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diff --git a/Documentation/sound/oss/btaudio b/Documentation/sound/oss/btaudio deleted file mode 100644 index effdb9a3f898..000000000000 --- a/Documentation/sound/oss/btaudio +++ /dev/null @@ -1,92 +0,0 @@ - -Intro -===== - -people start bugging me about this with questions, looks like I -should write up some documentation for this beast. That way I -don't have to answer that much mails I hope. Yes, I'm lazy... - - -You might have noticed that the bt878 grabber cards have actually -_two_ PCI functions: - -$ lspci -[ ... ] -00:0a.0 Multimedia video controller: Brooktree Corporation Bt878 (rev 02) -00:0a.1 Multimedia controller: Brooktree Corporation Bt878 (rev 02) -[ ... ] - -The first does video, it is backward compatible to the bt848. The second -does audio. btaudio is a driver for the second function. It's a sound -driver which can be used for recording sound (and _only_ recording, no -playback). As most TV cards come with a short cable which can be plugged -into your sound card's line-in you probably don't need this driver if all -you want to do is just watching TV... - - -Driver Status -============= - -Still somewhat experimental. The driver should work stable, i.e. it -should'nt crash your box. It might not work as expected, have bugs, -not being fully OSS API compliant, ... - -Latest versions are available from http://bytesex.org/bttv/, the -driver is in the bttv tarball. Kernel patches might be available too, -have a look at http://bytesex.org/bttv/listing.html. - -The chip knows two different modes. btaudio registers two dsp -devices, one for each mode. They can not be used at the same time. - - -Digital audio mode -================== - -The chip gives you 16 bit stereo sound. The sample rate depends on -the external source which feeds the bt878 with digital sound via I2S -interface. There is a insmod option (rate) to tell the driver which -sample rate the hardware uses (32000 is the default). - -One possible source for digital sound is the msp34xx audio processor -chip which provides digital sound via I2S with 32 kHz sample rate. My -Hauppauge board works this way. - -The Osprey-200 reportly gives you digital sound with 44100 Hz sample -rate. It is also possible that you get no sound at all. - - -analog mode (A/D) -================= - -You can tell the driver to use this mode with the insmod option "analog=1". -The chip has three analog inputs. Consequently you'll get a mixer device -to control these. - -The analog mode supports mono only. Both 8 + 16 bit. Both are _signed_ -int, which is uncommon for the 8 bit case. Sample rate range is 119 kHz -to 448 kHz. Yes, the number of digits is correct. The driver supports -downsampling by powers of two, so you can ask for more usual sample rates -like 44 kHz too. - -With my Hauppauge I get noisy sound on the second input (mapped to line2 -by the mixer device). Others get a useable signal on line1. - - -some examples -============= - -* read audio data from btaudio (dsp2), send to es1730 (dsp,dsp1): - $ sox -w -r 32000 -t ossdsp /dev/dsp2 -t ossdsp /dev/dsp - -* read audio data from btaudio, send to esound daemon (which might be - running on another host): - $ sox -c 2 -w -r 32000 -t ossdsp /dev/dsp2 -t sw - | esdcat -r 32000 - $ sox -c 1 -w -r 32000 -t ossdsp /dev/dsp2 -t sw - | esdcat -m -r 32000 - - -Have fun, - - Gerd - --- -Gerd Knorr <kraxel@bytesex.org> |