[linux-dvb] Re: Question regarding PES/Section filters..

[Mike Doyle <michael.doyle@optusnet.com.au>]

On Fri, 25 Oct 2002 01:49, Johannes Stezenbach wrote:
> On Thu, Oct 24, 2002 at 10:34:29AM +1000, Mike Doyle wrote:

<snip>

> Nope. The API documentation only guarantees full sections per read,
> not PES-packets.

<snip>

> For section data the DVB driver always returns full sections, provided
> your buffer is large enough. For PES packets there is no such
> guarantee.

cool...thanks for the correction.  Mucking around with things yesturday (and 
re-reading API), this makes sense.  

Just a further clarification, with a section read, is there any situation ever 
that it will not return a full section (other then running out of buffer)?  

Reason I ask is with some section filters I have going, when I first DMX_START 
them, I get what I am expecting (headers etc), but after stopping and 
restarting them, I sometimes get some junk data. Any ideas why?

I'm spending today working out why.


> Search for the PES start prefix (0x000001 + stream id), then buffer partial
> PES packet data returned from read() until you have a full PES packet.
> Maybe this could be done in the driver, but it isn't now.

don't bother about putting it in the driver...I set up my own parsing buffer 
yestertday, and it was fairly trivial.  My code now passes on full PES 
packets, simular to the pace implementation (IE Sends the head + X bytes, 
then packets of Y bytes until full PES packet is sent...then repeats).

On a side note....very good work on the driver, API.  I like them a lot.  In 
fact, they are heaps better then the PACE stuff I was (and still am) working 
with.

thanks
	Mike


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