[MPlayer-dev-eng] [PATCH] Timestamp-based mpg seeking
Michael Behrisch
behrisch at informatik.hu-berlin.de
Mon Oct 18 10:28:27 CEST 2004
On Sun, Oct 17, 2004 at 06:42:00PM +0200, Aurelien Jacobs wrote:
>
> There was a slight modifications on demux_mpg.c in cvs. Hence,
> your patch do not apply anymore. Could you please update it ?
> Then I will probably commit it in a few days if no one else do
> it or complain. This patch seem clean, works well and is really
> useful IMHO.
>
I updated the patch and also added some modifications which
improve seeking for files without valid timestamps. It might
be useful to add a command line switch to set the "precision"
value (maximum number of iterative searchs) because for some
files larger values (2 or 3) may be needed and for people
who like skimming through the file (holding their finger on
the "cursor right") precision=1 might already mean a
considerable slowdown.
However this will need another patch then.
Michael
-------------- next part --------------
Index: libmpdemux/demuxer.c
===================================================================
RCS file: /cvsroot/mplayer/main/libmpdemux/demuxer.c,v
retrieving revision 1.170
diff -u -r1.170 demuxer.c
--- libmpdemux/demuxer.c 8 Oct 2004 21:28:19 -0000 1.170
+++ libmpdemux/demuxer.c 18 Oct 2004 08:19:05 -0000
@@ -134,6 +134,7 @@
extern void demux_close_nuv(demuxer_t* demuxer);
extern void demux_close_audio(demuxer_t* demuxer);
extern void demux_close_ogg(demuxer_t* demuxer);
+extern void demux_close_mpg(demuxer_t* demuxer);
extern void demux_close_rtp(demuxer_t* demuxer);
extern void demux_close_demuxers(demuxer_t* demuxer);
extern void demux_close_avi(demuxer_t *demuxer);
@@ -232,6 +233,8 @@
case DEMUXER_TYPE_MPEG_TS:
case DEMUXER_TYPE_MPEG4_IN_TS:
demux_close_ts(demuxer); break;
+ case DEMUXER_TYPE_MPEG_PS:
+ demux_close_mpg(demuxer); break;
case DEMUXER_TYPE_REALAUDIO:
demux_close_ra(demuxer); break;
#ifdef USE_LIBAVFORMAT
@@ -616,6 +619,7 @@
extern void demux_open_nuv(demuxer_t *demuxer);
extern int demux_audio_open(demuxer_t* demuxer);
extern int demux_ogg_open(demuxer_t* demuxer);
+extern int demux_mpg_open(demuxer_t* demuxer);
extern int demux_rawaudio_open(demuxer_t* demuxer);
extern int demux_rawvideo_open(demuxer_t* demuxer);
extern int smjpeg_check_file(demuxer_t *demuxer);
@@ -990,7 +994,7 @@
num_h264_pps=0;
num_mp3audio_packets=0;
- if(ds_fill_buffer(demuxer->video)){
+ if(demux_mpg_open(demuxer)){
if(!pes)
mp_msg(MSGT_DEMUXER,MSGL_INFO,MSGTR_Detected_XXX_FileFormat,"MPEG-PES");
else
Index: libmpdemux/demux_mpg.c
===================================================================
RCS file: /cvsroot/mplayer/main/libmpdemux/demux_mpg.c,v
retrieving revision 1.51
diff -u -r1.51 demux_mpg.c
--- libmpdemux/demux_mpg.c 15 Oct 2004 16:11:30 -0000 1.51
+++ libmpdemux/demux_mpg.c 18 Oct 2004 08:19:08 -0000
@@ -17,8 +17,58 @@
//#define MAX_PS_PACKETSIZE 2048
#define MAX_PS_PACKETSIZE (224*1024)
+typedef struct mpg_demuxer {
+ float last_pts;
+ float final_pts;
+ int has_valid_timestamps;
+} mpg_demuxer_t;
+
static int mpeg_pts_error=0;
+/// Open an mpg physical stream
+int demux_mpg_open(demuxer_t* demuxer) {
+ stream_t *s = demuxer->stream;
+ off_t pos = stream_tell(s);
+ off_t end_seq_start = demuxer->movi_end-500000; // 500000 is a wild guess
+ float half_pts = 0.0;
+ mpg_demuxer_t* mpg_d;
+
+ if (!ds_fill_buffer(demuxer->video)) return 0;
+ mpg_d = (mpg_demuxer_t*)calloc(1,sizeof(mpg_demuxer_t));
+ demuxer->priv = mpg_d;
+ mpg_d->final_pts = 0.0;
+ mpg_d->has_valid_timestamps = 1;
+ if (demuxer->seekable && stream_tell(demuxer->stream) < end_seq_start) {
+ stream_seek(s,(pos + end_seq_start / 2));
+ while ((!s->eof) && ds_fill_buffer(demuxer->video) && half_pts == 0.0) {
+ half_pts = mpg_d->last_pts;
+ }
+ stream_seek(s,end_seq_start);
+ while ((!s->eof) && ds_fill_buffer(demuxer->video)) {
+ if (mpg_d->final_pts < mpg_d->last_pts) mpg_d->final_pts = mpg_d->last_pts;
+ }
+ // educated guess about validity of timestamps
+ if (mpg_d->final_pts > 3 * half_pts || mpg_d->final_pts < 1.5 * half_pts) {
+ mpg_d->has_valid_timestamps = 0;
+ }
+ ds_free_packs(demuxer->audio);
+ ds_free_packs(demuxer->video);
+ demuxer->stream->eof=0; // clear eof flag
+ demuxer->video->eof=0;
+ demuxer->audio->eof=0;
+
+ stream_seek(s,pos);
+ ds_fill_buffer(demuxer->video);
+ }
+ return 1;
+}
+
+void demux_close_mpg(demuxer_t* demuxer) {
+ mpg_demuxer_t* mpg_d = demuxer->priv;
+ if (mpg_d) free(mpg_d);
+}
+
+
static unsigned int read_mpeg_timestamp(stream_t *s,int c){
int d,e;
unsigned int pts;
@@ -222,6 +272,7 @@
mp_dbg(MSGT_DEMUX,MSGL_DBG2,"DEMUX_MPG: Read %d data bytes from packet %04X\n",len,id);
// printf("packet start = 0x%X \n",stream_tell(demux->stream)-packet_start_pos);
ds_read_packet(ds,demux->stream,len,pts/90000.0f,demux->filepos,0);
+ if (demux->priv) ((mpg_demuxer_t*)demux->priv)->last_pts = pts/90000.0f;
// if(ds==demux->sub) parse_dvdsub(ds->last->buffer,ds->last->len);
return 1;
}
@@ -357,21 +408,41 @@
demux_stream_t *d_video=demuxer->video;
sh_audio_t *sh_audio=d_audio->sh;
sh_video_t *sh_video=d_video->sh;
+ mpg_demuxer_t *mpg_d=(mpg_demuxer_t*)demuxer->priv;
+ int precision = 1;
+ float oldpts = mpg_d->last_pts;
+ off_t oldpos = demuxer->filepos;
+ float newpts = (flags & 1) ? 0.0 : oldpts;
+ off_t newpos = (flags & 1) ? demuxer->movi_start : oldpos;
//================= seek in MPEG ==========================
- off_t newpos=(flags&1)?demuxer->movi_start:demuxer->filepos;
+ //calculate the pts to seek to
+ if(flags & 2) {
+ if (mpg_d->final_pts > 0.0)
+ newpts += mpg_d->final_pts * rel_seek_secs;
+ else
+ newpts += rel_seek_secs * (demuxer->movi_end - demuxer->movi_start) * oldpts / oldpos;
+ } else
+ newpts += rel_seek_secs;
+ if (newpts < 0) newpts = 0;
if(flags&2){
// float seek 0..1
newpos+=(demuxer->movi_end-demuxer->movi_start)*rel_seek_secs;
} else {
// time seek (secs)
- if(!sh_video || !sh_video->i_bps) // unspecified or VBR
+ if (mpg_d && mpg_d->has_valid_timestamps) {
+ if (mpg_d->final_pts > 0.0)
+ newpos += rel_seek_secs * (demuxer->movi_end - demuxer->movi_start) / mpg_d->final_pts;
+ else if (oldpts > 0.0)
+ newpos += rel_seek_secs * (oldpos - demuxer->movi_start) / oldpts;
+ } else if(!sh_video || !sh_video->i_bps) // unspecified or VBR
newpos+=2324*75*rel_seek_secs; // 174.3 kbyte/sec
else
newpos+=sh_video->i_bps*rel_seek_secs;
}
+ while (1) {
if(newpos<demuxer->movi_start){
if(demuxer->stream->type!=STREAMTYPE_VCD) demuxer->movi_start=0; // for VCD
if(newpos<demuxer->movi_start) newpos=demuxer->movi_start;
@@ -407,6 +478,20 @@
if(i==0x1B3 || i==0x1B8) break; // found it!
if(!i || !skip_video_packet(d_video)) break; // EOF?
}
+ if (!precision || abs(newpts - mpg_d->last_pts) < 0.5 || (mpg_d->last_pts == oldpts)) break;
+ if ((newpos - oldpos) * (mpg_d->last_pts - oldpts) < 0) { // invalid timestamps
+ mpg_d->has_valid_timestamps = 0;
+ break;
+ }
+ precision--;
+ //prepare another seek because we are off by more than 0.5s
+ newpos += (newpts - mpg_d->last_pts) * (newpos - oldpos) / (mpg_d->last_pts - oldpts);
+ ds_free_packs(d_audio);
+ ds_free_packs(d_video);
+ demuxer->stream->eof=0; // clear eof flag
+ d_video->eof=0;
+ d_audio->eof=0;
+ }
}
int demux_mpg_control(demuxer_t *demuxer,int cmd, void *arg){
@@ -414,9 +499,14 @@
demux_stream_t *d_video=demuxer->video;
/* sh_audio_t *sh_audio=d_audio->sh;*/
sh_video_t *sh_video=d_video->sh;
+ mpg_demuxer_t *mpg_d=(mpg_demuxer_t*)demuxer->priv;
switch(cmd) {
case DEMUXER_CTRL_GET_TIME_LENGTH:
+ if (mpg_d && mpg_d->has_valid_timestamps) {
+ *((unsigned long *)arg)=(long)mpg_d->final_pts;
+ return DEMUXER_CTRL_GUESS;
+ }
if(!sh_video || !sh_video->i_bps) // unspecified or VBR
return DEMUXER_CTRL_DONTKNOW;
*((unsigned long *)arg)=(demuxer->movi_end-demuxer->movi_start)/sh_video->i_bps;
@@ -425,6 +515,10 @@
case DEMUXER_CTRL_GET_PERCENT_POS:
if (demuxer->movi_end==demuxer->movi_start)
return DEMUXER_CTRL_DONTKNOW;
+ if (mpg_d && mpg_d->has_valid_timestamps && mpg_d->final_pts > 0.0) {
+ *((int *)arg)=(int)(100 * mpg_d->last_pts / mpg_d->final_pts);
+ return DEMUXER_CTRL_OK;
+ }
*((int *)arg)=(int)((demuxer->filepos-demuxer->movi_start)/((demuxer->movi_end-demuxer->movi_start)/100));
return DEMUXER_CTRL_OK;
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