Re: [Lame-dev] Re: frame sizes and bitreservoir

[Gabriel B. <bou...@mp...>]

Robert Hegemann a =E9crit :

> Hi,
>=20
> this is comming up again, as we always use the strict ISO mode
> in CBR 320 settings and that seems to be wrong. I'm thinking
> about when do we have to use the strict ISO mode and when not.
> The strict ISO mode is more an issue with hardware decoder
> than with software decoder. Poeple will upgrade software more
> often than exchanging their beloved dvd/mp3 hardware.
> Depending on the supported bit rate / sample rate we may
> weaken the strict ISO mode as we expect the decoder having
> some larger buffer.

I agree, we should probably not use the strict ISO mode by default=20
untill 321 kbps.
Our "relaxed" ISO interpretation seems to be practically safe.
Note: in my understanding freeformat requires all actual frames to be=20
the same size (modulo padding), so no bit reservoir for freeformat.

Something strange:
FastEnc is not using bit reservoir with 320kbps cbr, and they are=20
following the "strict iso" case (not the 7680 limitation). However, in=20
VBR they are using something similar to our relaxed ISO mode.

Bye,

--=20
Gabriel Bouvigne
www.mp3-tech.org
personal page: http://gabriel.mp3-tech.org