On 7/17/13, Jan Ehrhardt <phpdev@ehrhardt.nl> wrote:
Jan Ehrhardt in gmane.comp.video.ffmpeg.devel (Mon, 15 Jul 2013 06:47:48 +0200):
Would it be possible to insert the momentary value for volumedetect in the metadata and use that as input in af_volume.c? One pass normalization based on volumedetect should be faster than what we have now.
To answer my own question: Yes, that is possible. Since Nicolas problably does not want to tamper with volumedetect, I created a clone called af_volumeinject.c. See below.
Just like I now use volume=metadata=lavfi.r128.I this volumeinject allows me to use volume=metadata=lavfi.mean_volume. It is only a tiny bit slower than something like volume=-3dB, but faster than a two pass volumedetect + volume=-xx.xdB.
One thing came while testing volumeinject. I am really a novice in loudness and would have expected that volumedetect and ebur128 would report more or less the same value. They do not. They were 3-4 dB apart in my testfiles, with ebur128 reporting a louder value.
Because they are doing different things ...