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

[Kyle Swanson]

On Wed, Apr 6, 2016 at 12:45 AM, Clément Bœsch <u at pkh.me> wrote:
> On Tue, Apr 05, 2016 at 07:01:14PM -0500, Kyle Swanson wrote:
>> Here's another audio filter. I hinted at this a few months ago, but I found out that
>> finishing the last 5% took almost as long as the first 95%. This is an EBU R128
>> dynamic loudness normalization filter. This filter uses libebur128 v1.1.0[1] and must be
>> configured with `--enable-libebur128'. Please also see the accompanying blog post[2]
>> which has an algorithm description, as well as some usage instructions.
>>
>> [1] https://github.com/jiixyj/libebur128
>> [2] http://k.ylo.ph/2016/04/04/loudnorm.html
>>
>> Thanks!
>> Kyle
>>
>> Signed-off-by: Kyle Swanson <k at ylo.ph>
>> ---
>>  Changelog                 |   1 +
>>  MAINTAINERS               |   1 +
>>  configure                 |   5 +
>>  doc/filters.texi          |  42 +++
>>  libavfilter/Makefile      |   1 +
>>  libavfilter/af_loudnorm.c | 905 ++++++++++++++++++++++++++++++++++++++++++++++
>>  libavfilter/allfilters.c  |   1 +
>>  libavfilter/version.h     |   4 +-
>>  8 files changed, 958 insertions(+), 2 deletions(-)
>>  create mode 100644 libavfilter/af_loudnorm.c
>>
>
> 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
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.