Messages in this thread | | | Date | Tue, 15 Jul 1997 10:14:06 +0300 (EET DST) | From | Hannu Savolainen <> | Subject | Re: /dev/dsp, and /dev/audio |
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On Sun, 13 Jul 1997, Michael Ballbach wrote:
> I'm trying to determine the format of the sound data returned by > /dev/audio and /dev/dsp. How is this data encoded? I know /dev/audio > returns data as though it were an au, but how is that encoded? Is one byte > frequency, and one byte amplitude? I'm especially interested in /dev/dsp's > format. Thanks for any response. :) Each "sample" returned by /dev/dsp and /dev/audio represent amplitude of the input signal at given moment. When using the default sampling rate of the device (8000 Hz) there is one sample for every 1/8000th of second.
By default each byte returned by /dev/dsp contains amplitude of one sample in 8 bit unsigned format (unsigned char). Value of 0x00 is the minimum and 0xff is the maximum.
/dev/audio returns samples using mu-Law format which is something you don't want to know about.
Btw, programming information for /dev/dsp is available at http://www.4front-tech.com/pguide.
Best regards,
Hannu ----- Hannu Savolainen (hannu@voxware.pp.fi, hannu@4front-tech.com) http://www.4Front-Tech.com/oss.html (Open Sound System (OSS)) http://personal.eunet.fi/pp/voxware (OSS Free/TASD/VoxWare)
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