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Diffstat (limited to 'kernel/drv/oss_imux/oss_imux.man')
| -rw-r--r-- | kernel/drv/oss_imux/oss_imux.man | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/kernel/drv/oss_imux/oss_imux.man b/kernel/drv/oss_imux/oss_imux.man new file mode 100644 index 0000000..4d64206 --- /dev/null +++ b/kernel/drv/oss_imux/oss_imux.man @@ -0,0 +1,78 @@ +NAME +oss_imux - Input Muplexer audio driver. + +DESCRIPTION +IMUX is a virtual recording engine that permits up to 8 audio recording +applications to run at the same time. Generally most soundcards permit only a +single recording application to record the input source (via mic, line or CD). +With IMUX, you can use up to 8 recording applications to record the same +source in different sample rates, bits/sample and channels (mono/stereo). +IMUX does all the rate and format conversion in software. The applications +think that they are actually getting data from the physical device. For +instance, if you want to record the input from a CDROM in .wav format at +48Khz/8/Mono and at the same time you want to record the same stream in .mp3 +format in 44.1Khz 16 bit stereo, with IMUX, you can start the wave recording +application on the first IMUX device and start the MP3 encoder on the second +IMUX device and both applications will run simultaneously thinking that they +are getting data from the physical soundcard. + +CONFIGURATION +To add the IMUX driver you first need to ensure that there is a physical +soundcard present and then you can run ossdetect -i to add it. You may want +to select a master device by setting imux_masterdev, but the autodetection +should provide a good default. After OSS restart, imux should be available. + +USAGE +Connect an input source to the soundcard's line-in jack. Using the Mixer app +like ossmix (or any OSS compliant mixer) set the recording source to Line-In +(eg ossmix line.rec ON) Now you can start recording the input in multiple +formats and at different sample rates. The simplest example is: + + ossrecord -s48000 -b16 -c2 -d/dev/oss/oss_imux0/pcmin0 test1.wav & + ossrecord -s8000 -b8 -d/dev/oss/oss_imux0/pcmin0 test2.wav & + +After a few minutes of recording you can stop them by placing the command in +forground mode (type fg %1 or fg %2) and press ^c to stop. + +You now have two wav format files. test1.wav is a 48KHz 16bit stereo file and +test2.wav is a 8Khz 8bit Mono file. + +You can now playback the files as follows: +o ossplay -v test1.wav and it should show you that the file is indeed +48Khz 16bit stereo. + +o ossplay -v test2.wav - you should see that this file is indeed a +8Khz 8bit mono file. + +What you have essentially accomplished is recording a single input stream into +two different formats at the same time. + +You can now extend this analogy to record the input in mp3 format and RealAudio +format simultaneously. + +The IMUX control panel can be displayed by typing ossxmix -d<imux mixer number> +(for e.g. in the above example, IMUX mixer is #2 so we type ossxmix -d2 + +There are record level control sliders for each input channel and it will show +activity when a recording program is active on a particular channel. + + +OPTIONS +o imux_masterdev: Selects which physical device to use as the Master device +for the IMUX driver. +Values: -1: automatically selected by OSS, 1-N: Audio device index of the +master device (as reported by ossinfo -a), Default: -1. + +o imux_rate: Specifies what is the base sampling rate used by the imux driver. +Values: 5000-96000 Default: 48000 + +o imux_devices: Specifies number of Input Multiplexer devices to setup. +Values: 2-48 Default: 5 + + +FILES +CONFIGFILEPATH/oss_imux.conf Device configuration file + +AUTHOR +4Front Technologies + |