Openmoko Bug #1614: Mediplayer isn't able to play Ogg/Vorbis files
Russell Sears
sears at cs.berkeley.edu
Wed Jul 16 23:54:41 CEST 2008
I've been looking into this a bit. Some ogg files are playable,
depending on encoding. The problem is that the hardware is too slow to
play ogg files back with the default configuration. It doesn't have a
floating point unit, so things get tricky.
It sounds like pulseaudio shouldn't be using much CPU time at all, at
least according to this thread (which referrs to a different device / os):
http://osdir.com/ml/audio.pulseaudio.general/2007-02/msg00010.html
We probably should figure out what pulseaudio is actually doing, then
look into making it not do that.
I've been trying to figure out where the gst-plugin-vorbisi file's
source code lives for further debugging, but I've been busy and it's
been slow going. I've managed to find the source code for
gst-plugin-vorbis, but that one uses floating point math, and is slower
than the one shipped on the phone.
Beyond fixing the pulseaudio overhead by getting it to stop doing
software mixing / resampling / ???, there are some other things that
could help:
- tremolo, which is an ARM specific version of tremor. Tremor is the
integer math ogg implementation shipped by default
- _LOW_ACCURACY_ mode, which seems to corrupt a few lsbs of the signal,
but saves CPU time.
- Double checking compilation options.
-Rusty
Openmoko Public Trac wrote:
> #1614: Mediplayer isn't able to play Ogg/Vorbis files
> ---------------------+------------------------------------------------------
> Reporter: HdR | Owner: openmoko-devel
> Type: defect | Status: new
> Priority: high | Milestone:
> Component: unknown | Version: 2007.2
> Severity: normal | Keywords: openmoko-mediaplayer
> Blocking: | Blockedby:
> ---------------------+------------------------------------------------------
> As the title says, the openmoko-mediaplayer isn't able to play Ogg/Vorbis
> files.
> The files are added corretly to the play list, but if you press play, the
> mediaplayer only plays a short extract of the track (about the first
> second, maybe).
>
> ogg123 and mplayer are able to play Ogg/vorbis files (with about 50% CPU
> usage), if pulseaudio isn't running.
>
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