[linux-dvb] Re: mplayer playback through dvb takes 100% cpu time

[Michael Hunold <hunold@convergence.de>]

Hello Soeren,

I'm currently investigating this problem.

I have inserted some debugging output into the dvb driver, but it did 
not reveal any problems. So I think it's an sync issue of mplayer. (see 
below)

On 03.01.2004 22:33, Soeren Sonnenburg schrieb:
> I noticed a weirdness with mplayer and -vo mpegpes playback. If I don't
> also use -ao mpegpes the CPU load goes up to 100% instead of like 10%,
> i.e. both 
> mplayer -ao mpegpes -vo mpegpes <file>
> and 
> mplayer -nosound -vo mpegpes <file> 
> both take like 10% CPU but, 
> mplayer -ao null -vo mpegpes <file>
> or
> mplayer -ao alsa9 -vo mpegpes <file>
>
> eat up all CPU there is but plays (of course gives frame drops)
I think one important thing is "-nosound".

While "-ao null" is a valid "sound device" which "consumes" the sound 
with a defined rate (just like -ao alsa9), "-nosound" simply disables 
sound output and uses some constants to skip audio inside mplayer.c.

Perhaps there is a problem that "-vo mpegpes" needs the raw PES data, 
but "-ao null" or "-ao alsa9" need the decoded PCM audio, and so 
decoding and timing the output are severly messed up.

> Soeren.
Perhaps some of the mplayer developers can comment on this. In the 
meanwhile, I'm going to profile mplayer and the kernel in order to see 
where the 50% in-kernel time is actually spent.

Any help is appreciated...

CU
Michael.


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