[linux-audio-dev] I need help! I can't handle the problem about full-duplex (playback & record) programming

leo zhu leozhuca at yahoo.com
Fri Dec 13 18:52:01 UTC 2002


Hi, guys,

I am working on a project in which I need to implement
palyback and recording on the same sound card and in
the same time. 

I open the soundcard with RDWR mode and used 'select'
to wait for sound data on card and read it. After
that, I receive audio data from socket and write this
data into buffer on card. for now. I tested it and i
found if just one way, ie. just read or write, it
works fine, the quality of sound is fine. but if two
way, ie. play&record, the sound is horrible and the
weird is that I always get better sound quality from
playback that what i got from recording. (I heard the
audio from two ends). by the way, I used
SNDCTL_DSP_TRIGGER to syncronyse them.

can this method implement full-duplex functions ? if
not, what should I do? thanks in advance

leo

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