[libdvbpsi-devel] TS files that has PCR hickups

[Jean-Paul Saman]

1) can you sent a link with a faulty file
2) report which version of vlc you use

Morgan Tørvolt wrote:
> Hi
> 
> As I did not get any response from the vlc-devel list, I am trying
> this mailing list instead. Hopefully someone can help me out here so
> that this problem can be fixed. I would love to help out myself, but a
> hint on where to begin would be much appreciated.
> Below is a copy of my original message go vlc-devel:
> 
> 
> Hi.
> 
>  I was told to use this mailing list on the IRC channel, please advice
>  if this is the wrong place for it.
> 
>  I have been testing the VLC output transportstream files for use in a
>  streaming server. I use DVDs for testing, and do nothing but mux them
>  to a ts file, keeping all elementary pids. This works reasonably well
>  with live555 streaming.
> 
>  I have found some issues though, and they all seem to revolve around
>  the PCR in the TS being faulty at some point. Whatever DVD I use, I
>  get random occurences of the a PCR being signalled as earlier than the
>  previous, usually resulting in the following PCRs having very long
>  durations between to compensate and get back on track.
> 
>  I have made a program that gets both PCR in hex, shows a floating
>  point representation of it, and shows the first 20 bytes of the TS
>  packets, as well as calculate the duration per packet using current
>  and previous PCR values.
> 
>  It has become obvious that it happens on random spots (some seen 4-6
>  seconds apart, others 300-400 seconds apart), but often at about the
>  same length of time into the movie on different movies.
> 
>  I have found no good explaination for this. At first I thougth it
>  could have something to do with faulty PTS/DTS timestamps, so I
>  printed the DTS as well, but they seem pretty consistent.
> 
>  Using the DTS as timing for the playout actually helped a lot, giving
>  lot less trouble in the other end, but seemingly the client seems to
>  have some issues still, flickering mostly. I am wondering if some
>  timing information inside the MPEG stream is also affected, but I have
>  not gotten that far yet. I was hoping someone here could explain the
>  problems so that I did not have to =)
> 
>  I have pasted a printout from my program, showing the actual issue here:
>  http://paste.videolan.org/3381
> 
>  As you can see, I get the correct information from the TS packet, and
>  that the actual data in the TS packet is not consistent. I could have
>  some errors in my floating point conversion, but the issue is apparent
>  in the original data as well, so I am quite confident that I have not.
> 
>  I print "ERROR HERE" if there is a negative or an unreasonably high
>  packet duration period.
> 
>  Thanks for any help on resolving this.
> 
> 
>  Regards
> 
> Morgan Tørvolt
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> 

Gtz
Jean-Paul Saman.