diff options
Diffstat (limited to 'Documentation/sound/alsa/Bt87x.txt')
| -rw-r--r-- | Documentation/sound/alsa/Bt87x.txt | 78 |
1 files changed, 0 insertions, 78 deletions
diff --git a/Documentation/sound/alsa/Bt87x.txt b/Documentation/sound/alsa/Bt87x.txt deleted file mode 100644 index f158cde8b065..000000000000 --- a/Documentation/sound/alsa/Bt87x.txt +++ /dev/null @@ -1,78 +0,0 @@ -Intro -===== - -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. snd-bt87x 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... - -Some cards do not bother to connect anything to the audio input pins of -the chip, and some other cards use the audio function to transport MPEG -video data, so it's quite possible that audio recording may not work -with your card. - - -Driver Status -============= - -The driver is now stable. However, it doesn't know about many TV cards, -and it refuses to load for cards it doesn't know. - -If the driver complains ("Unknown TV card found, the audio driver will -not load"), you can specify the load_all=1 option to force the driver to -try to use the audio capture function of your card. If the frequency of -recorded data is not right, try to specify the digital_rate option with -other values than the default 32000 (often it's 44100 or 64000). - -If you have an unknown card, please mail the ID and board name to -<alsa-devel@alsa-project.org>, regardless of whether audio capture works -or not, so that future versions of this driver know about your card. - - -Audio modes -=========== - -The chip knows two different modes (digital/analog). snd-bt87x -registers two PCM devices, one for each mode. They cannot be used at -the same time. - - -Digital audio mode -================== - -The first device (hw:X,0) gives you 16 bit stereo sound. The sample -rate depends on the external source which feeds the Bt87x with digital -sound via I2S interface. - - -Analog audio mode (A/D) -======================= - -The second device (hw:X,1) gives you 8 or 16 bit mono sound. Supported -sample rates are between 119466 and 448000 Hz (yes, these numbers are -that high). If you've set the CONFIG_SND_BT87X_OVERCLOCK option, the -maximum sample rate is 1792000 Hz, but audio data becomes unusable -beyond 896000 Hz on my card. - -The chip has three analog inputs. Consequently you'll get a mixer -device to control these. - - -Have fun, - - Clemens - - -Written by Clemens Ladisch <clemens@ladisch.de> -big parts copied from btaudio.txt by Gerd Knorr <kraxel@bytesex.org> |