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FFmpeg
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improved VCD support patch by ("Hauke Duden" <H.NS.Duden at gmx dot net>) 

- the first audio and video packs now contain only a system header and lots
  of padding.
  - no system headers in any packs other than the first ones
  - the two system headers only contain information about "their" stream
  - fixed some header values (muxrate, some flags, ...) so that they have the
  values specified by the standard
  - padding packs are inserted if the mux rate would be below 75 packs per
  second (the rate must not be below or above that value).
  - fixed the SCR of the packs
  - 20 zero bytes are now inserted at the end of each audio pack, after the
  data packet

Originally committed as revision 2804 to svn://svn.ffmpeg.org/ffmpeg/trunk
tags/v0.5
Hauke Duden Michael Niedermayer 22 years ago
parent
16806499fc
commit
2451592652
2 changed files with 452 additions and 143 deletions
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  1. +1
    -1
      ffmpeg.c
  2. +451
    -142
      libavformat/mpeg.c

+ 1
- 1
ffmpeg.c View File

@@ -3001,7 +3001,7 @@ static void opt_target(const char *arg)

opt_video_codec("mpeg2video");
opt_audio_codec("mp2");
opt_format("vcd");
opt_format("svcd");

opt_frame_size(norm ? "480x480" : "480x576");
opt_gop_size(norm ? "18" : "15");


+ 451
- 142
libavformat/mpeg.c View File

@@ -50,9 +50,14 @@ typedef struct {
int video_bound;
int is_mpeg2;
int is_vcd;
int is_svcd;
int scr_stream_index; /* stream from which the system clock is
computed (VBR case) */
int64_t last_scr; /* current system clock */

double vcd_padding_bitrate;
int64_t vcd_padding_bytes_written;

} MpegMuxContext;

#define PACK_START_CODE ((unsigned int)0x000001ba)
@@ -80,6 +85,7 @@ static const int lpcm_freq_tab[4] = { 48000, 96000, 44100, 32000 };
extern AVOutputFormat mpeg1system_mux;
extern AVOutputFormat mpeg1vcd_mux;
extern AVOutputFormat mpeg2vob_mux;
extern AVOutputFormat mpeg2svcd_mux;

static int put_pack_header(AVFormatContext *ctx,
uint8_t *buf, int64_t timestamp)
@@ -117,7 +123,7 @@ static int put_pack_header(AVFormatContext *ctx,
return pbBufPtr(&pb) - pb.buf;
}

static int put_system_header(AVFormatContext *ctx, uint8_t *buf)
static int put_system_header(AVFormatContext *ctx, uint8_t *buf,int only_for_stream_id)
{
MpegMuxContext *s = ctx->priv_data;
int size, rate_bound, i, private_stream_coded, id;
@@ -132,40 +138,67 @@ static int put_system_header(AVFormatContext *ctx, uint8_t *buf)
rate_bound = s->mux_rate; /* maximum bit rate of the multiplexed stream */
put_bits(&pb, 22, rate_bound);
put_bits(&pb, 1, 1); /* marker */
put_bits(&pb, 6, s->audio_bound);
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);

put_bits(&pb, 1, 1); /* variable bitrate */
if (s->is_vcd)
put_bits(&pb, 1, 0); /* see VCD standard, p. IV-7*/
else
put_bits(&pb, 1, 1); /* variable bitrate*/
put_bits(&pb, 1, 1); /* non constrainted bit stream */
put_bits(&pb, 1, 0); /* audio locked */
put_bits(&pb, 1, 0); /* video locked */
if (s->is_vcd) {
/* 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 */

put_bits(&pb, 5, s->video_bound);
if (s->is_vcd && only_for_stream_id==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);

put_bits(&pb, 8, 0xff); /* reserved byte */
/* audio stream info */
private_stream_coded = 0;
for(i=0;i<ctx->nb_streams;i++) {
StreamInfo *stream = ctx->streams[i]->priv_data;
id = stream->id;
if (id < 0xc0) {
/* special case for private streams (AC3 use 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);
/* 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 (AC3 use 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);
@@ -202,15 +235,21 @@ static int mpeg_mux_init(AVFormatContext *ctx)
int bitrate, i, mpa_id, mpv_id, ac3_id, lpcm_id, j;
AVStream *st;
StreamInfo *stream;
int audio_bitrate;
int video_bitrate;

s->packet_number = 0;
s->is_vcd = (ctx->oformat == &mpeg1vcd_mux);
s->is_mpeg2 = (ctx->oformat == &mpeg2vob_mux);
s->is_svcd = (ctx->oformat == &mpeg2svcd_mux);
s->is_mpeg2 = (ctx->oformat == &mpeg2vob_mux || ctx->oformat == &mpeg2svcd_mux);
if (s->is_vcd)
s->packet_size = 2324; /* VCD packet size */
if (s->is_vcd || s->is_svcd)
s->packet_size = 2324; /* VCD/SVCD packet size */
else
s->packet_size = 2048;

s->vcd_padding_bytes_written = 0;
s->vcd_padding_bitrate=0;
s->audio_bound = 0;
s->video_bound = 0;
@@ -266,14 +305,55 @@ static int mpeg_mux_init(AVFormatContext *ctx)
if (s->scr_stream_index == -1)
s->scr_stream_index = 0;

/* we increase slightly the bitrate to take into account the
headers. XXX: compute it exactly */
bitrate = 2000;
bitrate = 0;
audio_bitrate = 0;
video_bitrate = 0;
for(i=0;i<ctx->nb_streams;i++) {
st = ctx->streams[i];
stream = (StreamInfo*) st->priv_data;
bitrate += st->codec.bit_rate;

if (stream->id==AUDIO_ID)
audio_bitrate += st->codec.bit_rate;
else if (stream->id==VIDEO_ID)
video_bitrate += st->codec.bit_rate;
}

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);

} else {
/* we increase slightly the bitrate to take into account the
headers. XXX: compute it exactly */
bitrate += 2000;
s->mux_rate = (bitrate + (8 * 50) - 1) / (8 * 50);
}
s->mux_rate = (bitrate + (8 * 50) - 1) / (8 * 50);
if (s->is_vcd || s->is_mpeg2)
/* every packet */
@@ -290,8 +370,10 @@ static int mpeg_mux_init(AVFormatContext *ctx)
/* every 200 packets. Need to look at the spec. */
s->system_header_freq = s->pack_header_freq * 40;
else if (s->is_vcd)
/* every 40 packets, this is my invention */
s->system_header_freq = s->pack_header_freq * 40;
/* 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;
@@ -323,6 +405,30 @@ static inline void put_timestamp(ByteIOContext *pb, int id, int64_t timestamp)
}


/* 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;
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;
}


/* return the exact available payload size for the next packet for
stream 'stream_index'. 'pts' and 'dts' are only used to know if
timestamps are needed in the packet header. */
@@ -333,6 +439,8 @@ static int get_packet_payload_size(AVFormatContext *ctx, int stream_index,
int buf_index;
StreamInfo *stream;

stream = ctx->streams[stream_index]->priv_data;

buf_index = 0;
if (((s->packet_number % s->pack_header_freq) == 0)) {
/* pack header size */
@@ -340,41 +448,100 @@ static int get_packet_payload_size(AVFormatContext *ctx, int stream_index,
buf_index += 14;
else
buf_index += 12;
if ((s->packet_number % s->system_header_freq) == 0)
buf_index += s->system_header_size;
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)
/* The system headers refer only to the stream they occur in,
so they have a constant size.*/
buf_index += 15;

} else {
if ((s->packet_number % s->system_header_freq) == 0)
buf_index += s->system_header_size;
}
}

/* packet header size */
buf_index += 6;
if (s->is_mpeg2)
buf_index += 3;
if (pts != AV_NOPTS_VALUE) {
if (dts != pts)
buf_index += 5 + 5;
else
buf_index += 5;
} else {
if (!s->is_mpeg2)
buf_index++;
}
stream = ctx->streams[stream_index]->priv_data;
if (stream->id < 0xc0) {
/* AC3/LPCM private data header */
buf_index += 4;
if (stream->id >= 0xa0) {
int n;
if (s->is_vcd && stream->packet_number==0)
/* the first pack of each stream contains only the pack header,
the system header and some padding (see VCD standard p. IV-6)
Add the padding size, so that the actual payload becomes 0.*/
buf_index += s->packet_size - buf_index;
else {
/* packet header size */
buf_index += 6;
if (s->is_mpeg2)
buf_index += 3;
/* NOTE: we round the payload size to an integer number of
LPCM samples */
n = (s->packet_size - buf_index) % stream->lpcm_align;
if (n)
buf_index += (stream->lpcm_align - n);
if (pts != AV_NOPTS_VALUE) {
if (dts != pts)
buf_index += 5 + 5;
else
buf_index += 5;

} else {
if (!s->is_mpeg2)
buf_index++;
}
if (stream->id < 0xc0) {
/* AC3/LPCM private data header */
buf_index += 4;
if (stream->id >= 0xa0) {
int n;
buf_index += 3;
/* NOTE: we round the payload size to an integer number of
LPCM samples */
n = (s->packet_size - buf_index) % stream->lpcm_align;
if (n)
buf_index += (stream->lpcm_align - n);
}
}

if (s->is_vcd && stream->id == AUDIO_ID)
/* The VCD standard demands that 20 zero bytes follow
each audio packet (see standard p. IV-8).*/
buf_index+=20;
}
return s->packet_size - buf_index;
}

/* Write an MPEG padding packet header. */
static int put_padding_header(AVFormatContext *ctx,uint8_t* buf, int full_padding_size)
{
MpegMuxContext *s = ctx->priv_data;
int size = full_padding_size - 6; /* subtract header length */

buf[0] = (uint8_t)(PADDING_STREAM >> 24);
buf[1] = (uint8_t)(PADDING_STREAM >> 16);
buf[2] = (uint8_t)(PADDING_STREAM >> 8);
buf[3] = (uint8_t)(PADDING_STREAM);
buf[4] = (uint8_t)(size >> 8);
buf[5] = (uint8_t)(size & 0xff);

if (!s->is_mpeg2) {
buf[6] = 0x0f;
return 7;
} else
return 6;
}

static void put_padding_packet(AVFormatContext *ctx, ByteIOContext *pb,int packet_bytes)
{
uint8_t buffer[7];
int size, i;
size = put_padding_header(ctx,buffer, packet_bytes);
put_buffer(pb, buffer, size);
packet_bytes -= size;

for(i=0;i<packet_bytes;i++)
put_byte(pb, 0xff);
}


/* flush the packet on stream stream_index */
static void flush_packet(AVFormatContext *ctx, int stream_index,
int64_t pts, int64_t dts, int64_t scr)
@@ -385,6 +552,8 @@ static void flush_packet(AVFormatContext *ctx, int stream_index,
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;
id = stream->id;
@@ -394,109 +563,151 @@ static void flush_packet(AVFormatContext *ctx, int stream_index,
#endif

buf_ptr = buffer;

if (((s->packet_number % s->pack_header_freq) == 0)) {
/* output pack and systems header if needed */
size = put_pack_header(ctx, buf_ptr, scr);
buf_ptr += size;
if ((s->packet_number % s->system_header_freq) == 0) {
size = put_system_header(ctx, buf_ptr);
buf_ptr += size;

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->packet_number % s->system_header_freq) == 0) {
size = put_system_header(ctx, buf_ptr, 0);
buf_ptr += size;
}
}
}
size = buf_ptr - buffer;
put_buffer(&ctx->pb, buffer, size);

/* packet header */
if (s->is_mpeg2) {
header_len = 3;
} 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++;
packet_size = s->packet_size - size;

if (s->is_vcd && id == 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) {
/* 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.*/
pad_packet_bytes = packet_size - zero_trail_bytes;
}

packet_size = s->packet_size - (size + 6);
payload_size = packet_size - header_len;
if (id < 0xc0) {
startcode = PRIVATE_STREAM_1;
payload_size -= 4;
if (id >= 0xa0)
payload_size -= 3;
} else {
startcode = 0x100 + id;
}
packet_size -= pad_packet_bytes + zero_trail_bytes;

stuffing_size = payload_size - stream->buffer_ptr;
if (stuffing_size < 0)
stuffing_size = 0;
put_be32(&ctx->pb, startcode);
if (packet_size > 0) {

put_be16(&ctx->pb, packet_size);
/* packet header size */
packet_size -= 6;
/* packet header */
if (s->is_mpeg2) {
header_len = 3;
} 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++;
}

if (!s->is_mpeg2)
for(i=0;i<stuffing_size;i++)
put_byte(&ctx->pb, 0xff);
payload_size = packet_size - header_len;
if (id < 0xc0) {
startcode = PRIVATE_STREAM_1;
payload_size -= 4;
if (id >= 0xa0)
payload_size -= 3;
} else {
startcode = 0x100 + id;
}

if (s->is_mpeg2) {
put_byte(&ctx->pb, 0x80); /* mpeg2 id */
stuffing_size = payload_size - stream->buffer_ptr;
if (stuffing_size < 0)
stuffing_size = 0;
put_be32(&ctx->pb, startcode);

if (pts != AV_NOPTS_VALUE) {
if (dts != pts) {
put_byte(&ctx->pb, 0xc0); /* flags */
put_byte(&ctx->pb, header_len - 3 + stuffing_size);
put_timestamp(&ctx->pb, 0x03, pts);
put_timestamp(&ctx->pb, 0x01, dts);
put_be16(&ctx->pb, packet_size);
if (!s->is_mpeg2)
for(i=0;i<stuffing_size;i++)
put_byte(&ctx->pb, 0xff);

if (s->is_mpeg2) {
put_byte(&ctx->pb, 0x80); /* mpeg2 id */

if (pts != AV_NOPTS_VALUE) {
if (dts != pts) {
put_byte(&ctx->pb, 0xc0); /* flags */
put_byte(&ctx->pb, header_len - 3 + stuffing_size);
put_timestamp(&ctx->pb, 0x03, pts);
put_timestamp(&ctx->pb, 0x01, dts);
} else {
put_byte(&ctx->pb, 0x80); /* flags */
put_byte(&ctx->pb, header_len - 3 + stuffing_size);
put_timestamp(&ctx->pb, 0x02, pts);
}
} else {
put_byte(&ctx->pb, 0x80); /* flags */
put_byte(&ctx->pb, 0x00); /* flags */
put_byte(&ctx->pb, header_len - 3 + stuffing_size);
put_timestamp(&ctx->pb, 0x02, pts);
}
} else {
put_byte(&ctx->pb, 0x00); /* flags */
put_byte(&ctx->pb, header_len - 3 + stuffing_size);
}
} else {
if (pts != AV_NOPTS_VALUE) {
if (dts != pts) {
put_timestamp(&ctx->pb, 0x03, pts);
put_timestamp(&ctx->pb, 0x01, dts);
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 {
put_timestamp(&ctx->pb, 0x02, pts);
put_byte(&ctx->pb, 0x0f);
}
} else {
put_byte(&ctx->pb, 0x0f);
}
}

if (startcode == PRIVATE_STREAM_1) {
put_byte(&ctx->pb, id);
if (id >= 0xa0) {
/* LPCM (XXX: check nb_frames) */
put_byte(&ctx->pb, 7);
put_be16(&ctx->pb, 4); /* skip 3 header bytes */
put_byte(&ctx->pb, stream->lpcm_header[0]);
put_byte(&ctx->pb, stream->lpcm_header[1]);
put_byte(&ctx->pb, stream->lpcm_header[2]);
} else {
/* AC3 */
put_byte(&ctx->pb, stream->nb_frames);
put_be16(&ctx->pb, stream->frame_start_offset);
if (startcode == PRIVATE_STREAM_1) {
put_byte(&ctx->pb, id);
if (id >= 0xa0) {
/* LPCM (XXX: check nb_frames) */
put_byte(&ctx->pb, 7);
put_be16(&ctx->pb, 4); /* skip 3 header bytes */
put_byte(&ctx->pb, stream->lpcm_header[0]);
put_byte(&ctx->pb, stream->lpcm_header[1]);
put_byte(&ctx->pb, stream->lpcm_header[2]);
} else {
/* AC3 */
put_byte(&ctx->pb, stream->nb_frames);
put_be16(&ctx->pb, stream->frame_start_offset);
}
}

if (s->is_mpeg2)
for(i=0;i<stuffing_size;i++)
put_byte(&ctx->pb, 0xff);

/* output data */
put_buffer(&ctx->pb, stream->buffer, payload_size - stuffing_size);
}

if (s->is_mpeg2)
for(i=0;i<stuffing_size;i++)
put_byte(&ctx->pb, 0xff);
if (pad_packet_bytes > 0)
put_padding_packet(ctx,&ctx->pb, pad_packet_bytes);

/* output data */
put_buffer(&ctx->pb, stream->buffer, payload_size - stuffing_size);
for(i=0;i<zero_trail_bytes;i++)
put_byte(&ctx->pb, 0x00);
put_flush_packet(&ctx->pb);
s->packet_number++;
@@ -505,6 +716,31 @@ static void flush_packet(AVFormatContext *ctx, int stream_index,
stream->frame_start_offset = 0;
}

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++)
put_byte(&ctx->pb, 0);

s->vcd_padding_bytes_written += s->packet_size;
put_flush_packet(&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++;
}

/* XXX: move that to upper layer */
/* XXX: we assume that there are always 'max_b_frames' between
reference frames. A better solution would be to use the AVFrame pts
@@ -549,6 +785,43 @@ static void compute_pts_dts(AVStream *st, int64_t *ppts, int64_t *pdts,
*pdts = dts & ((1LL << 33) - 1);
}

static int64_t update_scr(AVFormatContext *ctx,int stream_index,int64_t pts)
{
MpegMuxContext *s = ctx->priv_data;
int64_t scr;

if (s->is_vcd)
/* Since the data delivery rate is constant, SCR is computed
using the formula C + i * 1200 where C is the start constant
and i is the pack index.
It is recommended that SCR 0 is at the beginning of the VCD front
margin (a sequence of empty Form 2 sectors on the CD).
It is recommended that the front margin is 30 sectors long, so
we use C = 30*1200 = 36000
(Note that even if the front margin is not 30 sectors the file
will still be correct according to the standard. It just won't have
the "recommended" value).*/
scr = 36000 + s->packet_number * 1200;
else {
/* XXX I believe this calculation of SCR is wrong. SCR
specifies at which time the data should enter the decoder.
Two packs cannot enter the decoder at the same time. */

/* XXX: system clock should be computed precisely, especially for
CBR case. The current mode gives at least something coherent */
if (stream_index == s->scr_stream_index
&& pts != AV_NOPTS_VALUE)
scr = pts;
else
scr = s->last_scr;
}

s->last_scr=scr;

return scr;
}


static int mpeg_mux_write_packet(AVFormatContext *ctx, int stream_index,
const uint8_t *buf, int size,
int64_t timestamp)
@@ -558,15 +831,13 @@ static int mpeg_mux_write_packet(AVFormatContext *ctx, int stream_index,
StreamInfo *stream = st->priv_data;
int64_t pts, dts, new_start_pts, new_start_dts;
int len, avail_size;
compute_pts_dts(st, &pts, &dts, timestamp);

/* XXX: system clock should be computed precisely, especially for
CBR case. The current mode gives at least something coherent */
if (stream_index == s->scr_stream_index)
s->last_scr = pts;
#if 0
update_scr(ctx,stream_index,pts);

printf("%d: pts=%0.3f dts=%0.3f scr=%0.3f\n",
stream_index,
pts / 90000.0,
@@ -586,10 +857,15 @@ static int mpeg_mux_write_packet(AVFormatContext *ctx, int stream_index,
new_start_pts,
new_start_dts);
if (stream->buffer_ptr >= avail_size) {

update_scr(ctx,stream_index,stream->start_pts);

/* unlikely case: outputing the pts or dts increase the packet
size so that we cannot write the start of the next
packet. In this case, we must flush the current packet with
padding */
padding.
Note: this always happens for the first audio and video packet
in a VCD file, since they do not carry any data.*/
flush_packet(ctx, stream_index,
stream->start_pts, stream->start_dts, s->last_scr);
stream->buffer_ptr = 0;
@@ -611,10 +887,23 @@ static int mpeg_mux_write_packet(AVFormatContext *ctx, int stream_index,
buf += len;
size -= len;
if (stream->buffer_ptr >= avail_size) {

update_scr(ctx,stream_index,stream->start_pts);

/* if packet full, we send it now */
flush_packet(ctx, stream_index,
stream->start_pts, stream->start_dts, s->last_scr);
stream->buffer_ptr = 0;

if (s->is_vcd) {
/* Write one or more padding sectors, if necessary, to reach
the constant overall bitrate.*/
int vcd_pad_bytes;
while((vcd_pad_bytes = get_vcd_padding_size(ctx,stream->start_pts) ) >= s->packet_size)
put_vcd_padding_sector(ctx);
}

/* Make sure only the FIRST pes packet for this frame has
a timestamp */
stream->start_pts = AV_NOPTS_VALUE;
@@ -635,6 +924,8 @@ static int mpeg_mux_end(AVFormatContext *ctx)
for(i=0;i<ctx->nb_streams;i++) {
stream = ctx->streams[i]->priv_data;
if (stream->buffer_ptr > 0) {
update_scr(ctx,i,stream->start_pts);

/* NOTE: we can always write the remaining data as it was
tested before in mpeg_mux_write_packet() */
flush_packet(ctx, i, stream->start_pts, stream->start_dts,
@@ -1139,7 +1430,7 @@ static int mpegps_read_seek(AVFormatContext *s,
start_pos= pos;

// read the next timestamp
dts = mpegps_read_dts(s, stream_index, &pos, 1);
dts = mpegps_read_dts(s, stream_index, &pos, 1);
if(pos == pos_max)
no_change++;
else
@@ -1214,6 +1505,23 @@ static AVOutputFormat mpeg2vob_mux = {
mpeg_mux_write_packet,
mpeg_mux_end,
};

/* Same as mpeg2vob_mux except that the pack size is 2324 */
static AVOutputFormat mpeg2svcd_mux = {
"svcd",
"MPEG2 PS format (VOB)",
"video/mpeg",
"vob",
sizeof(MpegMuxContext),
CODEC_ID_MP2,
CODEC_ID_MPEG2VIDEO,
mpeg_mux_init,
mpeg_mux_write_packet,
mpeg_mux_end,
};



#endif //CONFIG_ENCODERS

AVInputFormat mpegps_demux = {
@@ -1233,6 +1541,7 @@ int mpegps_init(void)
av_register_output_format(&mpeg1system_mux);
av_register_output_format(&mpeg1vcd_mux);
av_register_output_format(&mpeg2vob_mux);
av_register_output_format(&mpeg2svcd_mux);
#endif //CONFIG_ENCODERS
av_register_input_format(&mpegps_demux);
return 0;


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