[streaming] Re: Trying to emulate VLC streaming in a test equipment, but failing

[Chhaya, Harshal]

Jean-Paul,

Thanks a lot for your response and explanation.

> The test equipment should update the version numbers of the 
> PAT and PMT if they change. And set the discontinuity bit 
> in the TS header. 
> Basically your test equipment isn't following MPEG2-TS 
> specifications.

My test equipment has no idea that it is playing a video
stream. It is a network tester and just plays back the
traffic bytes that I load into it. In this case, the
traffic bytes happen to be a video stream that was 
captured at the network interface of the PC running
VLC in the streaming mode.

Since my test equipment is not video aware, how do I set the
'discontinuity' bit in the TS header? Are there other tools
that let me do this? I can even do this manually - update
the right byte, once I know which one - in the byte stream
before loading it on the equipment. I have to do this only for 
the first TS packet, right? 

Since it is looping the same 10-sec video clip forever,
I guess I don't have need to change the PAT and PMT, do I?


> > BTW, I found the 'use sequential numbers instead of 
> > timestamps' option in vlc 0.8.6 and enabled it but it didn't 
> > make any difference.

I realised later that this obviously wouldn't make any 
difference because it has nothing to do with video playback. 
I was frantically looking for some setting enable this one 
without realising that it is not for video playback but for
'snapshot' mode.


> > FWIW, mplayer can play the stream even from the test equipment
> > but the video quality gets progressively worse. It also can't
> > play the audio which is in mp3 format.
> 
> VLC uses the specifications and MPLayer doesn't. So when a 
> file can be played with mplayer it doesn't mean the stream is 
> according to specification. Only that mplayer is less stringent.

I agree completely. But in this particular case, my goal was to
demo my network functionality and I had to use whatever worked.

If I know more about how to fix my video byte stream, I can make
it more spec compliant and use vlc to play it back.

Thanks again for your explanation.

- Harshal

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