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@lists.sf.net>, 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>
Download Driver Pack
After your driver has been downloaded, follow these simple steps to install it.
Expand the archive file (if the download file is in zip or rar format).
If the expanded file has an .exe extension, double click it and follow the installation instructions.
Otherwise, open Device Manager by right-clicking the Start menu and selecting Device Manager.
Find the device and model you want to update in the device list.
Double-click on it to open the Properties dialog box.
From the Properties dialog box, select the Driver tab.
Click the Update Driver button, then follow the instructions.
Very important: You must reboot your system to ensure that any driver updates have taken effect.
For more help, visit our Driver Support section for step-by-step videos on how to install drivers for every file type.