Re: [RFC] v4l2 support for thermopile devices

From: Matt Ranostay
Date: Fri Nov 04 2016 - 01:13:56 EST


On Thu, Nov 3, 2016 at 8:11 AM, Luca Barbato <lu_zero@xxxxxxxxxx> wrote:
> On 03/11/2016 14:21, Attila Kinali wrote:
>> On Wed, 2 Nov 2016 23:10:41 -0700
>> Matt Ranostay <matt@xxxxxxxxxxxxxxxxxxx> wrote:
>>
>>>
>>> So does anyone know of any software that is using V4L2_PIX_FMT_Y12
>>> currently? Want to test my driver but seems there isn't anything that
>>> uses that format (ffmpeg, mplayer, etc).
>>>
>>> Raw data seems correct but would like to visualize it :). Suspect I'll
>>> need to write a test case application though
>>
>> I was pretty sure that MPlayer supports 12bit greyscale, but I cannot
>> find where it was handled. You can of course pass it to the MPlayer
>> internas as 8bit greyscale, which would be IMGFMT_Y8 or just pass
>> it on as 16bit which would be IMGFMT_Y16_LE (LE = little endian).
>>
>> You can find the internal #defines of the image formats in
>> libmpcodecs/img_format.h and can use https://www.fourcc.org/yuv.php
>> to decode their meaning.
>>
>> The equivalent for libav would be libavutil/pixfmt.h
>>
>> Luca Barbato tells me that adding Y12 support to libav would be easy.
>>
>> Attila Kinali
>>
>
> So easy that is [done][1], it still needs to be tested/reviewed/polished
> though.

Cool. Although needs to be processed since it is signed value, and
because it it is really just 0C based readings with 0.25C steps.. But
will look into that when I get a chance.

Anyway did hack in basic support so v4l2grab so I could test the
sensor, and seems to work well but needs some colorized processing to
be useful of course.

Soldering iron about 1 meter from sensor -> http://imgur.com/a/8totG


>
> [1]:https://github.com/lu-zero/libav/commits/gray12
>
> lu