[linux-dvb] Re: Fw: DVB audio/video decoder API

[Dennis Noordsij <dennis.noordsij@wiral.com>]

> The entire recording and "Transfer Mode" mechanisms of VDR are based on the
> assumption that the driver can deliver TS packets, since that's the most
> basic form of data (AFAIK that's the way it is broadcast), and it is the
> easiest way to distribute the data to various receivers. This is what made,
> for instance, "overlapping recordings" possible in VDR. I also don't see
> how one would be able to record more than one programme (or one programme
> with several audio PIDs) if the driver delivers PES. As far as I understand
> things this is only possible if it delivers TS (but please correct me if
> I'm wrong here).

Unless this is technically not possible (someone speak up please! :-), think 
of running multiple instances of pesdump, i.e.
pesdump video_pid_1 > file_1 &
pesdump audio_pid_2 > file_2 &
pesdump audio_pid_3 > file_3 &

ASSUMING (this is what nobody has answered for me yet :)) the av_pes streams 
contain enough information to resynchronize them later, OR, to be at least 
able to synchronize them into one file with sync info while the app is 
reading them.

ASSUMING every single PID of a transponder can be arbitrarily grabbed this 
way, limited of course by the PCI bus and AV7111 performance/memory

ASSUMING the driver does not need to do any special processing to be able to 
provide these streams to the app other than routing it through.

ASSUMING the app can turn this around and give an av_pes stream back to the 
driver to go to the card's decoder.

ASSUMING that you have now eliminated both the TS muxing in the driver and the 
TS demuxing in the app, and the main CPU's job is reduced to routing streams 
of data around, while the driver complexity is reduced.

THEN this becomes an attractive solution.

If a program really needs the TS, or likewise if the app really needs av_pes 
streams on a nova card, the dvb library can do the conversions.

BUT we need people to clear up the assumptions :-))

Cheers,
Dennis

PS - This does not take into account the processing and handling required of 
scrambled content. I guess special hoops apply for that.


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