[mythtv-users] MythRadio module for DVB radio reception

Dan Sheridan djs52 at postman.org.uk
Wed Apr 14 13:35:59 EDT 2004

On Wed, 2004-04-14 at 15:36, Rob Willett wrote:

> One of my reasons for a DVB card is to get access to BBC 7 for recording old
> comedies.

Same here :-)

Chopped the message about a bit...

> Perhaps we record the audio as MP3's so it can be played in mythMusic 
> easily. It can;t be difficult to switch based one the file format.

> Perhaps inject a video picture of the channel name into the stream
> from the backend and then you don't need to change the front end at 
> all. Keep's things simple.

We can't do both, though. The backend would need to know whether it is
recording to a ringbuffer or a file -- and I don't think it does at the
moment. And I don't like the idea of a 2Mbs stream to include video when
all I want is the 192kbs audio. The frontend part should be very simple,
as most of the complicated bits are there to handle synchronisation.

At least for my old analogue radio code, it would be necessary to
transcode to get an mp3 out. I suspect that the most straightforward
implementation for DVB would involve a transport stream containing just
an MP3, which could be easily extracted. 

> > o Add a "Live Radio" option which sets up an audio-only ringbuffer,
> >   maybe some visualisations or something, and asks the backend to tune
> >   to a radio channel. It will only select other radio channels when you
> >   switch.
> Does the backend tune to a radio station or just another data stream that
> happens not to have video?

I was thinking of those as being the same thing. (I can't imagine being
able to tune to a channel with no video that isn't a radio station)

> > o Change the next and previous channel functions to stick to radio or TV
> >   channels as requested by the frontend
> Why not leave them as they are, Freeview set's don't distingusih (or mine
> doesn't). Why treat things differently, it only creates work.

Because (without the video injection hack you mentioned) the frontend
cannot handle a stream without video -- it locks up waiting for the next
frame. It would only be possible if a message could be sent notifying
the frontend that there was no video in the stream. I haven't looked at
whether this can be done. 

Thinking about this some more, there must be an "okay" reply when the
channel change is done which could include the "sorry, no video"
message, causing us to disable the sync code. Maybe we don't need to
distinguish radio from TV, then. 

> > The important thing, of course, is what Isaac thinks of this
> > arrangement...

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