[linux-dvb] RE : linux-dvb and Dektec [was: DVB API update]

Felix Domke tmbinc at elitedvb.net
Thu Oct 4 15:55:32 CEST 2007


Andrea Venturi wrote:
> - the PowerPc SoC inside some DVB SET TOP BOX as Dreambox and the 
> DGStation CubeCafe (Vulcan and Pallas)
> they do have actually a linux kernel running on the powerpc core but the 
> decoding API are a bit "home made" and binary too (maybe thing are 
> changing..)

The PowerPC-based Dreamboxes still use the old DVB-API (its initial 
drivers predate the change to the new API, and never followed it), 
whereas the newer Dreamboxes (DM7025 and the hopefully upcoming DM8000) 
are using the current API. (There was also an effort to build new 
Pallas/Vulcan APIv3 drivers as GPL, but this had to be pulled for legal 
reasons. Those drivers were never complete, though.)

All are using binary-only driver modules for different reasons, but all 
conform to the available userspace API as much as possible. Sometimes a 
few additions were required (see also my discussion about 
VIDEO_GET_{PTS,STC} etc.), but they use (for example) the 
/dev/dvb/adapter0/video0-API.

Another implementation is the dbox2, which uses open-source drivers. And 
don't forget the old full-featured cards.

However sometimes the API is not completely clear (like the order: Do 
you first have to do a VIDEO_PLAY, then start the demux? Things like 
that are sometimes even hardware-dependent and are likely to differ from 
implementation to implementation. Sometimes you need to be tricky for 
proper syncing, and trickmodes are a completely gray area...) But for 
just playing video, the API should be ok. Don't forget that all hardware 
MPEG decoders are beasts, and likely to be tricky in operation. The API 
should hide the ugly details, but that's not always possible.

Felix



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