I have a couple of Firewire IIDC video cameras that I need to
operate in format 7 mode 0 for full-res 12-bit YUV 411 video
(otherwise they put out a low-res monochrome video stream). And,
they use a Bayer filter array (not sure which one yet).
We don't have a specific API for setting the camera mode, but based
on the requested image size and compression type, you can determine
what mode the driver will use.
What is the modern QT approach to programmatically opening a camera
in a specific format/mode? Is there any QT accommodation for Bayer?
(I understand the standard sequence grabber paradigm, but don't know
how to handle these things.)
Quicktime can support any data format, providing the proper constants
have been defined. After several years of attempting to get Apple to
define four character codes for the IIDC native types, we have
defined our own. They are:
NOTE: Since the IIDC specification cleverly (NOT!) specifies that
cameras producing <16 bits/channel right-justify the data rather than
left-justify as QuickTime does, we may need to add a 2nd
ImageDescription to indicate so that the decode knows how many bits
to shift the data to get full range on decode.
Other vendors are welcome to use these types -- we just got tired of
waiting for Apple to bless constants and needed to ship something.
Note that while kIIDCYUV422Format has the same byte order as '2vuy',
it is not the same format as the ranges are different -- IIDC cameras
return full range data (y=[0..255], u,v=[-127..+127]) while '2vuy' is
"video range" (y=[16..240], u,v=[16..236]), so that conversion from
the IIDC types to '2vuy' is lossy.
The 12-bit Bayer and Grayscale types are the 12-bit types returned by
Optronics cameras.
We provide transcoder components to convert the IIDC types to 'yuv2',
which can be done losslessly and a simple Bayer<->RGB transcoder.
By allowing an application to request Bayer as a compression type,
you can record a movie in raw Bayer to be decoded at playback.
The current Bayer codec is a simple 2x2/3x3, but because the format
is documented, we are hoping that someone will develop a higher
quality Codec using some of the publicly available algorithms.
I'm not sure what type of camera you're using, but if it's not
directly supported, we can add it in relatively short order. (The
problem w/supporting Industrial cameras is that we don't have
infinite budget to buy test cameras -- and, unfortunately, every
camera has it's own weirdnesses)
HTH,
-Steve
--
_________________________________________________________________________
Steve Sisak, CTO email@hidden
IOXperts, Inc. voice: +1 617 876-2572
87 Bristol St #3A fax: +1 617 876-2337
Cambridge, MA 02139 mobile: +1 617 388-6476
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