[mythtv-users] Recording Radio from STB

[John Pilkington]

Nick Morrott wrote:
> On 08/02/07, Robin Gilks <g8ecj at gilks.org> wrote:
>> Greetings
>>
>> As I understand it, a DVB capture device can recognise a radio (no
>> picture) source and record just the audio.
> 
> It still creates a dummy video stream, which in my experience
> recording from BBC-R4 usually comes out at the same size as the audio
> stream (~50MB for a 30min recording).
> 
>> I'm using a PVR150 to capture from an STB and there are a few radio
>> channels I'm interested in. Is there a way to record these without the
>> hours of still video frame? i.e. just the audio?
> 
> Not that I am aware of for a hardware MPEG2 card. To keep filesizes
> down I suppose you could create a special recording profile with very
> low video bitrate so that total filesizes are as small as possible.
> 
> I haven't tried using the 'recording type' setting and specifying
> 'Audio only' with a PVR card either. I'm not sure how early in the
> encoding process the audio and video streams are separate to allow
> MythTV to access one or the other, or whether the ivtv driver passes
> the already muxed stream encoded with the settings MythTV has passed
> to the driver.
> 
> Nick

I replied to the original post, but my replies have apparently vanished.

With my DVB-T (UK) recording profile set to 'normal' I see the same 
behaviour as Nick; in fact the profile seemed to make no difference 
(atrpms 0.21 'bleeding' build) and I could find no way of selecting 
anything other than the default.  It is usually possible to edit the 
recording but finding the right place to cut is tricky.

I have used avidemux > audio > save to obtain just the audio stream, 
either copied or re-encoded, for stand-alone use, and I would naively 
expect this to work with recordings made from an analog signal created 
by an STB.

I tried transcoding with video resize, but that didn't work. Perhaps I 
set the size too small.

John P