[MPlayer-dev-eng] [PATCH] Timestamp-based mpg seeking
Michael Behrisch
behrisch at informatik.hu-berlin.de
Fri Oct 15 14:24:56 CEST 2004
On Wed, Oct 13, 2004 at 02:22:55PM +0200, Aurelien Jacobs wrote:
> On Tue, 12 Oct 2004 13:06:17 +0200
> Michael Behrisch <behrisch at informatik.hu-berlin.de> wrote:
>
> >
> > This patch will reduce the number of "-ss does not work"
> > and "dvd length is wrong" messages by more than 80% ;-)!
> > It enables indeed precise seeking and retrieves the total
> > time of the movie almost always correctly (and it can also
> > walk your dog).
>
> :-)
>
> I've tested it with some mpeg files and DVDs. It works very well !
> I think this is a real improvement, and something like this should
> be commited.
>
> About the code:
>
> +/// Open an mpg physical stream
> +int demux_mpg_open(demuxer_t* demuxer) {
> + off_t pos = stream_tell(demuxer->stream);
> + if (!ds_fill_buffer(demuxer->video)) return 0;
> + mpg_demuxer_t* mpg_d = (mpg_demuxer_t*)calloc(1,size...
>
> This is generally a bad idea to declare variables in the middle
> of a function. gcc-2.95 don't accept this.
There are a lot of positions in the code where this happens
(maybe only at beginnings of blocks?) Nevertheless fixed.
All cosmetics fixed as well.
Michael
-------------- next part --------------
diff -u libmpdemux.old/demuxer.c libmpdemux/demuxer.c
--- libmpdemux.old/demuxer.c 2004-10-12 12:58:51.000000000 +0200
+++ libmpdemux/demuxer.c 2004-10-14 22:18:01.061965160 +0200
@@ -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
diff -u libmpdemux.old/demux_mpg.c libmpdemux/demux_mpg.c
--- libmpdemux.old/demux_mpg.c 2004-09-24 12:41:20.000000000 +0200
+++ libmpdemux/demux_mpg.c 2004-10-14 22:44:38.743080712 +0200
@@ -17,8 +17,57 @@
//#define MAX_PS_PACKETSIZE 2048
#define MAX_PS_PACKETSIZE (224*1024)
+typedef struct mpg_demuxer {
+ float last_pts;
+ float final_pts;
+} 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);
+ 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;
+ // 500000 is a wild guess
+ off_t end_seq_start = demuxer->movi_end-500000;
+ 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->final_pts = 0.0;
+ }
+ 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 +271,7 @@
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;
}
@@ -357,8 +407,23 @@
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;
//================= seek in MPEG ==========================
+ //calculate the pts to seek to
+ float newpts = flags & 1 ? 0.0 : oldpts;
+ 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;
+
off_t newpos=(flags&1)?demuxer->movi_start:demuxer->filepos;
if(flags&2){
@@ -366,12 +431,17 @@
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->final_pts > 0.0)
+ newpos += rel_seek_secs * (demuxer->movi_end - demuxer->movi_start) / mpg_d->final_pts;
+ else if (mpg_d && mpg_d->last_pts > 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 +477,16 @@
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;
+ 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 +494,14 @@
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->final_pts > 0.0) {
+ *((unsigned long *)arg)=(long)mpg_d->final_pts;
+ return DEMUXER_CTRL_GUESS;
+ }
if(!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 +510,10 @@
case DEMUXER_CTRL_GET_PERCENT_POS:
if (demuxer->movi_end==demuxer->movi_start)
return DEMUXER_CTRL_DONTKNOW;
+ if (mpg_d && 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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