[FFmpeg-devel] [PATCH 1/3] omadec: fix overflows during bit rate calculation

[Moritz Barsnick]

On Wed, Dec 14, 2016 at 01:02:41 +0100, Andreas Cadhalpun wrote:
> On 13.12.2016 08:11, Paul B Mahol wrote:
> >> -        st->codecpar->bit_rate    = samplerate * framesize * 8 / 2048;
> >> +        st->codecpar->bit_rate    = samplerate * framesize / 256;
> 
> Why multiply with 8 when dividing by a multiple of 8 directly afterwards?
> That's just a waste of computational resources.

I can only explain the term with "readability" (e.g. "number of bytes
times 8 is number of bits, divided by 2048 is the rate"). If you
bracket the (8 / 2048), it would avoid the overflow, and the compiler
should evaluate the term to that constant 256 anyway, right? (Just if
anyone cares about the presumed readability.)

Moritz