[Ffmpeg-devel] ffmpeg & postprocess_internal.h (colorspace issue)

Kris A. Wotipka kris
Sun Jul 24 05:43:06 CEST 2005


Just realized that you are the one who wrote the postprocess_internal 
source.  Can you tell me what the line

/// select between full y range (255-0) or standart one (234-16)
#define FULL_Y_RANGE    0x8000                  // 32768

is for?  You can reply here or off list but it is making my brain hurt. 
  I am understanding now that I need to go to the YUV space with this 
now.  I am still trying to figure out the -pix_fmt yuvj420p is all 
about.  I am having a hard time finding docs on it.  From what I am am 
seeing, this throws it into PAL.  Are there some docs hidden somewhere 
that are additional to the ones that come with ffmpeg / or man ffmpeg.

Also, I am trying to figure out the compile sequence for this.  Should I 
compile the libpostproc then libavcodec then ffmpeg or if I make changes 
say to something in libavcodec do I need to recompile ffmpeg.

thanks again


Michael Niedermayer wrote:
> Hi
> On Saturday 23 July 2005 00:13, Nico Sabbi wrote:
>>Michael Niedermayer wrote:
>>>>Greetings all,
>>>>In a nutshell, I need to process .vob and mp2 video files that are in
>>>>"full Y" (luminance range is 0-255) to .mp2 with the "standard" luma
>>>>range of 16-234.
>>>maybe you should look at mencoder, more specifically the eq/eq2 filters
>>>or try something like
>>>ffmpeg -i <input> -f rawvideo - | ffmpeg -f rawvideo -s <size> -pix_fmt
>>>yuvj420p -i - -y <out>
>>is the attached patch to ve_lavc.c enough to accomplish the task and
> no, lavc wont convert anything if the pixel format is set to something not 
> directly supported and mpeg2 IIRC has no 0-255 vs. 16-235 flag
> [...]

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