Is there a way to normalize audio volume in multiple MKV videos?

[dannieboiz]

I have thousands of MKV karaoke tracks with dual audio. Some videos are louder than others vice versa.

Is there a way to make them all the same level?

[JVRaines]

I would use FFmpeg's dynaudnorm filter in a batch script loop.

[hello_hello]

What format is the audio? If it's AAC or MP3, foobar2000 can run a ReplayGain (TrackGain) scan and losslessly adjust the volume without having to extract the audio.
That doesn't apply compression. It simply adjusts the overall volume of each track for the same target volume. It's under the ReplayGain right click menu and to adjust the volume losslessly you'd use the "apply track ReplayGain to file content" option.

The default target volume for ReplayGain is 89dB (which is really a sound pressure level and translates to a volume of -18dB). I'd stick with the default target volume unless you have a reason to use something else.

There's a right click menu item under "Utilities/Select Stream" for choosing the audio stream to be decoded. I assume it also applies to the ReplayGain scan, so you'd have to highlight all the files you've opened, select a stream, run the scan, save the data, adjust the volume, then repeat for the second stream. I haven't batch adjusted MKVs with multiple streams myself, but logically that's how it'd work. And it only works for AAC or MP3. All other audio types have to be re-encoded to physically change the volume.

[pandy]

What format is the audio? If it's AAC or MP3, foobar2000 can run a ReplayGain (TrackGain) scan and losslessly adjust the volume without having to extract the audio.
That doesn't apply compression. It simply adjusts the overall volume of each track for the same target volume. It's under the ReplayGain right click menu and to adjust the volume losslessly you'd use the "apply track ReplayGain to file content" option.

It adds/modify metadata information that can be ignored by decoder as this type of metadata is not mandatory to be implemented at decoder level...

The default target volume for ReplayGain is 89dB (which is really a sound pressure level and translates to a volume of -18dB). I'd stick with the default target volume unless you have a reason to use something else.

89dB of what? -18dB of what? dB is unit-less and describe ratio...

[hello_hello]

What format is the audio? If it's AAC or MP3, foobar2000 can run a ReplayGain (TrackGain) scan and losslessly adjust the volume without having to extract the audio.
That doesn't apply compression. It simply adjusts the overall volume of each track for the same target volume. It's under the ReplayGain right click menu and to adjust the volume losslessly you'd use the "apply track ReplayGain to file content" option.

It adds/modify metadata information that can be ignored by decoder as this type of metadata is not mandatory to be implemented at decoder level...

Yes, fb2k can add/modify metadata information, but it can also physically adjust the volume of MP3 and AAC audio. As MP3Gain does. My MP3 player doesn't support ReplayGain, so for years I've been using the ReplayGain data to physically adjust the volume instead. First with MP3Gain, and now with fb2k, because fb2k supports adjusting the volume when the audio is inside an MP4 or MKV container (and maybe other containers, I've only tested MP4/M4A/MKV).

The default target volume for ReplayGain is 89dB (which is really a sound pressure level and translates to a volume of -18dB). I'd stick with the default target volume unless you have a reason to use something else.

89dB of what? -18dB of what? dB is unit-less and describe ratio...

89dB is the official ReplayGain target volume. It's a sound pressure level and meaningless to mere-mortals, but that's how the target volume is described. I'm not responsible. In fact, I recently suggested it's time to stop referring to the volume that way in the fb2k forum, and while I'm sure it's inevitable, it's not going to happen just yet.
https://en.wikipedia.org/wiki/ReplayGain#Target_loudness

I thought it'd be fairly obvious -18dB refers to a volume below "full scale". I almost typed -18 LUFS instead of -18 dB, but most people understand -18 dB is located a little lower than 0dB on their player's output meter, whereas LUFS often requires explaining.
So..... LUFS = loudness units relative to full scale. It can be used interchangeably with dB in this case.

[dannieboiz]

Hi Guys,
finally have sometime to look at this...

So I ran a couple test tracks, question about Foobar2k, does it actually alter the gains of the track or does it just add a tag so the player can appropriately adjust the playback volume? Is this going to affect the overall sound quality of the tracks? Since each track in the video file will be different, will it do the gains for each track in the video?

[dannieboiz]

btw... the tracks are mostly in MP3 format