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General (lossy) method for normalizing volume of any video file

I have an MKV video file (H264 video, AC3 audio) whose volume I need to normalize. Unfortunately, there doesn't seem to be any lossless way of normalizing the AC3 audio track. So I found out the general (lossy) way of normalizing the audio track of any video file is:

> ffmpeg -i input.mkv -vol nnn -vcodec copy output.mkv

nnn = 256 (no change)
nnn = 128 (half the volume)
nnn = 512 (double the volume)
etc.

This should work for any video file format that ffmpeg recognizes.

In addition, I can use the -map commands to remove any unwanted subtitles.

> ffmpeg -i input.mkv -map 0:0 -map 0:1 -ac 2 -vol nnn -vcodec copy output.mkv

This tells ffmpeg to only include track 0 (video) and 1 (audio) in the output file and ignore the rest.
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