[Ffmpeg-devel] Mpeg-4 playback: issues with CBR padding

[Mathieu Monnier]

Hi,

It's a late answer, but after rechecking the ISO/IEC standard, I may 
disagree with that :
> i dont think that stuffing macroblocks are allowed _after_ all macroblocks,
> the mpeg4 syntax places the stuffing mb in the mb type decoding loop and
> it seems like this loop must terminate with decoding a non stuffing mb
> which cannot happen after all mbs, that is my interpretation of the spec ...
>   
There are two cases :
  - the decoding loop of the macroblocks is a gob loop, in which case 
the statement is true ( since the pseudo code is : "for ( i=0; i < 
nMacroblock; i++ ) macroblock();" )
  - the decoding loop of the macroblocks is in a 
combined_motion_shape_texture(), in which case the pseudo code is : "do 
{ macroblock(); } while ( !resync_marker && !start_code );". In that 
case, padding after the last macroblock seems allowed, unless I 
misinterpreted something else ?

Regards,

Mathieu