Re: [VCDImager Bugs/Devel] code to parse mpeg-2 down to frame level.

[Mike Bernson]

Herbert Valerio Riedel wrote:
> 
> a big thank you! :)
> 
> I've learned a lot (again) by this code of yours. I've merged it in, while
> rewriting vcd_mpeg.c and related modules...
> 
> take a look at cvs, I'd like to know if I really have to fill that
> search.dat with i-frame-points (if so, I'll make it quick'n'dirty by
> estimating the scanpoints... only if this does not work I'll make the
> right way -- well... and for version 1.0 I'll do it the right way anyway
> :)
> 
> I'm estimating the playtime by looking at the timecode at the beginning
> and the end of the mpeg1/2 stream, and then taking the difference of it...
> 
> ...this should work most of the time for genuine mpeg streams, right?
> 
> btw, I've been looking at the dumped mpeg frame output... why does the
> timecode offset to last GOP timestamp sometimes decrement from one frame
> to the next one? :-/
>
There is a problem with time timecodes. You call vcd_mpeg_get_timecode
which zero the packet and then parse the video. When it get to gop
parse code the frame rate is set to zero. This causes it drop the
last part of the timecode. In the stream I have last gop has
a fame with the timecode 2 and the gop has timecode 00:00:29:28 which
means that the stream 00:00:30:1 long but you report it as 00:00:29:0
long.

At a min you need to fix the code so that it does not drop the frame
part of the timecodes. You also need  to see what frames are in the last
gop. 


Time does display as the stream plays but it can not fast forward or
fast backward or time search.

I think we need to build search file. To make thing work here.