Re: [jokosher-devel] Pipeline clock problems

[Laszlo Pandy <laszlok2 gmail com>]

John Green wrote:
> 0:00:00.272167000 26312 0x804f070 WARN                  alsa
> gstalsasrc.c:428:set_hwparams:<alsasrc0> error: Rate doesn't match
> (requested 44100Hz, get 0Hz)

I'm wondering if there is a way to catch this specific error and 
blacklist the specific audio rate. Bilboed, is that possible?


> This may be an issue for 'real' cards rather than vmware setups so we
> probably need to check out card capabilities somehow. I'm not a gst
> expert but I'm assuming the rate reported in the getcaps line in the
> log is a range and 44100 is within that range but it still doesn't
> work. 

That's exactly right. We hide all of the rates in the preferences dialog 
that your sound card has told us it won't accept. If 44100 is still an 
option, your sound card is a liar.

> Will it be better to build the pipeline with gst functions
> rather than gst.parse_launch? I don't know if that would give us the
> ability to test if the pipeline will work before we start play.

Its the same thing. gst.parse_launch just makes building the pipeline 
less code quicker in certain circumstances. Its not like the command 
line tool where it will start playing automatically. You still have to do:
pipeline = gst.parse_launch(...)
pipeline.set_state(gst.STATE_PLAYING)

We could also try pausing the pipeline first to see if it breaks, but by 
that time we are already locking the input on the sound card. And we 
shouldn't do that until the user asks us to.

Laszlo