[MPlayer-dev-eng] MPlayer 1.0rc2 and ALSA 1.0.9, very slow (-nosound help)

[Siarhei Siamashka]

On Thursday 29 May 2008, Jason Zhang (SRC) wrote:
> Hi All,
> I am newbie about MPlayer. Although I have searched the internet carefully,
> I did'nt get the answer. So If my question's answer is very obvious, I
> appologize first.
>
> Environment:
> PXA320,Linux 2.6.14
> Audio driver is alsa 1.0.9 and MPlayer is 1.0rc2. The video device is fbdev
> (800*480, 16bits color depth)
>
> Whatever media file I play, it's very very slow. It takes about 2-3 seconds
> to play one video frame. When I add -nosound flag to mplayer, it looks
> good.
>
> I get some information from mplayer's help:
>
> "If you happen to have a bad audio driver, try the -autosync  option, it
> should sort out your problems."
>
> But that does'nt help me, even set the -autosync to 300.
>
> So I suspect my problem is the classic audio driver issue or not. Could you
> please help?

Most likely your problem is related to slow video decoding and output. If
you try to play video with sound, mplayer tries to synchronize video with the
audio track and if the CPU is not fast enough to decode video in realtime, the
result may look ugly. On the other hand, with audio disabled, you get a very
smooth *slow motion* video playback without a single frame dropped :)

You can use -benchmark option to get some statistics. If you use 
'-nosound -quiet -benchmark' options and mplayer needs for example 3
minutes to play a 2 minutes long video fragment, it is video decoding that
is the bottleneck. While visually you may even not notice that playback is
slower than realtime.

What kind of videos have you tried? You may want to experiment with
transcoding your videos to something like 320x240 resolution.

-- 
Best regards,
Siarhei Siamashka