
}
static int get_nb_frames(AVFormatContext *ctx, StreamInfo *stream, int len)
{
int nb_frames = 0;
PacketDesc *pkt_desc = stream->premux_packet;
while (len > 0) {
if (pkt_desc->size == pkt_desc->unwritten_size)
nb_frames++;
len -= pkt_desc->unwritten_size;
pkt_desc = pkt_desc->next;
}
return nb_frames;
}
/* flush the packet on stream stream_index */
static int flush_packet(AVFormatContext *ctx, int stream_index,
int64_t pts, int64_t dts, int64_t scr, int trailer_size)
{
MpegMuxContext *s = ctx->priv_data;
StreamInfo *stream = ctx->streams[stream_index]->priv_data;
uint8_t *buf_ptr;
int size, payload_size, startcode, id, stuffing_size, i, header_len;
int packet_size;
uint8_t buffer[128];
int zero_trail_bytes = 0;
int pad_packet_bytes = 0;
int pes_flags;
/* "general" pack without data specific to one stream? */
int general_pack = 0;
int nb_frames;
id = stream->id;
av_dlog(ctx, "packet ID=%2x PTS=%0.3f\n", id, pts / 90000.0);
buf_ptr = buffer;
if ((s->packet_number % s->pack_header_freq) == 0 || s->last_scr != scr) {
/* output pack and systems header if needed */
size = put_pack_header(ctx, buf_ptr, scr);
buf_ptr += size;
s->last_scr = scr;
if (s->is_vcd) {
/* there is exactly one system header for each stream in a VCD MPEG,
* One in the very first video packet and one in the very first
* audio packet (see VCD standard p. IV-7 and IV-8). */
if (stream->packet_number == 0) {
size = put_system_header(ctx, buf_ptr, id);
buf_ptr += size;
}
} else if (s->is_dvd) {
if (stream->align_iframe || s->packet_number == 0) {
int PES_bytes_to_fill = s->packet_size - size - 10;
if (pts != AV_NOPTS_VALUE) {
if (dts != pts)
PES_bytes_to_fill -= 5 + 5;
else
PES_bytes_to_fill -= 5;
}
if (stream->bytes_to_iframe == 0 || s->packet_number == 0) {
size = put_system_header(ctx, buf_ptr, 0);
buf_ptr += size;
size = buf_ptr - buffer;
avio_write(ctx->pb, buffer, size);
avio_wb32(ctx->pb, PRIVATE_STREAM_2);
avio_wb16(ctx->pb, 0x03d4); // length
avio_w8(ctx->pb, 0x00); // substream ID, 00=PCI
for (i = 0; i < 979; i++)
avio_w8(ctx->pb, 0x00);
avio_wb32(ctx->pb, PRIVATE_STREAM_2);
avio_wb16(ctx->pb, 0x03fa); // length
avio_w8(ctx->pb, 0x01); // substream ID, 01=DSI
for (i = 0; i < 1017; i++)
avio_w8(ctx->pb, 0x00);
memset(buffer, 0, 128);
buf_ptr = buffer;
s->packet_number++;
stream->align_iframe = 0;
// FIXME: rounding and first few bytes of each packet
scr += s->packet_size * 90000LL /
(s->mux_rate * 50LL);
size = put_pack_header(ctx, buf_ptr, scr);
s->last_scr = scr;
buf_ptr += size;
/* GOP Start */
} else if (stream->bytes_to_iframe < PES_bytes_to_fill) {
pad_packet_bytes = PES_bytes_to_fill -
stream->bytes_to_iframe;
}
}
} else {
if ((s->packet_number % s->system_header_freq) == 0) {
size = put_system_header(ctx, buf_ptr, 0);
buf_ptr += size;
}
}
}
size = buf_ptr - buffer;
avio_write(ctx->pb, buffer, size);
packet_size = s->packet_size - size;
if (s->is_vcd && (id & 0xe0) == AUDIO_ID)
/* The VCD standard demands that 20 zero bytes follow
* each audio pack (see standard p. IV-8). */
zero_trail_bytes += 20;
if ((s->is_vcd && stream->packet_number == 0) ||
(s->is_svcd && s->packet_number == 0)) {
/* for VCD the first pack of each stream contains only the pack header,
* the system header and lots of padding (see VCD standard p. IV-6).
* In the case of an audio pack, 20 zero bytes are also added at
* the end. */
/* For SVCD we fill the very first pack to increase compatibility with
* some DVD players. Not mandated by the standard. */
if (s->is_svcd)
/* the system header refers to both streams and no stream data */
general_pack = 1;
pad_packet_bytes = packet_size - zero_trail_bytes;
}
packet_size -= pad_packet_bytes + zero_trail_bytes;
if (packet_size > 0) {
/* packet header size */
packet_size -= 6;
/* packet header */
if (s->is_mpeg2) {
header_len = 3;
if (stream->packet_number == 0)
header_len += 3; /* PES extension */
header_len += 1; /* obligatory stuffing byte */
} else {
header_len = 0;
}
if (pts != AV_NOPTS_VALUE) {
if (dts != pts)
header_len += 5 + 5;
else
header_len += 5;
} else {
if (!s->is_mpeg2)
header_len++;
}
payload_size = packet_size - header_len;
if (id < 0xc0) {
startcode = PRIVATE_STREAM_1;
payload_size -= 1;
if (id >= 0x40) {
payload_size -= 3;
if (id >= 0xa0)
payload_size -= 3;
}
} else {
startcode = 0x100 + id;
}
stuffing_size = payload_size - av_fifo_size(stream->fifo);
// first byte does not fit -> reset pts/dts + stuffing
if (payload_size <= trailer_size && pts != AV_NOPTS_VALUE) {
int timestamp_len = 0;
if (dts != pts)
timestamp_len += 5;
if (pts != AV_NOPTS_VALUE)
timestamp_len += s->is_mpeg2 ? 5 : 4;
pts =
dts = AV_NOPTS_VALUE;
header_len -= timestamp_len;
if (s->is_dvd && stream->align_iframe) {
pad_packet_bytes += timestamp_len;
packet_size -= timestamp_len;
} else {
payload_size += timestamp_len;
}
stuffing_size += timestamp_len;
if (payload_size > trailer_size)
stuffing_size += payload_size - trailer_size;
}
// can't use padding, so use stuffing
if (pad_packet_bytes > 0 && pad_packet_bytes <= 7) {
packet_size += pad_packet_bytes;
payload_size += pad_packet_bytes; // undo the previous adjustment
if (stuffing_size < 0)
stuffing_size = pad_packet_bytes;
else
stuffing_size += pad_packet_bytes;
pad_packet_bytes = 0;
}
if (stuffing_size < 0)
stuffing_size = 0;
if (startcode == PRIVATE_STREAM_1 && id >= 0xa0) {
if (payload_size < av_fifo_size(stream->fifo))
stuffing_size += payload_size % stream->lpcm_align;
}
if (stuffing_size > 16) { /* <=16 for MPEG-1, <=32 for MPEG-2 */
pad_packet_bytes += stuffing_size;
packet_size -= stuffing_size;
payload_size -= stuffing_size;
stuffing_size = 0;
}
nb_frames = get_nb_frames(ctx, stream, payload_size - stuffing_size);
avio_wb32(ctx->pb, startcode);
avio_wb16(ctx->pb, packet_size);
if (!s->is_mpeg2)
for (i = 0; i < stuffing_size; i++)
avio_w8(ctx->pb, 0xff);
if (s->is_mpeg2) {
avio_w8(ctx->pb, 0x80); /* mpeg2 id */
pes_flags = 0;
if (pts != AV_NOPTS_VALUE) {
pes_flags |= 0x80;
if (dts != pts)
pes_flags |= 0x40;
}
/* Both the MPEG-2 and the SVCD standards demand that the
* P-STD_buffer_size field be included in the first packet of
* every stream. (see SVCD standard p. 26 V.2.3.1 and V.2.3.2
* and MPEG-2 standard 2.7.7) */
if (stream->packet_number == 0)
pes_flags |= 0x01;
avio_w8(ctx->pb, pes_flags); /* flags */
avio_w8(ctx->pb, header_len - 3 + stuffing_size);
if (pes_flags & 0x80) /* write pts */
put_timestamp(ctx->pb, (pes_flags & 0x40) ? 0x03 : 0x02, pts);
if (pes_flags & 0x40) /* write dts */
put_timestamp(ctx->pb, 0x01, dts);
if (pes_flags & 0x01) { /* write pes extension */
avio_w8(ctx->pb, 0x10); /* flags */
/* P-STD buffer info */
if ((id & 0xe0) == AUDIO_ID)
avio_wb16(ctx->pb, 0x4000 | stream->max_buffer_size / 128);
else
avio_wb16(ctx->pb, 0x6000 | stream->max_buffer_size / 1024);
}
} else {
if (pts != AV_NOPTS_VALUE) {
if (dts != pts) {
put_timestamp(ctx->pb, 0x03, pts);
put_timestamp(ctx->pb, 0x01, dts);
} else {
put_timestamp(ctx->pb, 0x02, pts);
}
} else {
avio_w8(ctx->pb, 0x0f);
}
}
if (s->is_mpeg2) {
/* special stuffing byte that is always written
* to prevent accidental generation of start codes. */
avio_w8(ctx->pb, 0xff);
for (i = 0; i < stuffing_size; i++)
avio_w8(ctx->pb, 0xff);
}
if (startcode == PRIVATE_STREAM_1) {
avio_w8(ctx->pb, id);
if (id >= 0xa0) {
/* LPCM (XXX: check nb_frames) */
avio_w8(ctx->pb, 7);
avio_wb16(ctx->pb, 4); /* skip 3 header bytes */
avio_w8(ctx->pb, stream->lpcm_header[0]);
avio_w8(ctx->pb, stream->lpcm_header[1]);
avio_w8(ctx->pb, stream->lpcm_header[2]);
} else if (id >= 0x40) {
/* AC-3 */
avio_w8(ctx->pb, nb_frames);
avio_wb16(ctx->pb, trailer_size + 1);
}
}
/* output data */
assert(payload_size - stuffing_size <= av_fifo_size(stream->fifo));
av_fifo_generic_read(stream->fifo, ctx->pb,
payload_size - stuffing_size,
(void (*)(void*, void*, int))avio_write);
stream->bytes_to_iframe -= payload_size - stuffing_size;
} else {
payload_size =
stuffing_size = 0;
}
if (pad_packet_bytes > 0)
put_padding_packet(ctx, ctx->pb, pad_packet_bytes);
for (i = 0; i < zero_trail_bytes; i++)
avio_w8(ctx->pb, 0x00);
avio_flush(ctx->pb);
s->packet_number++;
/* only increase the stream packet number if this pack actually contains
* something that is specific to this stream! I.e. a dedicated header
* or some data. */
if (!general_pack)
stream->packet_number++;
return payload_size - stuffing_size;
}
static void put_vcd_padding_sector(AVFormatContext *ctx)
{
/* There are two ways to do this padding: writing a sector/pack
* of 0 values, or writing an MPEG padding pack. Both seem to
* work with most decoders, BUT the VCD standard only allows a 0-sector
* (see standard p. IV-4, IV-5).
* So a 0-sector it is... */
MpegMuxContext *s = ctx->priv_data;
int i;
for (i = 0; i < s->packet_size; i++)
avio_w8(ctx->pb, 0);
s->vcd_padding_bytes_written += s->packet_size;
avio_flush(ctx->pb);
/* increasing the packet number is correct. The SCR of the following packs
* is calculated from the packet_number and it has to include the padding
* sector (it represents the sector index, not the MPEG pack index)
* (see VCD standard p. IV-6) */
s->packet_number++;
}
static int remove_decoded_packets(AVFormatContext *ctx, int64_t scr)
{
int i;
for (i = 0; i < ctx->nb_streams; i++) {
AVStream *st = ctx->streams[i];
StreamInfo *stream = st->priv_data;
PacketDesc *pkt_desc;
while ((pkt_desc = stream->predecode_packet) &&
scr > pkt_desc->dts) { // FIXME: > vs >=
if (stream->buffer_index < pkt_desc->size ||
stream->predecode_packet == stream->premux_packet) {
av_log(ctx, AV_LOG_ERROR,
"buffer underflow i=%d bufi=%d size=%d\n",
i, stream->buffer_index, pkt_desc->size);
break;
}
stream->buffer_index -= pkt_desc->size;
stream->predecode_packet = pkt_desc->next;
av_freep(&pkt_desc);
}
}
return 0;
}
static int output_packet(AVFormatContext *ctx, int flush)
{
MpegMuxContext *s = ctx->priv_data;
AVStream *st;
StreamInfo *stream;
int i, avail_space = 0, es_size, trailer_size;
int best_i = -1;
int best_score = INT_MIN;
int ignore_constraints = 0;
int64_t scr = s->last_scr;
PacketDesc *timestamp_packet;
const int64_t max_delay = av_rescale(ctx->max_delay, 90000, AV_TIME_BASE);
retry:
for (i = 0; i < ctx->nb_streams; i++) {
AVStream *st = ctx->streams[i];
StreamInfo *stream = st->priv_data;
const int avail_data = av_fifo_size(stream->fifo);
const int space = stream->max_buffer_size - stream->buffer_index;
int rel_space = 1024 * space / stream->max_buffer_size;
PacketDesc *next_pkt = stream->premux_packet;
/* for subtitle, a single PES packet must be generated,
* so we flush after every single subtitle packet */
if (s->packet_size > avail_data && !flush
&& st->codec->codec_type != AVMEDIA_TYPE_SUBTITLE)
return 0;
if (avail_data == 0)
continue;
assert(avail_data > 0);
if (space < s->packet_size && !ignore_constraints)
continue;
if (next_pkt && next_pkt->dts - scr > max_delay)
continue;
if (rel_space > best_score) {
best_score = rel_space;
best_i = i;
avail_space = space;
}
}
if (best_i < 0) {
int64_t best_dts = INT64_MAX;
for (i = 0; i < ctx->nb_streams; i++) {
AVStream *st = ctx->streams[i];
StreamInfo *stream = st->priv_data;
PacketDesc *pkt_desc = stream->predecode_packet;
if (pkt_desc && pkt_desc->dts < best_dts)
best_dts = pkt_desc->dts;
}
av_dlog(ctx, "bumping scr, scr:%f, dts:%f\n",
scr / 90000.0, best_dts / 90000.0);
if (best_dts == INT64_MAX)
return 0;
if (scr >= best_dts + 1 && !ignore_constraints) {
av_log(ctx, AV_LOG_ERROR,
"packet too large, ignoring buffer limits to mux it\n");
ignore_constraints = 1;
}
scr = FFMAX(best_dts + 1, scr);
if (remove_decoded_packets(ctx, scr) < 0)
return -1;
goto retry;
}
assert(best_i >= 0);
st = ctx->streams[best_i];
stream = st->priv_data;
assert(av_fifo_size(stream->fifo) > 0);
assert(avail_space >= s->packet_size || ignore_constraints);
timestamp_packet = stream->premux_packet;
if (timestamp_packet->unwritten_size == timestamp_packet->size) {
trailer_size = 0;
} else {
trailer_size = timestamp_packet->unwritten_size;
timestamp_packet = timestamp_packet->next;
}
if (timestamp_packet) {
av_dlog(ctx, "dts:%f pts:%f scr:%f stream:%d\n",
timestamp_packet->dts / 90000.0,
timestamp_packet->pts / 90000.0,
scr / 90000.0, best_i);
es_size = flush_packet(ctx, best_i, timestamp_packet->pts,
timestamp_packet->dts, scr, trailer_size);
} else {
assert(av_fifo_size(stream->fifo) == trailer_size);
es_size = flush_packet(ctx, best_i, AV_NOPTS_VALUE, AV_NOPTS_VALUE, scr,
trailer_size);
}
if (s->is_vcd) {
/* Write one or more padding sectors, if necessary, to reach
* the constant overall bitrate. */
int vcd_pad_bytes;
// FIXME: pts cannot be correct here
while ((vcd_pad_bytes = get_vcd_padding_size(ctx, stream->premux_packet->pts)) >= s->packet_size) {
put_vcd_padding_sector(ctx);
// FIXME: rounding and first few bytes of each packet
s->last_scr += s->packet_size * 90000LL / (s->mux_rate * 50LL);
}
}
stream->buffer_index += es_size;
// FIXME: rounding and first few bytes of each packet
s->last_scr += s->packet_size * 90000LL / (s->mux_rate * 50LL);
while (stream->premux_packet &&
stream->premux_packet->unwritten_size <= es_size) {
es_size -= stream->premux_packet->unwritten_size;
stream->premux_packet = stream->premux_packet->next;
}
if (es_size)
stream->premux_packet->unwritten_size -= es_size;
if (remove_decoded_packets(ctx, s->last_scr) < 0)
return -1;
return 1;
}
static int mpeg_mux_write_packet(AVFormatContext *ctx, AVPacket *pkt)
{
int stream_index = pkt->stream_index;
int size = pkt->size;
uint8_t *buf = pkt->data;
MpegMuxContext *s = ctx->priv_data;
AVStream *st = ctx->streams[stream_index];
StreamInfo *stream = st->priv_data;
int64_t pts, dts;
PacketDesc *pkt_desc;
int preload;
const int is_iframe = st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
(pkt->flags & AV_PKT_FLAG_KEY);
preload = av_rescale(s->preload, 90000, AV_TIME_BASE);
pts = pkt->pts;
dts = pkt->dts;
if (pts != AV_NOPTS_VALUE)
pts += 2 * preload;
if (dts != AV_NOPTS_VALUE) {
if (!s->last_scr)
s->last_scr = dts + preload;
dts += 2 * preload;
}
av_dlog(ctx, "dts:%f pts:%f flags:%d stream:%d nopts:%d\n",
dts / 90000.0, pts / 90000.0, pkt->flags,
pkt->stream_index, pts != AV_NOPTS_VALUE);
if (!stream->premux_packet)
stream->next_packet = &stream->premux_packet;
*stream->next_packet =
pkt_desc = av_mallocz(sizeof(PacketDesc));
pkt_desc->pts = pts;
pkt_desc->dts = dts;
pkt_desc->unwritten_size =
pkt_desc->size = size;
if (!stream->predecode_packet)
stream->predecode_packet = pkt_desc;
stream->next_packet = &pkt_desc->next;
if (av_fifo_realloc2(stream->fifo, av_fifo_size(stream->fifo) + size) < 0)
return -1;
if (s->is_dvd) {
// min VOBU length 0.4 seconds (mpucoder)
if (is_iframe &&
(s->packet_number == 0 ||
(pts - stream->vobu_start_pts >= 36000))) {
stream->bytes_to_iframe = av_fifo_size(stream->fifo);
stream->align_iframe = 1;
stream->vobu_start_pts = pts;
}
}
av_fifo_generic_write(stream->fifo, buf, size, NULL);
for (;;) {
int ret = output_packet(ctx, 0);
if (ret <= 0)
return ret;
}
}
static int mpeg_mux_end(AVFormatContext *ctx)
{
StreamInfo *stream;
int i;
for (;;) {
int ret = output_packet(ctx, 1);
if (ret < 0)
return ret;
else if (ret == 0)
break;
}
/* End header according to MPEG1 systems standard. We do not write
* it as it is usually not needed by decoders and because it
* complicates MPEG stream concatenation. */
// avio_wb32(ctx->pb, ISO_11172_END_CODE);
// avio_flush(ctx->pb);
for (i = 0; i < ctx->nb_streams; i++) {
stream = ctx->streams[i]->priv_data;
assert(av_fifo_size(stream->fifo) == 0);
av_fifo_free(stream->fifo);
}
return 0;
}
#define OFFSET(x) offsetof(MpegMuxContext, x)
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{ "muxrate", NULL, OFFSET(mux_rate), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, E },
{ "preload", "Initial demux-decode delay in microseconds.", OFFSET(preload), AV_OPT_TYPE_INT, { .i64 = 500000 }, 0, INT_MAX, E },
{ NULL },
};
#define MPEGENC_CLASS(flavor) \
static const AVClass flavor ## _class = { \
.class_name = #flavor " muxer", \
.item_name = av_default_item_name, \
.version = LIBAVUTIL_VERSION_INT, \
.option = options, \
};
#if CONFIG_MPEG1SYSTEM_MUXER
MPEGENC_CLASS(mpeg)
AVOutputFormat ff_mpeg1system_muxer = {
.name = "mpeg",
.long_name = NULL_IF_CONFIG_SMALL("MPEG-1 Systems / MPEG program stream"),
.mime_type = "video/mpeg",
.extensions = "mpg,mpeg",
.priv_data_size = sizeof(MpegMuxContext),
.audio_codec = AV_CODEC_ID_MP2,
.video_codec = AV_CODEC_ID_MPEG1VIDEO,
.write_header = mpeg_mux_init,
.write_packet = mpeg_mux_write_packet,
.write_trailer = mpeg_mux_end,
.priv_class = &mpeg_class,
};
#endif
#if CONFIG_MPEG1VCD_MUXER
MPEGENC_CLASS(vcd)
AVOutputFormat ff_mpeg1vcd_muxer = {
.name = "vcd",
.long_name = NULL_IF_CONFIG_SMALL("MPEG-1 Systems / MPEG program stream (VCD)"),
.mime_type = "video/mpeg",
.priv_data_size = sizeof(MpegMuxContext),
.audio_codec = AV_CODEC_ID_MP2,
.video_codec = AV_CODEC_ID_MPEG1VIDEO,
.write_header = mpeg_mux_init,
.write_packet = mpeg_mux_write_packet,
.write_trailer = mpeg_mux_end,
.priv_class = &vcd_class,
};
#endif
#if CONFIG_MPEG2VOB_MUXER
MPEGENC_CLASS(vob)
AVOutputFormat ff_mpeg2vob_muxer = {
.name = "vob",
.long_name = NULL_IF_CONFIG_SMALL("MPEG-2 PS (VOB)"),
.mime_type = "video/mpeg",
.extensions = "vob",
.priv_data_size = sizeof(MpegMuxContext),
.audio_codec = AV_CODEC_ID_MP2,
.video_codec = AV_CODEC_ID_MPEG2VIDEO,
.write_header = mpeg_mux_init,
.write_packet = mpeg_mux_write_packet,
.write_trailer = mpeg_mux_end,
.priv_class = &vob_class,
};
#endif
/* Same as mpeg2vob_mux except that the pack size is 2324 */
#if CONFIG_MPEG2SVCD_MUXER
MPEGENC_CLASS(svcd)
AVOutputFormat ff_mpeg2svcd_muxer = {
.name = "svcd",
.long_name = NULL_IF_CONFIG_SMALL("MPEG-2 PS (SVCD)"),
.mime_type = "video/mpeg",
.extensions = "vob",
.priv_data_size = sizeof(MpegMuxContext),
.audio_codec = AV_CODEC_ID_MP2,
.video_codec = AV_CODEC_ID_MPEG2VIDEO,
.write_header = mpeg_mux_init,
.write_packet = mpeg_mux_write_packet,
.write_trailer = mpeg_mux_end,
.priv_class = &svcd_class,
};
#endif
/* Same as mpeg2vob_mux except the 'is_dvd' flag is set to produce NAV pkts */
#if CONFIG_MPEG2DVD_MUXER
MPEGENC_CLASS(dvd)
AVOutputFormat ff_mpeg2dvd_muxer = {
.name = "dvd",
.long_name = NULL_IF_CONFIG_SMALL("MPEG-2 PS (DVD VOB)"),
.mime_type = "video/mpeg",
.extensions = "dvd",
.priv_data_size = sizeof(MpegMuxContext),
.audio_codec = AV_CODEC_ID_MP2,
.video_codec = AV_CODEC_ID_MPEG2VIDEO,
.write_header = mpeg_mux_init,
.write_packet = mpeg_mux_write_packet,
.write_trailer = mpeg_mux_end,
.priv_class = &dvd_class,
};
#endif