[FFmpeg-devel] [PATCH] avfilter: add loudnorm

Clément Bœsch u at pkh.me
Wed Apr 6 17:20:24 CEST 2016

On Wed, Apr 06, 2016 at 05:16:31PM +0200, Tobias Rapp wrote:
> On 06.04.2016 17:02, Clément Bœsch wrote:
> >On Wed, Apr 06, 2016 at 09:52:51AM -0500, Kyle Swanson wrote:
> >>On Wed, Apr 6, 2016 at 12:45 AM, Clément Bœsch <u at pkh.me> wrote:
> >>>Mmh. That's nice and all but... why not use/adjust the native ebur128
> >>>filter we have instead of relying on an external library?
> >>>
> >>>[...]
> >>>
> >>>--
> >>>Clément B.
> >>
> >>This could be an option for the future. We'll need to break all the
> >>EBU R128 logic out into utility functions
> >
> >why? what do you need exactly from the filter? The meta are exported in
> >each audio frame.
> >
> >>and update it to use the newest version BS.1770 so it can be used by
> >>both filters. Using libebur128 is a
> >>good option because it is widely used, actively developed, and updated
> >>whenever the spec changes.
> >
> >except it's an external dependency and we have code builtin available,
> >doing the same thing, and with no open issue (afaik).
> From the top of my head libebur128 additionally supports sample-rates !=
> 48kHz

The standard is (was?) only defined for 48kHz, although the filters
coefficients could be derivated for other frequencies. ff ebur128 could be
adjusted for that.

> and allows true-peak measurement (oversampling with the help of
> libspeex-dsp).

True peak is implemented in ebur128 (oversampling with the help of


Clément B.
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