I've been going through the specs for zr36067 and zr36060 thinking about
following: Using dc10+ as a mjpeg compressor for uncompressed video data
residing somewhere in system memory.
It seems that ZR36067 supports "fast still image compression and
decompression" and has a dedicated interface for the host to write
uncompressed data which is then placed on the video bus for zr36067 to
process. How does the output compare to mjpeg?(are there any "motion"
specific headers missing, etc.) Could you create an mjpeg movie file with
this method?
Reason I'm after this is because the video decoder of dc10+ just plain sucks.
I have in my system also a voodoo3 3500tv with vpx322x decoder that is just
so much better. Unfortunately 3dfx in it's great wisdom didn't include bus
mastering capabilities to this card so it is not quite as useful as a video
capture device as say a dc10+.
I've been trying to create decent looking vcd-compliant files with the dc10+
but downscaling from 640/608 or upscaling from 320/304 to 352 just doesn't
quite cut it. Vpx322x could do decimation to a specific amount of pixels and
the end result would probably be so much nicer.
So here's what I'm planning. Vpx322x captures a frame to the v3500tv
framebuffer. An interrupt is generated upon completion. This frame is then
transferred directly from the framebuffer to the zr36067 using still image
compression facilities. Rest of it goes exactly like the current dc10+
drivers work: Compressed data is transferred to main memory buffers using dma.
I was kind of hoping that zr36067 could use dma to transfer the data to be
compressed too but it seems that this is not possible.
I was trying to find a mechanism from the v4l-drivers of zoran based cards to
use the still image (de)compression facilities but besides few #defines there
doesn't seem to be any interface. It probably wouldn't be too hard to add.
Any comments? Is this reasonable to accomplish. Sure would raise the value of
my v3500tv and dc10+.
Oh, I did write quite a bit of the drivers for v3500tv so creating the hooks
in those would not be a problem. It is the zoran-drivers that I'm a little
less familiar with(had the card for about 1.5days now).
- Juha
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