[Mplayer-cvslog] CVS: main/DOCS/tech mpcf.txt,1.7,1.8

[Michael Niedermayer]

Hi

On Friday 07 February 2003 12:39, Andreas Hess wrote:
> On Fri, Feb 07, 2003 at 12:20:55PM +0100, Michael Niedermayer CVS wrote:
> > Log Message:
> > zero_bit for normal frames, so we can distinguish them from other packets
>
> [...]
>
> > +zero_bit
> > +	MUST be 0, its there to distinguish non keyframes from other packets,
> > +	Note: all packets have a 64-bit startcode except non-keyframes to
> > reduce +	      their size, and all startcodes start with a 1 bit
> > +
>
> What about VLFH (variable length frame headers ;-))? I think often
> there will be a long stream of frames with nearly the same header,
> where for example just the lsb_timestamp changes. So you can use a
> mask (something like 00010) to distinguish that a particular frame
> header consists of nothing more than the lsb_timestamp.
yes, but there isnt that much in the frame header, its just 
the pointers to the next/prev frames
8bit flags (the zero bit is here too)
stream id (normally 1byte)
lsb_timestamp (normally 1byte)
the msb_timestamp & checksum are only coded for some frames so they dont count

... so only the stream id could be skiped, that could easily be done by a 
stream_id_flag in the flags byte, if noone disagrees then ill add that
but the gain isnt as big as it seems as the streams are inteleaved ...

[...]

Michael