Re: RFC on proposed patches to mr97310a.c for gspca and v4l

[Thomas Kaiser <thomas@kaiser-linux.li>]

Thomas Kaiser wrote:
> Hello Theodore
> 
> kilgota@banach.math.auburn.edu wrote:
>> Also, after the byte indicator for the compression algorithm there are 
>> some more bytes, and these almost definitely contain information which 
>> could be valuable while doing image processing on the output. If they 
>> are already kept and passed out of the module over to libv4lconvert, 
>> then it would be very easy to do something with those bytes if it is 
>> ever figured out precisely what they mean. But if it is not done now 
>> it would have to be done then and would cause even more trouble.
> 
> I sent it already in private mail to you. Here is the observation I made 
> for the PAC207 SOF some years ago:
> 
>  From usb snoop.
> FF FF 00 FF 96 64 xx 00 xx xx xx xx xx xx 00 00
> 1. xx: looks like random value
> 2. xx: changed from 0x03 to 0x0b
> 3. xx: changed from 0x06 to 0x49
> 4. xx: changed from 0x07 to 0x55
> 5. xx: static 0x96
> 6. xx: static 0x80
> 7. xx: static 0xa0
> 
> And I did play in Linux and could identify some fields :-) .
> 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
> 2. xx: this is the actual pixel clock
> 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"
> 
> Thomas

And I forgot to say that the center brightness sensor was used to do 
auto brightness control in the old gspca driver. Pixel clock was changed 
on the fly to get better brightness in dark light conditions.

Thomas