[FFmpeg-user] R128 ebur128 filter only for 48kHz?

Clément Bœsch u at pkh.me
Thu Feb 26 16:40:33 CET 2015

On Thu, Feb 26, 2015 at 03:38:48PM +0100, Tobias Rapp wrote:
> On 25.02.2015 16:29, Clément Bœsch wrote:
> >On Wed, Feb 25, 2015 at 10:35:59AM +0100, Christoph Gerstbauer wrote:
> >[...]
> >>What is the actual state of the ebur128 filter? Is just 48kHz still
> >>implemented or are there more sampling rates implemented since 2013?
> >>
> >
> >Yes ebur128 supports only 48kHz because that's the only one standardized
> >(at least when it was implemented; did this change?). I saw some people
> >generalizing the formula for other frequencies, but until this is official
> >I don't see much point in supporting that. Of course, patches are welcome.
> ITU-R BS.1770-2 states (page 4):
> """
> These filter coefficients are for a sampling rate of 48 kHz. Implementations
> at other sampling rates will require different coefficient values, which
> should be chosen to provide the same frequency
> response that the specified filter provides at 48 kHz.
> """
> I read this as "feel free to use a different sampling rate but you will have
> to calculate the filter coefficients for yourself".

I feel very lazy right now to look for the formula themselves, but if
someone have a reference for the 2 filters then I can send a patch to
implement them.

Clément B.
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