[linux-dvb] Re: Linux DVB API 4 Q's

[Rob.McConnell@Zarlink.Com]

Hi,

> On Mon, Sep 22, 2003 at 09:27:07PM +0200, Ralph Metzler wrote:
> > Rob.McConnell@Zarlink.Com writes:
> >  >
> >  > A. If we want to route a TS/PS/PES off a DVD or HDD through a PID
filter,
> >  > then I guess we would have to setup the source type of the filter to
be
> >  > "DVB_DMX_SOURCE_FRONTEND" with the correct "frontend_num". The same
goes
> >  > for an input from an external C/A modules or LVDS, etc.  Is this the
> >  > intention?  Does the term "front-end" really make sense?
> >
> >
> > See the discussion about general input devices. I do not care if they
> > are all called input or frontend but they should be treated equally.
> > Normally the demuxes can choose one of the inputs of the whole demux
> > block as source and you cannot bypass this. So, data should be
> > written to a frontend/input device and not to a demux. If you can
> > bypass this, then one could always make writing directly into
> > the demux device possible just for this hardware.
> > Or how do you handle the case if two demuxes are supposed to process
> > the same data from memory?

> I'm just reading
> http://linuxtv.org/mailinglists/linux-dvb/2003/03-2003/msg00116.html

> I'm currently inclined to drop enum dvb_dmx_source_type and just
> use the frontend file descriptor in DVB_DMX_SET_SOURCE.

This would make sense for each logical demux device having a separate input
source.  All PID filters (and section filters) attached to this logical
demux device would have the same input source.  For playback from HDD, you
could create another logical demux device that has it's input from memory.
Then you do a write() on that logical demux device's fd (the one that you
1st opened in RW mode).

> For stream playback or external inputs we could add other
> input devices. I.e. we would never write data to the demux
> device, only to connected "playback" devices.

I prefer to keep the ability to write to the logical demux device directly,
but have no problems with other input devices being created.  I guess
another TODO would be to cater for DMAs from say memory to the demux device
for playback of data from a DVD/HDD.

> Currently I think it's best to keep the frontend devices
> as-is, and just add new non-generic input device types.

I agree.

Rob : )







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