[NUT-devel] CVS: main/DOCS/tech mpcf.txt,1.117,1.118

[Rich Felker]

On Thu, Mar 02, 2006 at 04:29:50PM +0100, Michael Niedermayer wrote:
> Hi
> 
> On Thu, Mar 02, 2006 at 01:25:38PM +0200, Oded Shimon wrote:
> [...]
> > > > >      EOR frames MUST be zero-length and must be set keyframe.
> > > > >      All streams SHOULD end with EOR, where the pts of the EOR indicates the
> > > > >      end presentation time of the final frame.
> > > > >      An EOR set stream is unset by the first content frames.
> > > > >      EOR can only be unset in streams with zero decode_delay .
> > > > > +    has_checksum must be set if the frame is larger then 2*max_distance or its
> > > > 
> > > > I still feel this should be a seperate variable, the only reason you gave 
> > > > so far against it is that poor demuxers won't be able to decide... And IMO 
> > > > that's a very poor argument...
> > > 
> > > every additional field adds complexity, what do we gain here with that field?
> > > personally i would fix max_distance and not store it at all, as i fear people
> > > will set it to random values
> > 
> > ?
> > if (frame_size > 2*nut->max_distance)
> > 
> > if (frame_size > sc->max_size)
> > 
> > I fail to see the added complexity...
> > 
> > As for what do we gain - more freedom to the muxer, and the ability of 
> > limiting for ex. audio to a very small size and not increasing overhead, 
> > and limiting video to slightly higher to avoid additional overhead...
> 
> agree but only if we store all these max_size/distance stuff in u(16) so
> they cannot be arbitrary large

NO! They really need to be arbitrarily large! If you have a file where
each frame is at least 5 megs, max_distance is useless unless it's
well over 5 megs!

If people set max_distance too high for their content, that just means
their file will be very vulnerable to damage. This is a tradeoff that
belongs in the hands of the user. If I am storing a private file where
I insist on no damage and plan to throw away the file entirely and
restore from backup if even 1 bit is damaged, there is no sense in me
using a small max_distance.

You're welcome to make nutlint complain if max_distance is larger than
32k, but it would probably be good to avoid doing this if max_distance
is still smaller than 2*average_framesize or so.

Rich