[FFmpeg-user] Missing bitrate information on AAC encoded videos

[Moritz Barsnick]

On Sat, Mar 04, 2017 at 17:24:24 +0100, Marco wrote:

> i use to encode the audio of my movie using libfdk_aac, but in the
> result file doesn't appear the used bitrate (with mediainfo, ffprobe,
> etc.). I encode using CBR mode, in general matroska container.

Are you saying it also happens with other containers?

> Can please someone explains how i can see the bitrate of the AAC
> audio encoded with ffmpeg using such library and, in general, how i
> can make this information visible to the other softwares ?

I dare to say that other encoders/muxers give you the same issue with
AAC in Matroska. It's explained here:

https://github.com/mbunkus/mkvtoolnix/wiki/Meta-data-fields-like-bitrate-lost

I believe this is the issue: Matroska doesn't store per-stream bitrates
(unlike MP4, for example). So it's up to the reading application to
calculate or estimate the bitrate. Neither ffprobe nor mediainfo go to
the troube of parsing the complete file to calculate the bitrate for
you (because that's what they would need to do).

You may need to choose a different container to keep that info.

Moritz

P.S.: Perhaps ffprobe or mediainfo have options to calculate this data,
      I couldn't find them though.