2017-06-04 17:05:50

by Alexandre-Xavier L-L

[permalink] [raw]
Subject: Weird green patterns on video

Hello,

Someone sent me a picture of a device that he tried to add support for
in V4L2. The device causes a kind of diagonal pattern made of green
lines on his image. I wonder what could be causing this. Has anyone
seen this before?

The device is a the first ever model of Ion Video 2 PC that uses a TM6010 chip.

What he got: https://sebbro.nl/ION_Video2PC-TM6010_BOARD_GENERIC.png

Expected result (captured from another device):
https://sebbro.nl/VCR-reference.png

The support for the device was added by adding
{ USB_DEVICE(0x15e4, 0x0140), .driver_info = TM6010_BOARD_GENERIC },
to tm6000-cards.c.

Thanks in advance for any clues.
Alexandre-Xavier


2017-06-04 17:50:15

by Ilia Mirkin

[permalink] [raw]
Subject: Re: Weird green patterns on video

On Sun, Jun 4, 2017 at 1:05 PM, Alexandre-Xavier L-L <[email protected]> wrote:
> Hello,
>
> Someone sent me a picture of a device that he tried to add support for
> in V4L2. The device causes a kind of diagonal pattern made of green
> lines on his image. I wonder what could be causing this. Has anyone
> seen this before?
>
> The device is a the first ever model of Ion Video 2 PC that uses a TM6010 chip.
>
> What he got: https://sebbro.nl/ION_Video2PC-TM6010_BOARD_GENERIC.png
>
> Expected result (captured from another device):
> https://sebbro.nl/VCR-reference.png
>
> The support for the device was added by adding
> { USB_DEVICE(0x15e4, 0x0140), .driver_info = TM6010_BOARD_GENERIC },
> to tm6000-cards.c.
>
> Thanks in advance for any clues.
> Alexandre-Xavier

YUV zero = RGB greenish, as you see there. From the looks of it, the
pitch on the buffer is wrong, and you're showing the parts of the
buffer that are left zeroed as if they were part of the visible
region. (Pitch = how many bytes between lines, which is not
necessarily the visible width of the buffer, as it can be rounded up
to various values for various reasons.)

Hope this helps,

-ilia

2017-06-04 20:08:43

by Alexandre-Xavier L-L

[permalink] [raw]
Subject: Re: Weird green patterns on video

Thanks, but I lack the technical knowledge of how the driver works, so
I don't know how I could fix this issue. How do I adjust the pitch on
the buffer?

The owner of the device is willing to ship it for free to anyone that
would add support for the device. No need to send it back to the owner
once fixed. Send me a private reply if you, or anyone else, are
interested.

The device is from Europe, I don't know if that would cause any
problem when trying to use it with devices from North America.

Have a nice day,
Alexandre-Xavier

On Sun, Jun 4, 2017 at 1:50 PM, Ilia Mirkin <[email protected]> wrote:
> On Sun, Jun 4, 2017 at 1:05 PM, Alexandre-Xavier L-L <[email protected]> wrote:
>> Hello,
>>
>> Someone sent me a picture of a device that he tried to add support for
>> in V4L2. The device causes a kind of diagonal pattern made of green
>> lines on his image. I wonder what could be causing this. Has anyone
>> seen this before?
>>
>> The device is a the first ever model of Ion Video 2 PC that uses a TM6010 chip.
>>
>> What he got: https://sebbro.nl/ION_Video2PC-TM6010_BOARD_GENERIC.png
>>
>> Expected result (captured from another device):
>> https://sebbro.nl/VCR-reference.png
>>
>> The support for the device was added by adding
>> { USB_DEVICE(0x15e4, 0x0140), .driver_info = TM6010_BOARD_GENERIC },
>> to tm6000-cards.c.
>>
>> Thanks in advance for any clues.
>> Alexandre-Xavier
>
> YUV zero = RGB greenish, as you see there. From the looks of it, the
> pitch on the buffer is wrong, and you're showing the parts of the
> buffer that are left zeroed as if they were part of the visible
> region. (Pitch = how many bytes between lines, which is not
> necessarily the visible width of the buffer, as it can be rounded up
> to various values for various reasons.)
>
> Hope this helps,
>
> -ilia