[FFmpeg-user] R128 ebur128 filter only for 48kHz?
t.rapp at noa-audio.com
Thu Feb 26 15:38:48 CET 2015
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".
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