[LAD] audio recording through pipe using mplayer and sox sometimes has incorrect speed

Stephen Sinclair radarsat1 at gmail.com
Thu Apr 9 18:17:40 UTC 2009

On Thu, Apr 9, 2009 at 8:53 AM, Paul Davis <paul at linuxaudiosystems.com> wrote:
> On Thu, Apr 9, 2009 at 8:24 AM, Arnold Obdeijn <arnold.obdeijn at gmail.com> wrote:
>> Hi all,
>> I am using mplayer, sox and tee to capture streaming internet radio
>> and send it both to an audio recognition program and to a file
>> (recording).
>> This is how I do it:
>> mplayer -playlist {url}  -nocache -af volnorm -msglevel all=1 -nolirc
>> -vc dummy -vo null -ao pcm:file={$fifo1} &
>> sox -S {$fifo1} -c 1 -r 8000 -t wav - resample | tee {$recording} |
>> tee {$fifo2} & ......
>> $fifo1 and $fifo2 are named pipes, $fifo2 is processed by an audio
>> recognition program. The idea is that the audio is converted to low
>> quality wav (8000Hz mono) after which it is fed to the program and
>> simultaneously recorded.
> Not that I want to suggest anything to massively off-topic, but I hope
> you realize that this is a perfect example of the kind of scenario
> that JACK was designed to handle.

On that note, is there a JACK command-line utility that is as easy to
use as "|"?

That would be cool, if a, b, and c were JACK-enabled applications:

$ jack-pipe a : b : c

So much faster than opening up qjackctl and making connections
manually.  Okay, clearly this doesn't handle multichannel very well


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