theora dev - Feb 2008 - Gray scale video output from theora

hi all


I guess that *Theora* will convert the input color space (RGB or CMYK or
any) into YUV before it process and encode. (that means theora can operate
on several color space, but it get convert into YUV before process)

Is that true...?


I want to get a gray scale, encoded video output from the *Theora* encoder
while the input video is getting from a web cam (color input and gray scale
output).

*If the above is true.....(*theora use YUV color space*)*

it is possible that get a gray scale video output by just considering only
the Y component of the video (ignore the U and V components)

please give me your advices about how can I fulfill my requirement with
Theora.....?

-- 
-----------
Regards,
Janaka Priyadarshana
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On 16-Feb-08, at 5:33 AM, janaka priyadarshana wrote:
> If the above is true.....(theora use YUV color space)
Yes, Theora always encodes video in a YUV colour space.
> it is possible that get a gray scale video output by just  
> considering only the Y component of the video (ignore the U and V  
> components)
Using just the Y plane is a reasonable way to convert a YUV image to  
a monochrome one.

  -r

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On 16-Feb-08, at 10:05 PM, janaka priyadarshana wrote:
> int temp = 0;
>   for ( i = 0; i < yuv->uv_height; i++ ){
>     memset( LocalDataPtr, &temp, yuv->uv_width );
>     LocalDataPtr -= yuv->uv_width;
>     InputDataPtr += yuv->uv_stride;
>   }
In addition to Shane's comment, gray is u=v=128, not zero. That's the  
likely origin of the odd colours in your output.

  -r

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