[linux-dvb] Re: V4 API proposal

["Haber, Thomas" <THaber@tee.toshiba.de>]

Hi Florian,

Florian Schirmer wrote:
> C) The hardware demux has to export a logical demuxX device 
> for _each_ hw
> input channel it supports (e.g. if the hw supports 2 frontend 
> and 1 memory
> based input it will export demux0,demux1,demux2). It is up to 
> the user to
> map these logical devices to hw inputs (via DMX_SET_SOURCE)

The number of demux devices should depend on 
how many input streams can be handled in parallel.

> 4. Multiple filters per FD
> 
> Multiple filters per FD will be supported through
> DXM_ADD_FILTER/DMX_DEL_FILTER ioctls. We did not decide yet wether we
> 
> A) allow just a single pid per call
> B) allow multiple pids per call
> C) require multiple pids to be set in a single call
> 

I agree that this is a much better approach than using the dvr.
But please consider that when doing this we will get a functiuonality that is not demultiplexing.
Instead its somehow TS filtering and here we may need additional functionality that does not
fit into the demux.
The partial output stream can consist one or more programs. We also need the filter some tables to 
get the stream information when doing playback. To have a consistent TS stream we need to 
change the PAT and reinsert it into the stream.


> 5. Output control (TAP, decoder, HDD)
> 
> Yet another item which needs some pro/cons discussions.
> 

So far I don't know what you think about my proposal, please let me know.

> 6. Playback of non TS data (PES, AVPES, ...)
> 
> You are only allowed to write TS data to the demux. All other 
> data has to be
> written to the a/v decoder (if availible). We probably need 
> to design a
> second api/filter layer to support all different kinds of a/v data. I
> propose creating a new device (e.g. avdecoderX) and combine 
> the existing
> audioX/videoX with the new filter api. Needs some discussion too. Low
> priority. Maybe V5 item?

Concerning PS and multiple PES, it also needs to be demuxed. We also need to set filters based on the streamids, we have timing information similar to STC, and we also have data that corresponds to tables.  
When this is in the same device the interface will get differnt meanings. If not we will get a TsDemux and a PsDemux.

Regards,

thomas 


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