[vdr] Re: Re : VDR files to vob

[Malcolm Caldwell <malcolm.caldwell@ntu.edu.au>]

I could well be wrong here - it has been a while since I looked at mpeg
parsers but...  in my recollection:

What people are saying here is correct: a PS is basically PES with some
additional headers.

One of the things that can be in these headers is the mpeg start code.  
This is a sequence of bytes (0x000001BA unless I am mistaken) that says
basically "The program stream starts here".

Many mpeg players (all the ones whose code I have read) do something
like this at the very beginning:

while (nextbytes != MPEG_START_CODE) {
	skipbytes;
}
And then start parsing stream.

In fact, the players I have looked at, after they find the start code
skip all the other header information and only process the PES packets.

I would guess that not having the start code is what causes many players
to have troubles.  (Unless vdr already puts in start codes - I have only
had a quick look at the code)

It should be fairly easy to add the PS headers stuff to the VDR files
and it would probably help things a lot.

On Mon, 2002-07-15 at 06:14, Andreas Schultz wrote:
> Hi,
> 
> On Sunday 14 July 2002 21:12, Klaus Schmidinger wrote:
> 
> [...]
> 
> > I guess what I'd first like to see is somebody who can explain
> > *EXACTLY* what PES and PS is, and what the difference between these
> 
> I guess i have outed myself already earlier, but let's see if i have learned 
> something.
> 
> Everything is really explained in ISO/IEC-13818-1.
> 
> Section 2.4.3.6 describes PES packets. VDR already deals with those.
> 
> Section 2.5.3.3 describes PS packets. PS streams can contain a number of 
> different packet types. One of those being PES packets, others are mostly 
> only relevant in DVB streams.
> For us the only relevant PES packet type is 0xBA. It contains a SCR (system 
> clock reference), the stream mux rate and the PES packet itself.
> 
> So PS streams really are PES stream with an small additional header that 
> contains no really usefull information. The only possible info in there is 
> the SCR, which can be used to sync the decoder to the encoder. But the DVB 
> card is not using this.
> 
> Andreas
> -- 
> Andreas Schultz <aschultz@cs.uni-magdeburg.de>
> Student of computer science
> 
> "In accordance with plans for Linux OS world domination
>       infiltration of governments is vital (:-))."
-- 
Malcolm Caldwell <malcolm.caldwell@ntu.edu.au>
Northern Territory University