I have a bunch of .mkv video files which audio is REALLY low volume.
How can i adjust the volume higher permanently in the .mkv file? preferrably with lossless methods (if even possible?).
Yes, i know i could just turn my speakers full volume, but then again if i watch some other video with normal sound levels, then my speakers would kill me!
I use FFMPEG (https://ffmpeg.org/download.html), a powerful free command-line tool. First, I analyze the video file with the command:
"C:\Program Files\ffmpeg\bin\ffmpeg" -i video.avi -vn -af "volumedetect" -f null /dev/null
In the output, I get something like
mean_volume: -24.8 dB
This means that to normalize the audio, I can increase it by about 24db. Here's the command to do it with FFmpeg:
"C:\Program Files\ffmpeg\bin\ffmpeg" -i myvideo.mkv -vcodec copy -af "volume=24dB" myvideo-boosted.mkv
Hope it helps!
Mkv is a container format that can hold almost any video or audio codec. You would need to figure out which audio codec(s) is/are being used in your files and see if any kind of lossless volume adjustment tool exists for that codec.
Using VLC is one option, but if you want to burn the file as a DVD to be played on a stand-alone player, that is not a suitable option.
You could use MediaInfo, as mentioned above, to determine the Video framerates & Audio bitrates, then configure Handbrake (https://handbrake.fr/) to use those values.
In the Video tab select the framerate that matches the original file via drop-down menu, select 'Constant Framerate (FPS) - leave 'Quality' unchanged and repeat in the Audio tab, matching the original audio bitrate then increase the gain (volume) via the drop-down menu ('v' shaped symbol next to the red X) in the audio options tab. Range 1-20. 10 should boost the volume to a reasonable level.
Not an elegant solution, but it works well.
another alternative is 'FFmpeg Batch' (freeware). You can import all your video files, then tell the program to copy the video stream and then edit the audio stream ... all using the Wizard on the main page. Then also on the main page their is an option to increase the audio by decibels. Just check the volume box, then increase the volume by between 5-10 decibels. Then just click on Sequential encoding button to encode ALL the files in the Queue.
You can use this tool to extract and insert the audio track. http://www.videohelp.com/tools/MKVtoolnix and you can use this tool to adjust audio levels http://www.howtogeek.com/howto/20700/how-to-adjust-the-volume-of-your-mp3-files/ .
Note: I have not used these programs since I have not had this issue, but these pieces of software seem to be able to do what you have requested.
Rather than re-encoding the sound, you could watch the videos in VLC. The volume control in VLC goes up to 200%. Normal full volume is 100%, and then after that it adjusts the volume in software.
In other words, you can boost sound that is recorded at a too-low level without having to turn the system volume or your amplifier volume up too high.
