bttv channels and subchannels (multi channel bttv cards)

[Steven.Z]

Hi,

How do you list all available channels on all /dev/video* devices?

I've purchased a PV-149 8-Port (120FPS) card and after installing it in my Ubutnu 9.04 setup I did some investigation. I noticed that even though the card supports 8-ports, only four devices were loaded for the card.

I learned out that all 8-ports are available becuase each /dev/video* device support 2-channels. But I figured this out just by playing around with ZoneMinder for sometime. How can I use Linux to list all channels available on a /dev/video* device?

Also when using xawtv/zmu, I must list a device, since my card supports multiple channels on one device how can I supply this argument to utility? Or does it always assume to use the first channel (i.e., 0)?

steven@viao:/usr/share/zoneminder$ uname -a
Linux viao 2.6.28-14-generic #47-Ubuntu SMP Sat Jul 25 00:28:35 UTC 2009 i686 GNU/Linux

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steven@viao:/usr/share/zoneminder$ dmesg | grep "bttv.*found"
[   12.993741] bttv: Bt8xx card found (0).
[   13.024100] bttv: Bt8xx card found (1).
[   13.056066] bttv: Bt8xx card found (2).
[   13.088083] bttv: Bt8xx card found (3).

Are /dev/vbi* the second channels for /dev/video* ?

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steven@viao:/dev$ ls -al | grep video
crw-------   1 root   video    10, 175 2009-08-09 18:26 agpgart
crw-rw----+  1 root   video    81,   1 2009-08-09 18:26 vbi0
crw-rw----+  1 root   video    81,   3 2009-08-09 18:26 vbi1
crw-rw----+  1 root   video    81,   5 2009-08-09 18:26 vbi2
crw-rw----+  1 root   video    81,   7 2009-08-09 18:26 vbi3
crw-rw----+  1 root   video    81,   0 2009-08-09 19:11 video0
crw-rw----+  1 root   video    81,   2 2009-08-09 18:55 video1
crw-rw----+  1 root   video    81,   4 2009-08-09 18:26 video2
crw-rw----+  1 root   video    81,   6 2009-08-09 18:26 video3

Notice how xawtv shows me four devices, but what about the channels?

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steven@viao:~$ sudo xawtv -hwscan
This is xawtv-3.95.dfsg.1, running on Linux/i686 (2.6.28-14-generic)
looking for available devices
port 56-56
    type : Xvideo, image scaler
    name : SIS 300/315/330 series Video Overlay

port 57-72
    type : Xvideo, image scaler
    name : SIS 315/330 series Video Blitter

/dev/video0: OK                         [ -device /dev/video0 ]
    type : v4l2
    name : BT878 video (ProVideo PV150)
    flags: overlay capture  

/dev/video1: OK                         [ -device /dev/video1 ]
    type : v4l2
    name : BT878 video (ProVideo PV150)
    flags: overlay capture  

/dev/video2: OK                         [ -device /dev/video2 ]
    type : v4l2
    name : BT878 video (ProVideo PV150)
    flags: overlay capture  

/dev/video3: OK                         [ -device /dev/video3 ]
    type : v4l2
    name : BT878 video (ProVideo PV150)
    flags: overlay capture

[Steven.Z]

Does my question make any sense?

[curtishall]

https://secure.bluecherry.net/support/i ... ticleid=11

That should help.

[chenko]

Ubuntu always detected my bttv cards as video0 *and* vbi0... they are the same device.

As the link says, you have 4 devices (one per chip on the board), each with 2 channels (0 and 1).

This means you have 30fps per "device" to share. So the 120fps is just 4x 30fps chips... you won't get any higher than 30fps per channel obviously.

When adding a new Monitor in Zoneminder, look in the top right hand corner, there is a "Probe" option which should nicely list all of your available devices/channels


I think dmesg should show it detecting the channels for you too.