How to handle 4ch audio tracks with timeline waveforms?

Some time ago, I posted this thread:

But didn’t really get a resolution. However, I’ve since discovered the reason why the timeline waveforms were not working. The video footage that was showing this problem were from an Atomos Ninja V recording in ProRes 422. The Ninja V recorder has multiple audio channels and some did not have actual input, so the audio was being recorded on track 1, channels 3+4, while channels 1+2 were empty. In this situation, shotcut does not show a waveform in the timeline (no amount of “rebuild waveform” or disabling “high performance waveform” helped), even though there is audio on channel 3+4.

Under properties, there is a way to choose the audio tracks, but in this case, the 4 channels are all in track 1.

I have since figured out ways to workaround this.

The most obvious was to not record on the Ninja V where I didn’t have audio input, so the actual audio would end up on track 1, channel 1+2. This then does show waveforms on the timeline in shotcut.

Another workaround I had been using, prior to discovering the issue being related to multi-channel audio, was to run ffmpeg on my ProRes files and convert the audio to another codec. I didn’t know why this helped, but it did work. Now, knowing the root cause, I’m guessing the conversion to another audio codec must have been removing the empty channel 1+2 and channel 3+4 became channels 1+2.

So, although I can simply not record 4ch audio, I’m now curious what is the best way to handle audio tracks with more than 2 channels if one wants to have waveforms in the timeline? And is this behavior in shotcut correct or perhaps this can be a new feature request to handle multi-channel audio with waveforms?

Thanks for the reply, but this is a different situation. I have 1 audio track with 4 channels. Not multiple audio tracks.

channel or track what is the difference ? technically an media container contains the video source and a number of audio sources (tracks or channel is just different nameing). the audio can be recorded from the same source or be totally difference audio like different languages on a movie.
you can select the active channel in properties for the media, shotcut only the waveform for the active channel.
If you want more you have to detach the audio and select another one, like in the thread @Roy_Orbison links to above

My understanding is that a track can have multiple channels. For example, you can have an English language track and a Spanish language track. Each track can be recorded in stereo, so each track has a Left and Right channel.

My issue is if a track has more than 2 channels, say Left-front, Right-front, Left-rear, Right-rear channels, shotcut timeline can’t handle the waveform.

Ok, you are talking about surround sound, shotcut shows only one visual representation of the audio signal (RMS) it can be mono, stereo or some kind of surround sound (5.1). It can handle the audio but you only see one visial representation showning the summed audio (RMS).
You need a more advanded audio editor to making edits to the separate channels

@TimLau No, if that is how shotcut behaved, I would be fine with it. I realize there’s only 1 visual waveform to represent mono/stereo/surround channels. but my experience as mentioned in 1st post is that shotcut does NOT generate any waveform if you have the situation I described above. I was recording with 4-channels on a single track. it turns out, channel 1+2 had no audio input, so they were empty. my mic input was recorded on channel 3+4. in this situation, shotcut behaves like there’s no audio when it generates the waveform for the timeline. audio playback is fine though, i just can’t get waveforms in timeline.

to remedy this problem, i had to transcode the audio from 4ch audio to stereo (2ch audio) and then waveforms worked again. does that help you understand the problem i’m asking about? let me know if I’m not being clear…

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