[FFmpeg-devel] [PATCH]Higher default mpeg muxrate for large dimensions

Michael Niedermayer michaelni at gmx.at
Wed Jan 18 05:34:50 CET 2012


On Wed, Jan 18, 2012 at 03:07:41AM +0000, Carl Eugen Hoyos wrote:
> Michael Niedermayer <michaelni <at> gmx.at> writes:
> 
> > > -                stream->max_buffer_size = 230*1024; //FIXME this is
> probably too small as default
> > > +                stream->max_buffer_size = FFMAX(st->codec->width *
> st->codec->height, 230*1024);
> > 
> > iam not sure about this, its a bit hackish but probably ok as long as
> > the standard resolutions never result in too large buffers
> 
> What would be too large?

I think the one specified is the largest allowed for DVDs,
SVCD & VCD have smaller ones

I dont have the specs so i cannot say for certain what they say.


> 
> > also the max buffer size that can be stored in the file should not be
> > exceeded
> 
> And what is the max buffer size?

for video 8387584 byte is the max that can be stored in the field
iam not sure what standard allows this though.

If one is encoding mpeg-ps with the intent to have a standards
compliant file then its needed to know what standard and whats
written in that standard.
that then says max/min rate & buffer size and with these values
encoding should work.

We probably should make the encoder fail if someone tries to set a
buffer size without max rate
because this combination makes no sense.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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