[FFmpeg-user] Normalizing audio wolume

[Marcin Czosnek]

Hey!

I am downmixing audio files (PCM) from 2.1, 3.1, 4.1, 5.1, 7.1 to stereo
using pan filter including LFE channel with following command:

./ffmpeg.exe -y -i testSample_PCM_48000Hz_8bit_2.1_FFMPEG_20s_Sine_0.wav
-ar 48000 -ac 2 -af "pan=stereo|FL=FL + 0.707*FC + 0.707*BC + 0.707*LFE +
BL + SL|FR=FR + 0.707*FC + 0.707*BC + 0.707*LFE + BR + SR" -acodec
pcm_s24le test.wav

I want to normalize output audio to -3db. In some cases value is overflowed
(look at test output below).

Test sample:
https://drive.google.com/file/d/0B8dhnSs8865hMnRfM3BBQk9Xdms/edit?usp=sharing

Test output:
https://drive.google.com/file/d/0B8dhnSs8865hQndfbWp2dXFxTkU/edit?usp=sharing

Kindest regards,
Marcin Czosnek