[FFmpeg-soc] [PATCH]aacsbr: bs_amp_res is overridden by 0 for (bs_frame_class == FIXFIX && bs_num_env == 1) only for the current frame

Alex Converse alex.converse at gmail.com
Fri Nov 20 21:33:50 CET 2009


On Fri, Nov 20, 2009 at 3:20 AM, Robert Swain <robert.swain at gmail.com>wrote:

> On Thu, 2009-11-19 at 19:19 -0500, Alex Converse wrote:
> > So this is kind of ambiguous in the spec... bs_amp_res is read in the
> > SBR header. If (bs_frame_class == FIXFIX && bs_num_env == 1)
> > bs_amp_res is set to zero. Those are both per frame variables and I'm
> > pretty sure the affect only lasts for one frame. That's how the refdec
> > seems to behave anyway.
> >
> > 4.B.18.6 Data quantization
> > The spectral envelope scalefactors are quantized in 3dB steps or in
> > 1.5dB steps, dependent on the time frequency resolution of the current
> > SBR frame, and bs_amp_res. For the case where there is only one SBR
> > envelope per SBR frame and of SBR frame class FIXFIX, 1.5 dB steps are
> > always used, disregarded the value of bs_amp_res.
>
> Mmm, I see. Looks OK.
>
>
Applied.


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