Color problem with MPX-885 card (cx23885)

Color problem with MPX-885 card (cx23885)

[Neuer User]

Hello

First of all, I don't know, if this is the right mailing list. I haven't
found any other. The video4linux list seems to be abandoned.

I am testing a Commell MPX-885 mini-pcie card, which is based on a
cx23885 chip. There is "initial" support in the linux kernel for this card:

http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=commit;h=2cb9ccd4612907c0a30de9be1c694672e0cd8933

My system is based on Ubuntu 12.04LTS amd64 with kernel 3.2.0.32.

The driver in general works. There are a couple of problems, however,
which to my mind are probably easy to fix for someone understanding the
driver:

1.) MINOR PROBLEM: The card is not auto-recognized. The module needs to be
loaded with the option "card=32" to get it recognized.
2.) MINOR PROBLEM: With PAL camera, there is a black left border of
about 20-30 pixel. No border on the right side.
3.) MAJOR PROBLEM: The image is mainly black & white only with some
green and red information. There are vertical light green and red stripes

I have attached a captured image demonstrating the color problem (and
also the border) to a bug report here:
https://bugzilla.kernel.org/show_bug.cgi?id=50411

I would really like to get this card fully working. Is there anybody
here who can help me or direct me to a place where someone can help me.

Thanks a lot

Michael

Re: Color problem with MPX-885 card (cx23885)

[Devin Heitmueller]

On Tue, Nov 13, 2012 at 9:10 AM, Neuer User <auslands-kv@gmx.de> wrote:
> Hello
>
> First of all, I don't know, if this is the right mailing list. I haven't
> found any other. The video4linux list seems to be abandoned.
>
> I am testing a Commell MPX-885 mini-pcie card, which is based on a
> cx23885 chip. There is "initial" support in the linux kernel for this card:
>
> http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=commit;h=2cb9ccd4612907c0a30de9be1c694672e0cd8933
>
> My system is based on Ubuntu 12.04LTS amd64 with kernel 3.2.0.32.

You should start by installing the current media_build tree.  There
were a bunch of cx23885 fixes done back in June, which won't be in
12.04.  I believe this issue may already be fixed.

Cheers,

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com

Re: Color problem with MPX-885 card (cx23885)

[Neuer User]

Hello David

Thanks for taking the time to help.

I had looked through the linux-media GIT tree for any commits that have
"cx23885" in the description. The last ones I found were from mid 2011.

That was probably why I did not try any newer kernels. Stupid me. Should
have tried anyway.

I can confirm that the biggest problem, the color problem, is fixed at
least with kernel 3.5.7 (maybe earlier).

The minor ones (card not autodetected, and black border on the left
side) can probably be dealt with, e.g. in postprocessing. Or is there a
chance to fix these in the driver?

Michael

Am 13.11.2012 16:02, schrieb Devin Heitmueller:
> You should start by installing the current media_build tree.  There
> were a bunch of cx23885 fixes done back in June, which won't be in
> 12.04.  I believe this issue may already be fixed.
> 
> Cheers,
> 
> Devin
> 

Re: Color problem with MPX-885 card (cx23885)

[Devin Heitmueller]

On Tue, Nov 13, 2012 at 11:39 AM, Neuer User <auslands-kv@gmx.de> wrote:
> I had looked through the linux-media GIT tree for any commits that have
> "cx23885" in the description. The last ones I found were from mid 2011.

Yeah, the changes were actually made to the cx25840 driver, which is
used/shared by the cx23885.

> I can confirm that the biggest problem, the color problem, is fixed at
> least with kernel 3.5.7 (maybe earlier).

Ok, good.

> The minor ones (card not autodetected, and black border on the left
> side) can probably be dealt with, e.g. in postprocessing. Or is there a
> chance to fix these in the driver?

They can almost certainly be fixed in the driver (the black border is
a result of incorrect HSYNC configuration for PAL standards).  The
bigger issue though is finding someone willing to do the work.  If
this is for a commercial application, you may wish to reach out to
Steven Toth.  He did the original MPX support as a consulting project.

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com

Re: Color problem with MPX-885 card (cx23885)

[Neuer User]

Am 13.11.2012 18:07, schrieb Devin Heitmueller:
> On Tue, Nov 13, 2012 at 11:39 AM, Neuer User <auslands-kv@gmx.de> wrote:
>> The minor ones (card not autodetected, and black border on the left
>> side) can probably be dealt with, e.g. in postprocessing. Or is there a
>> chance to fix these in the driver?
> 
> They can almost certainly be fixed in the driver (the black border is
> a result of incorrect HSYNC configuration for PAL standards).  The
> bigger issue though is finding someone willing to do the work.  If
> this is for a commercial application, you may wish to reach out to
> Steven Toth.  He did the original MPX support as a consulting project.
> 
> Devin
> 

Hi Devin

Thanks for the help.

The HSYNC problem is bigger than I thought. I compared the captured
image with an image from another (USB) video digitizer and it is obvious
that the image has lost about 10-20% on the right side and on the bottom.

Can probably be easily fixed. But it is no commercial project, so I need
to do it myself, I guess. I hope there are some settings in the driver.
Any idea where I need to look? (Is it the cx23885 driver at all or even
the cx25840?)

Michael

Re: Color problem with MPX-885 card (cx23885)

[Devin Heitmueller]

On Tue, Nov 13, 2012 at 1:02 PM, Neuer User <auslands-kv@gmx.de> wrote:
> The HSYNC problem is bigger than I thought. I compared the captured
> image with an image from another (USB) video digitizer and it is obvious
> that the image has lost about 10-20% on the right side and on the bottom.
>
> Can probably be easily fixed. But it is no commercial project, so I need
> to do it myself, I guess. I hope there are some settings in the driver.
> Any idea where I need to look? (Is it the cx23885 driver at all or even
> the cx25840?)

Almost certainly just changes needed for the cx25840 driver.  These
are all basic issues with the video decoder core.  Google around - the
cx25840 datasheet is readily available.  You have to watch out though
because there are some subtle differences that you won't be able to
detect if it's a cx23887 or cx23888 as opposed to the cx23885.

Regarding the cropped image, what capture resolution are you using?
Perhaps the scaler isn't working and you're setting the capture to
something like "640x480" (which would effectively crop out lines
640-720 on the horizontal and lines 480-576 on the vertical).

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com

Re: Color problem with MPX-885 card (cx23885)

[Neuer User]

Am 13.11.2012 19:54, schrieb Devin Heitmueller:
> Almost certainly just changes needed for the cx25840 driver.  These
> are all basic issues with the video decoder core.  Google around - the
> cx25840 datasheet is readily available.  You have to watch out though
> because there are some subtle differences that you won't be able to
> detect if it's a cx23887 or cx23888 as opposed to the cx23885.

Well, I will try to have a look at the sources, but probably, I won't be
able to patch it correctly, if the changes necessara are more than
absolutely basic and obvious...

I once compiled the tw68 driver for another card. And here the borders
were also not correct. In this driver it was very easy to find the
settings to change.
> 
> Regarding the cropped image, what capture resolution are you using?
> Perhaps the scaler isn't working and you're setting the capture to
> something like "640x480" (which would effectively crop out lines
> 640-720 on the horizontal and lines 480-576 on the vertical).
> 
> Devin
> 

Thanks, you probably hinted me into the right direction. I use mplayer
to play the video stream and mplayer does indeed recognize a 640x480
video stream.

I am not using any crop settings for these tests. But maybe it is
possible to tell mplayer that the stream is 720x576 instead of the
640x480 it believes. That is, if the stream coming from the driver is
really not 640x480.

Re: Color problem with MPX-885 card (cx23885)

[Devin Heitmueller]

On Tue, Nov 13, 2012 at 2:03 PM, Neuer User <auslands-kv@gmx.de> wrote:
> Thanks, you probably hinted me into the right direction. I use mplayer
> to play the video stream and mplayer does indeed recognize a 640x480
> video stream.
>
> I am not using any crop settings for these tests. But maybe it is
> possible to tell mplayer that the stream is 720x576 instead of the
> 640x480 it believes. That is, if the stream coming from the driver is
> really not 640x480.

Just to be clear, I wasn't intending to suggest that you were using
any of the actual V4L2 cropping features.  I'm just saying that if the
video scaler were broken, it's possible that the frames are
*effectively* being cropped at 640x480.

But yeah, you should definitely try capturing at 720x576 in mplayer.
You can specific command line arguments to mplayer to set the width
and height.

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com

Re: Color problem with MPX-885 card (cx23885)

[Neuer User]

Am 13.11.2012 20:12, schrieb Devin Heitmueller:
> Just to be clear, I wasn't intending to suggest that you were using
> any of the actual V4L2 cropping features.  I'm just saying that if the
> video scaler were broken, it's possible that the frames are
> *effectively* being cropped at 640x480.

Absolutely, you found the problem. Thanks a lot. Indeed as soon as I
define a resolution (even the 640x480) I get the full picture. Only if
NO resolution is specified, I get 640x480 as a croped version.

Funny bug. For me I can live with the current solution. I can define the
resolution with mplayer and crop out the black left border. (Hopefully
QTMultimedia can do that also...)

Again, you have been very helpful. Thank you very very much.

Michael

> 
> But yeah, you should definitely try capturing at 720x576 in mplayer.
> You can specific command line arguments to mplayer to set the width
> and height.
> 
> Devin
>