[mythtv] Re: [mythtv-commits] Ticket #926: Radio channels for DVB-T

David Matthews dm at prolingua.co.uk
Wed Jan 4 17:23:58 UTC 2006

> In the states, for digital TV we have MusicMatch audio stations, I've noticed 
> at least for me they get broadcast in the clear, but the video channel for 
> them is not linked like normal channels by the program ID, and when you find 
> the video ID the video is more like a slide show where an image is sent out 
> then nothing for some seconds then the next video image. Would something like 
> this allow me to tune the audio PID and not worry about the video so I could 
> at least listen to the station?

Possibly.  It simply looks at the filters that are added and uses the 
dummy video if there isn't a video PID in the PMT.  What it will do with 
the MusicMatch stations will depend on what's in the PMT they're 

> This works GREAT for me! Just one (seemingly stupid question), what's
> necessary in order to change the resolution of the blank video frames? I'd
> either prefer a 16/9 aspect or an NTSC (640x480).

I simply copied what was currently used in the dummydtvrecorder except 
that there is extra code in tv_rec.cpp to select different resolutions 
and frame rate for ATSC.  I haven't done that so far because I wasn't 
sure whether the code was useful outside the UK.  If it is then I'll do 

There are instructions in dummydtvrecorder to create your own stream. 
You can then replace themes/default/dummy768x576p50.00.ts with whatever 
you want.  The only constraint is to retain the 50 fps.

Actually, it might be better to change the code to 25 fps for PAL but 
that would have meant creating a new MPEG TS stream and I wanted to 
minimise the changes until I'd had some feedback.


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