I have video taken on smartphone, rather good.
When I create a clip out of it, I need to keep original audio which is important.
Audio quality is good when I listen to it in the shotcut (either playback of original video or clip preview). However, once I export my project, audio becomes seriously rattling on basses, like speaker is broken, if you understand what I mean.
I tried everything. From some moment I’ve just created a 10 second project with a small piece of source and did endless experiments with it, as export takes just a few seconds.
I tried different export audio formats, tried to set very high fixed rates for audio, applied different audio filters - result is nearly same, rattling remains.
Original clip is mp4 and audio properties are following:
AAC, 48000, format fltp.
Either I am missing something obvious or … ??
Another option you can also try:
Observe whether the audio peaks always correspond to the low frequencies (with the audio spectrum viewer (Shotcut-audio layout).
Then, if so, you can use the bass and treble filter. This filter has 3 frequency cuts (100 Hz - 1kHz - 10 kHz) and a good setting can make that -1 dB difference in the low frequencies.
This filter has no keyframe adjustment so the adjustment would affect the whole clip.
This filter has the advantage that you would lower the volume (you can also increase it) in one frequency range, while the other frequencies would remain unchanged.
If you want to maintain the overall tonal qualities of the sound track, then the
Gain/Volume filter as suggested by @kagsundaram is the way to go.
However, if you don’t mind changing the tonal qualities, then as @ejmillan suggested,
you can try and find out what is the frequency range of the sounds that are causing those peaks and reducing them a dB or two at a time.
It will most probably be the bass/drums, around 40 - 150 Hz.
Of course, that is only a guess.
Ideally what you should be doing, is using a compressor or limiter.
Ever so lightly, just keep in mind that a compressor and a limiter or two different animals.
Each case is different and calls for different “tools”.
Just remember that different attack and release times on a compressor will affect the
Golden rule, easy does it.