[mythtv] [PATCH] generic libavformat seek support (5)

[John P Poet]

On 5/13/05, Mark Spieth <mark at dclabs.com.au> wrote:
>  
> with johns file I have found another big bug in libavformat. 
> the packet structures are not initialised before av_read_packet. 
> in some instances, this structure is not filled by the underlying format,
> notably mpegts in this case. 
> This causes segfaults. 
> I have found now I that it seems in general more stable and snappy, finding
> and exiting at the end of file quite nicely. It should cause less packet
> errors due to this invalid data in previously used AVPacket header data (pts
> etc). 
> Ive made the fix generic just in case other formats do some nasty things and
> have left mpegts.c alone. overhead is minimal. 
> It now works for johns file, though I cant play the hd properly due to
> something in my video setup. the savage stuff just doesnt like the higher
> res and renders badly and slowly. but thats my problem. ;-) 
> please test with other formats to see what else crops up. but its looking
> more stable now. 
> exact seeks is still forced on for the moment. this is in
> AvformatDecoder::DoFastForward if you want to play. 
> will next check on mpeg seeking keyframes which doesnt happen at the moment.
> avi part seeks keyframes ok for me. 
> ignore the guff for the moment. Ill remove it as soon as Im happy. 
> also for transcoding purposes, myths db indexing is also filled in in case a
> mythcommflag --video is desired. Not sure if this is desirable or not but
> thought some people might be relying on it. 
> cheers 
> mark 


Still no joy with the mpeg2 files I tried importing from my old
ReplayTV, but everything else I have tried has worked very nicely.  I
have not tried any mov files, but I have tried some xvid and some
mpeg4 files.

When I skip forward or backward, the video smears badly for a couple
of seconds, but then settles down and looks fine.  I don't skip around
much in these files, so it is no big deal, just wanted to report it
since mplayer does not have that problem.

Don't worry too much about those ReplayTV mpeg2 files, like I said,
they are probably not well formed.  I can watch them if I have myth
transcode them into a mpeg4 file.

As it stands right now, it is very usable and useful.  I have not been
able to get it to crash.  I hope this gets included into the Myth CVS.

Thank you!

John