[LAD] Replaygain for video?

Philipp hollunder at lavabit.com
Fri Dec 9 20:20:30 UTC 2011


Hi there,
I could use some advise.

You may or may not heard of replaygain. It's reasonably widely used in
consumer audio, but sometimes I wish it was available for video as well.
By this I mean I wish it was available for the audio part of the video.

Well, I need a programming project for a university course and this is
just one of my ideas that I want to propose to my teacher and
prospective teammates. In order to do this I'd like to narrow it down a
bit further and especially want to find out whether I have the right
idea of how it can be achieved.

Scanning/tagging
Since replaygain works on whole audio files I think I need to extract
the whole audio track from the container. How easily this can be
achieved I don't know. After that, the scanning process should work as
with any audio file. Afterwards the calculated replaygain values have to
be added to the metadata of the file. I have no idea how hard it is to
add new metadata fields to video formats.

Playback
Video players need to be aware of those tags, read the metadata and scale
the playback volume accordingly. This is probably not hard per se, but
there are many players out there. However, I plan to start with a single
player, even with a single file format, and go from there.

Question 1: Is there anything better than replaygain that should be used
instead?

Question 2: Which player would be easiest to hack to add such
functionality? Could it be a gstreamer plugin? mplayer?

Question 3: How much work would it be?
The project should be done in C++ if possible, otherwise C. Group size
2-4 Students, all rather new at C/C++ and rather inexperienced in
general.

Other ideas I have are in short:
- A CLI (using readline) connection manager for jack audio/midi and alsa
midi that can handle large numbers of ports. More detailed ideas exist
thanks to Julien Claasen.

- A simple but hopefully sane mplayer GUI

- A new GUI for ecasound

Another problem I might have is that most students in the course are
Windows users, not sure whether I can go solo.

Thanks for any advice,
regards,
Philipp




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