[MEncoder-users] FGS (Fine Granular Scalability) in mencoder

[Rich Felker]

On Fri, May 12, 2006 at 09:44:44AM +0200, Guillaume POIRIER wrote:
> Hi,
> 
> On 5/11/06, Guilherme Dutra Gonzaga Jaime <gdjaime at land.ufrj.br> wrote:
> >Hi Folks,
> >
> >   I know that MPEG4 includes a neat feature that enables a user to
> >encode a input video stream to an output MPEG4 stream which includes a
> >base layer and a enhacement layer.
> >   The base layer is a (generally) low quality stream and the enhacement
> >layer includes the bits necessary to increase the video quality provided
> >by the base layer.
> >   A video server (stored stream) may send the base layer tot he client
> >and then choose how much of the enhacement layer to send (i.e.: To fit
> >to the network conditions).
> >   I've looking for the right options on the command line guides of
> >mencoder to turn this feature ON, but I failed to do so. The only thing
> >I think is near to this idea is the "two pass" coding presented by many
> >"howto"s.
> >  Is there anyone who could give me some information about enabling the
> >MPEG4 FGS feature through mencoder?
> 
> Sadly, I don't think any codec supported by mencoder can do it.

Not only is it impossible to encode such files; it's also impossible
to play them. This is one of the many "sounds good on paper but in
actuality is very stupid" features of MPEG-4, unlikely to ever be
supported by any encoder. The quality you'll get at a given bitrate
with this 'scalability' is WAAAAAY below what you'd get with ordinary
MPEG-4 at the same bitrate, so it's actually quite stupid and useless.

Rich