01 Dec 2009 |
Posted by Devin Heitmueller | 2 Comments.
Probably one of the most popular questions I see new users ask about tvtime is along the lines of the following:
It looks like tvtime is working (showing me video), but for some reason I am not hearing any audio. What is wrong with my tuner?
Unfortunately, in the vast majority of cases, there is nothing wrong with the tuner. The problem is that tvtime was originally designed to be used with older tuner cards that have a dedicated audio output cable, which you are expected to connect to speakers. Most newer tuner products deliver their audio via an ALSA device, for which tvtime has no mechanism to route the audio to your soundcard.
I started to work on this over the last couple of days. I’ve got some code written which basically works, although progress was significantly slowed by an apparent bug in the Intel HDA audio driver. For once it’s not my driver causing the problem, so I can happily point out that despite what is probably caused by a misuse of the ALSA API on my part, *nothing* I can ever do in userland should ever cause a kernel panic. Heh.
I’m also trying to nail down some lipsync issues. Reducing the latency to 30ms so that the audio gets delivered within one frame of the video is more of a challenge than it would seem.
Anyway, I am hoping to get something into the Mercurial tree in the next few days if all goes well. Until the media controller framework is introduced, we still don’t know *which* ALSA device is associated with the tuner, so we will have to ask the user the first time. But this is still *much* better than expecting the user to run sox or arecord/aplay in a separate terminal window (which always seemed like a rather ridiculous workaround).