On 18/12/17 17:41, Laurent Pinchart wrote:
Hi Tomi,
On Monday, 18 December 2017 14:04:45 EET Tomi Valkeinen wrote:
On 18/12/17 13:50, Laurent Pinchart wrote:
That's an option too. I had a look at the code once to find out how
ImageMagick was performing scaling and gave up with a headache soon
afterwards. We need more formats than what ImageMagick currently supports
(it's mostly focused on image file formats instead of raw image formats),
with all kind of RGB, YUV (and ideally Bayer) formats, and I don't think
extending ImageMagick would be the way to go.
Yep, I can image that ImageMagick can't handle it all. I don't really
have much experience with it. I did find that it has enough tunables to
manage rgbx8888 with different byte orders and the "extra" alpha channel:
convert -depth 8 -size $1x$2 -color-matrix "0 0 1 0 1 0 1 0 0" -alpha
deactivate rgba:$3 png:-
But things like argb1555 or yuv422 might prove to be too difficult for
ImageMagick.
Where's the source for v4l2convert? What does it do?
Sorry, it's v4lconvert, not v4l2convert. The library is part of v4l-utils
(available at git://linuxtv.org/pinchartl/v4l-utils.git) and is found in the
lib/libv4lconvert directory.
The purpose of the library is to convert from lots of weird formats supported
by V4L2 to RGB or YUV. It was initially written to handle vendor-specific
compression formats used by webcams, has been extended to support Bayer
formats and different kind of RGB and YUV formats. The code is simple, I think
it could be a good base.
I wonder how difficult it would be to create a brute-force-no-optimizations
style of a function to which you give the exact bit definition of the
buffer's pixel format, and which gives you RGB888 or YUV444, depending on
the input format (I presume most image encoders would accept RGB888 &
YUV444).
Can you come up with a bit definition format that could describe Bayer or
tiled formats without requiring the definition to be written in an interpreted
language ? :-)
I have only worked with RGB and YUV, so that should be enough for
everybody. ;)
But more seriously, I think kms++ is mainly for display. Do we have any
display devices that support Bayer? And tiled formats sound a bit
special platform specific cases.
That said, if we have a library that just does it all, that's obviously
the best option.
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