On Thu, 16 Apr 2009, Thomas Kaiser wrote:
Hello Theodore
My answers/comments inline .....
Mine, too. I will also cut out some currently non-interesting parts, in
the interest of saving space.
On 04/16/2009 01:59 AM, Theodore Kilgore wrote:
Thomas,
A few questions in the text below.
On Thu, 5 Mar 2009, Thomas Kaiser wrote:
Hello Theodore
kilgota@xxxxxxxxxxxxxxxxxxxxxx wrote:
From usb snoop.
FF FF 00 FF 96 64 xx 00 xx xx xx xx xx xx 00 00
and
In Linux the header looks like this:
FF FF 00 FF 96 64 xx 00 xx xx xx xx xx xx F0 00
1. xx: don't know but value is changing between 0x00 to 0x07
as I said, this signifies the image format, qua compression algorithm in
use, or if 00 then no compression.
On the PAC207, the compression can be controlled with a register called
"Compression Balance size". So, I guess, depending on the value set in the
register this value in the header will show what compression level is set.
One of my questions:
Just how does it work to set the "Compression Balance size"? Is this some
kind of special command sequence? Are we able to set this to whatever we
want?
It looks like. One can set a value from 0x0 to 0xff in the "Compression
Balance size" register (reg 0x4a).
In the pac207 Linux driver, this register is set to 0xff to turn off the
compression. While we use compression 0x88 is set (I think the same value
like in Windoz). Hans did play with this register and found out that the
compression changes with different values.
I wonder how this relates to the mr97310a. There is no such register
present, that I can see.
Hans, may you explain a bit more what you found out?
(Yes, please.)
2. xx: this is the actual pixel clock
So there is a control setting for this?
Yes, in the PAC207, register 2. (12 MHz divided by the value set).
Again, I wonder how this might translate for the mr97310a ...
The following is pretty much the same, it seems.
3. xx: this is changing according light conditions from 0x03 (dark) to
0xfc (bright) (center)
4. xx: this is changing according light conditions from 0x03 (dark) to
0xfc (bright) (edge)
5. xx: set value "Digital Gain of Red"
6. xx: set value "Digital Gain of Green"
7. xx: set value "Digital Gain of Blue"
Varying some old questions: Precisely what is meant by the value of
"Digital Gain for XX" where XX is one of Red, Green, or Blue? On what scale
is this measured? Is is some kind of standardized scale? Or is it something
which is camera-specific? Also what is does "set" mean in this context?
This last in view of the fact that this is data which the camera provides
for our presumed information, not something which we are sending to the
camera?
When I recall correctly, I just saw that this fields in the header have the
same value which I set in the "digital gain of Red/Green/Blue" registers.
Therefor, I called it "set" value. But I don't remember if a change of these
registers had any impact on the picture.
Hmmm. My experience is that these settings depend purely on the frame, and
whether the camera is pointed at something bright or something dark, that
kind of thing. Thus my idea was to try to use the information, somehow, in
a constructive way. It never occurred to me, actually, that it is possible
to "set" these things by issuing commands to a camera. But what do I know?
The range for these registers is from 0x0 to 0xff but as I don't know what
they do, I don't know any more :-(
Yes, that I can understand.
Theodore Kilgore
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