Problems Connecting up a Radio Graph

[timh]

Hi,

I'm trying to modify my SS2Recorder plugin to add radio functionality (i.e. the ability to produce an mpg file with just an audio ES) and am having some trouble connecting up the multiplexer filter (CyberLink MPEG Mux).

At the moment, for a normal TV graph the pins would be connected as follows:
1) Render the video output pin on the MPEG-2 Demux to the FileWriter, via the MPEG Multiplexer
2) Render the audio output pin on the MPEG-2 Demux to the MPEG Multiplexer.

This works fine. However, I can't seem to follow a similar approach to connect up a radio graph. The MPEG Multiplexer won't allow an "audio only connection", i.e. the graph builder won't allow me to connect the MPEG-2 Demux audio output pin to the MPEG-Mux audio input pin, unless there is also a video connection.

Looking through the log files for a BDA "radio" graph, I see:

Code:

18:38:45.890    VERBOSE    Setting IID_IMpgMuxer
18:38:45.890    VERBOSE    Initialzing Cyberlink mux for MPEG2 program stream
18:38:45.890    VERBOSE    Setting IID_IMpgMuxer3
18:38:45.890    VERBOSE    Setting IID_IMpgMuxerInfo

So, I'm wondering if this refers to some sort of configuration stage for the muxer which allows it to produce an "audio only" MPEG? If so, this might solve my connection problems. Any suggestions?

Thanks,
Tim

[sub]

Sorry, I cant give you any details about those IMpgMuxer messages - these are covered by a non-disclosure agreement and not publically documented. That said, I'm not using those interfaces to configure an audio-only MPEG. GB-PVR doesnt currently doesnt know anything about DVB radio, so when people are trying to record DVB radio stations, its actually treating it like video.

To do what you're suggesting, I would have though you could either just connect the audio pin to the mux, or possible connect the audio and video pins but have the video pin with no PIDs mapped at the demux end.

It'd only work for recordings, but even better would be connecting the audio pin to a MP3 encoder, and returning the final filename as something.mp3.

[bgowland]

Tim - as sub says, why not record to mp3?

I have an application (originally meant to be a GB-PVR add-in but it never made it) which will record DVB-T radio or just the audio of a TV channel. I simply connect the Audio out pin of the MPEG2 demux via the LAME Encoder filter to the input of a file writer. I don't do anything with the Video out pin on the demux - it doesn't seem to bother it.

Cheers,
Brian

[timh]

GB-PVR doesnt currently doesnt know anything about DVB radio, so when people are trying to record DVB radio stations, its actually treating it like video.

Thanks for the response- just to check, does that mean that in the BDARecorder graph, you are able to have the Mpeg Multiplexer connected and operating without a video input?
Tim

[timh]

Tim - as sub says, why not record to mp3?

Well, yes I could do that (I've managed to produce an mpa simply by missing out the multiplexer). However the attraction of making an mpg is to allow "live" radio (akin to Live TV), also on the MediaMVP.
Cheers,
Tim

[sub]

Thanks for the response- just to check, does that mean that in the BDARecorder graph, you are able to have the Mpeg Multiplexer connected and operating without a video input?
Tim

I've never tested DVB Radio myself, and there is no special logic for it, but yes - I'm guessing it'll just end up with only the audio pin connected.

[timh]

Thanks once again- I've made it work now, by hunting down the pins and explicitly connecting them rather than using the CaptureGraphBuilder2::RenderStream method I was using before.

Got a new problem now though- if I'm recording a radio channel the mpg is created in the Live TV buffer directory and starts to play OK. However, it stops after a minute or so. Looking at the log files, it seems that the file size is being detected as zero (which it's not), presumably this is why playback is told to stop.

Any suggestions how to fix this? I've attached some log files which show the problem occuring- they start off with a normal DVB-T channel (using built in BDA support) then switch to a DVB-S radio channel using the SS2Recorder.

Thanks,
Tim