[FFmpeg-devel] H.264 interlaced PAFF development and donations

[Gabriel Bouvigne]

Mike Melanson a ?crit :

> Step 0. Figure out what PAFF stands for.

PAFF is actually not defined into the H.264 standard. It means Picture 
Adaptive Frame/Field, to have an acronym similar to MBAFF (Macroblock 
Adaptive Frame/Field).

When encoding into interlaced mode (ie you are using interlacing but not 
MBAFF), you have to mention into the slice header if the slice is 
progressive or interlaced. Thus the standard allows you to use a mix of 
progressive and interlaced frames when using the interlaced mode.

As with previous standard interlaced is reffering to all frames beeing 
interlaced, and as the standard use the word MBAFF for the macroblock 
adaptive scheme, people started to call PAFF the ability to use both 
interlaced and progressive frames.

Practically, in PAFF you have:
*either a progressive or interlaced frame
*all macroblocks of the frame are of the same type (progressive or 
interlaced)
*you have to be carefull about ref pics ordering (but not more than in 
fully interlaced mode)

Regards,

-- 
Gabriel Bouvigne
www.mp3-tech.org
personal page: http://gabriel.mp3-tech.org