[Vorbis] What's the value range of float samples?

Nikos Chantziaras realnc at gmail.com
Fri Jan 11 10:11:23 PST 2013


On 11/01/13 18:53, Gregory Maxwell wrote:
> On Fri, Jan 11, 2013 at 10:41 AM, Nikos Chantziaras <realnc at gmail.com> wrote:
>> Are there any smarter strategies for doing this?
>
> Yes, a limiter.

Oh.  I thought a limiter is only needed for mixing several audio streams 
together, not when decoding a single stream.

Does ov_read() use a limiter, btw?


> For opusfile (the analogs api to vorbisfile for vorbis) we've talked
> about including a limiter— Opus' more sophisticated lossy compression
> tends to cause a bit more peak inflation than Vorbis' does— and we'll
> probably do that eventually.  Generally my recommendation for best
> practics is twofold:  Encode things at a pre-normalized loudness that
> has enough headroom (either at replaygain or EBU R128 levels) so that
> clipping is almost never a concern, and apply a limiter just in case.

The general method of encoding seems to be ripping from the CD into a 
WAV file, and then "oggenc mytrack.wav".  At something like -q5, one 
would expect transparent results.

So what you're saying is that this is *not* good enough?



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