[pvrusb2] saa7115 1-0021: Video signal: bad

Wed Feb 20 23:31:21 CST 2008

On Wed, 20 Feb 2008, dan wrote:

> I recently installed mepis 7. I have a wintv-pvr-usb2 (29032 rev d158) 
> box. I use it for simple tv viewing on xp (works great). The box is 
> connected to cable tv.
> 
> I cannot get the box working with xawtv, kdetv, tvtime or kmplayer. I 
> receive the subject line in dmesg and the players report no video. wow!!

When you receive that message, is it the one you get right when you plug 
in the device, or are you seeing it when you attempt to stream video?

The dmesg output in your message is clearly the result of plugging in 
the device (which is as expected).  Those status messages you see in the 
output are just that - status at that point in time.  At the time when 
the device is plugged in, it isn't streaming anything so of course the 
status output from the various chip drivers are all going to indicate no 
video, no signal, etc.  So if you are seeing "saa7115 1-0021: Video 
signal:  bad" only when you plug in the device, then it's actually 
correct in that case and you can ignore it.  If however this is 
happening when you try to stream video (e.g. run mplayer, run xawtv, 
etc), then that's a real clue.

Another important bit: tvtime is *never* going to work.  That 
application requires real-time raw video frames from the hardware, not 
self-timed compressed video like the pvrusb2-driven devices will emit.  
So that application is not ever going to work.  However mplayer and 
xawtv should work (when set up correctly).  I suspect kdetv won't work 
because (I think) it is looking for a DVB interface and that's not (yet) 
possible with the V4L-based pvrusb2 driver.  I assume kmplayer is a 
wrapper around mplayer so whatever is true with mplayer should be true 
with kmplayer.

There is a page in the pvrusb2 documentation that discusses what apps 
work and what you may or may not have to do to get them to work.  Since 
you mentioned tvtime and since that page states that tvtime won't ever 
work, I have to assume that you haven't seen that page yet.  Here's a 
direct link:

http://www.isely.net/pvrusb2/usage.html#V4L

In particular there is information present on that page which describes 
how to get mplayer (e.g. can't run it in v4l mode) and xawtv (e.g. has 
to be built with the correct libraries) to work.  It's entirely possible 
that you're already doing the right things, but please go back and look 
at that page.  Confirm that you're setting things up correctly, then if 
you're still having problems we can dig deeper.  For example, a useful 
experiment is to separate the RF tuner out of this and to try to stream 
video from a DVD player, VCR, or a camcorder - if you can get that to 
work then we'll know that whatever problems are left have to do with the 
RF tuner.  Conversely, if that doesn't work then we know that there are 
problem(s) not involving the RF tuner.

   [...]

> 
> Apparently the kernel has all the required driver modules and firmware 
> pre installed ???? or do I need to install? ... If so how?  I downloaded 
> all from your site but don't know which or what to use...

Whether or not the kernel has everything depends on the kernel version.  
But anything 2.6.18 or later should have everything you need.  You can 
still download and install a pvrusb2 tarball if you want; that will give 
you later code.  This page of the documentation:

http://www.isely.net/pvrusb2/setup.html

talks about what you need to do depending on kernel version and how you 
are installing the driver.  If you look at this page:

http://www.isely.net/pvrusb2/pvrusb2.html

and scroll down towards the end of the "Overview" section you'll see a 
bit titled "Driver software versions: standalone vs in-V4L vs 
in-kernel", and it's there where you can find out more about which 
driver version you might want to use.  Generally these days just using 
the in-kernel driver is the easiest and that driver is pretty stable.  
But you still always have the option to install a later driver on top of 
the kernel, if perhaps you need support for a newer device (not the case 
for you) or if you want to play with some newer features (which the most 
recent changes are really all internal anyway).

I know that the pvrusb2 driver documentation is lengthy and somewhat, 
uh, "deep".  But you have to understand (and I have since learned) that 
it is a really tough thing to write documentation where it's both easy 
to find what you're looking for while still at the same time covering 
all the various corner cases and wierd situations that people have come 
across.  When I started documenting this it was all a single HTML page.  
I kept on expanding it as I encountered more things that people would 
get wrong or that might be problematic.  Eventually that one page just 
became too hard to follow - the more common information tended to be 
scattered about, hidden by the corner cases.  What's there now is the 
result of a big reorganization I had done a while back.  I made one high 
level page with the most important points, but then pushed the details 
down to other pages, each referenced appropriately from the top page.  
The idea is that someone could quickly go through the top page and then 
link to the specific places where he/she might require more details or 
answers for his/her specific situation.  It's still not perfect, but the 
information *is* there.

> 
> Also, xawtv output run:
> :~$ xawtv
> This is xawtv-3.95.dfsg.1, running on Linux/i686 (2.6.22-1-mepis-smp)

Hmm, well here's your first problem: The version of xawtv you are using 
doesn't support mpeg decoding.  It's too old.  The usage page I had 
mentioned earlier warns about this.  Again, here's the link:

http://www.isely.net/pvrusb2/usage.html#V4L

Right there in the second sentence under the "xawtv" category it states:

"Note that anything before version 4 will definitely not work with this 
since earlier versions did not support mpeg2 decoding."

> /dev/video0 [v4l2]: no overlay support
> v4l-conf had some trouble, trying to continue anyway
> Warning: Cannot convert string 
> "-*-ledfixed-medium-r-*--39-*-*-*-c-*-*-*" to type FontStruct
> libGL warning: 3D driver claims to not support visual 0x4b
> v4l2: read: rc=294912/size=442368
> 
> 
> Thanks, and please correct my protocol if needed...... (I have posted to 
> mepis board with no reply and spent hours on google and reading your info )
> dan

First bit of advice: Read the usage page I mentioned earlier.  Then 
apply what you find, and tell me if things are better after that point.

  -Mike

-- 

Mike Isely
isely @ pobox (dot) com
PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8