[MPlayer-users] Re: audio filters drain the cpu

[Fabio Papa]

Fredrik Eriksson wrote:
> Tobias Diedrich wrote:
> 
>> Fredrik Eriksson wrote:
>>  
>>
>>> playing a audiofile like
>>>
>>> mplayer music.mp3
>>>
>>> works just fine, without any notable cpu usage. However, trying to 
>>> use a audiofilter, like
>>>
>>> mplayer -af sub music.mp3
>>>
>>> or
>>>
>>> mplayer -af surround music.mp3
>>>   
>>
>>
>> I can reproduce that on my SB Live.
>> Can you try the attached patch and see if it makes the problem go away 
>> for you?
>>
>> It seems like snd_pcm_status_get_avail returns something not a
>> multiple of chunk_size, but snd_pcm_writei only writes multiples of
>> chunk_size.  The while-loop in ao_alsa then retries with the remainder
>> and the next call to snd_pcm_writei is busy-waiting.
>>  
>>
> That patch worked somewhat, now most of the time the cpu usage is down 
> to a more reasonable level (about 1-2%), but at times it still goes up 
> to 99-100% for no apparent reason, and then goes down again.
> 
Just for the sake of discussion, have you determined wheter you're using
OSS or ALSA as output device? I've seen the exact same behaviour as you
two, but the problem went completely away using ALSA instead of OSS...

Fabio.