[mythtv-users] bt878 audio problems

[Matt Vollmar]

David Frey wrote:

> I have this card (from 
> kernel_source/Documentation/video4linux/CARDLIST.bttv)
> card=58 - Askey CPH060/ Phoebe TV Master Only (No FM)
>
> I am having trouble getting any audio when I watch or record TV.  I 
> have the snd_bt87x module installed.  My understanding is that this 
> should allow me to record directly from the tv-tuner card and should 
> not require a patch cable.
>
> Under "capture cards" in mythtv-setup, I have /dev/dsp1 selected as my 
> audio device for recording.  I'm not really sure whether this is 
> correct, or how to verify whether it is correct or not.  What I do 
> know is that /dev/dsp is my soundcard.
>
> alsamixer -c 1 is showing the tv tuner.  "capture" is at 73 and "TV 
> tuner" is selected as the capture device rather than "Mic/Line".
>
> If anyone has any ideas how I can solve this problem or narrow the 
> scope, please tell me.  Also, let me know if there is any other 
> information that would be useful.
>
> Thanks,
> David Frey
>
> Here is my lsmod output:
> $ lsmod
> Module                  Size  Used by
> ide_cd                 42080  0
> cdrom                  40156  1 ide_cd
> sg                     34464  0
> scsi_mod               83584  1 sg
> af_packet              18248  2
> snd_bt87x              14536  0
> 3c59x                  38632  0
> snd_cmipci             33156  2
> snd_pcm_oss            54312  1
> snd_mixer_oss          19904  2 snd_pcm_oss
> snd_pcm                94920  3 snd_bt87x,snd_cmipci,snd_pcm_oss
> snd_page_alloc         11720  2 snd_bt87x,snd_pcm
> snd_opl3_lib           10688  1 snd_cmipci
> snd_timer              25540  2 snd_pcm,snd_opl3_lib
> snd_hwdep               9476  1 snd_opl3_lib
> snd_mpu401_uart         8000  1 snd_cmipci
> snd_rawmidi            24740  1 snd_mpu401_uart
> snd                    52388  10 
> snd_bt87x,snd_cmipci,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_opl3_lib,snd_timer,snd_hwdep,snd_mpu401_uart,snd_rawmidi 
>
> ohci_hcd               17924  0
> usbcore               116260  3 ohci_hcd
> evdev                   9344  0
> sis_agp                 8260  1
> agpgart                34472  1 sis_agp
> tuner                  19920  0
> tvaudio                22348  0
> bttv                  153420  0
> video_buf              22020  1 bttv
> i2c_algo_bit            9800  1 bttv
> v4l2_common             6208  1 bttv
> btcx_risc               4808  1 bttv
> i2c_core               24144  4 tuner,tvaudio,bttv,i2c_algo_bit
> videodev                9728  1 bttv
> soundcore              10016  4 snd,bttv
> unix                   28596  308
>
> Here is my lspci -v for my tv-tuner card:
> 0000:00:0c.0 Multimedia video controller: Brooktree Corporation Bt878 
> Video Capture (rev 02)
>        Subsystem: Askey Computer Corp. MagicTView CPH060 - Video
>        Flags: bus master, medium devsel, latency 32, IRQ 5
>        Memory at fb000000 (32-bit, prefetchable) [size=4K]
>
> 0000:00:0c.1 Multimedia controller: Brooktree Corporation Bt878 Audio 
> Capture (rev 02)
>        Subsystem: Askey Computer Corp. MagicTView CPH060 - Audio
>        Flags: bus master, medium devsel, latency 32, IRQ 5
>        Memory at fa800000 (32-bit, prefetchable) [size=4K]
>
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First, you should check the output of dmesg to see what dsp device comes 
up, if any, since snd_XXX are Alsa drivers.  I use the btaudio module, 
not the snd_bt87x.  Works perfectly for me.  One thing to make sure you 
set is the Max Bit rate for audio capture...it MUST be 32000, at least 
for mine.  If it is set higher, you will get chipmunks running around 
your desktop.  :-P

Matt