[XviD-devel] OBMC decode support patch for dev-api-4

[suxen_drol]

On Fri, 9 May 2003 17:38:52 +0200 (CEST) Christoph Lampert <chl at math.uni-bonn.de> wrote:
> On Thu, 8 May 2003, suxen_drol wrote:
> > 2) decoder->encoder messaging format is not defined within mpeg4 visual
> > iso. however i believe its describe in the rtp handling specification.
> 
> That one?
> 
> http://www.cmlab.csie.ntu.edu.tw/~pkhsiao/RFC/rfc1889.txt
> 
> "RTP: A Transport Protocol for Real-Time Applications"
> 

actually, futher reading reveals the upstream ("decoder -> encoder") 
message format is included in the mpeg-4 iso. however the transporation
of this message is left undefined. 

anyway, to support arts its not neccessary that the encoder (or decoder)
support newpred. newpred is only used when the an error in the bitstream
is detected; if the encoder doesnt support newpred, the decoder will
have to wait for the next ivop.

"It requires an external framing mechanism for synchronization of the
messages within the upstream, as the backchannel syntax defined herein
contains no synchronization flag words. This synchronization is provided
by the lower layer such as ISO/IEC 14496-1:1999 (MPEG-4 Systems)." --
ISO/IEC 144996-2 page ~426.

-- pete