Mixing two audio channels?

I think this is a somewhat meaningful question: does Shotcut support any form of audio mixing?

Specifically, I have some motorcycle helmet cam video. The audio is from the mic inside my helmet. (details on request) I want to mix music into the video while retaining the motor sound. I think this works out as a video track and two audio tracks. A1 is from the helmet cam, A2 has the music. V1 and A1 will be fully edited so there’s no issue of subsequent edits causing problems on A2 (music).

I suppose I can strip the audio from the video, mix the sound with, for example, Audacity, and then restore the mixed audio back to Shotcut as A1 (and, of course, no A2 track).

Following the tutorial on working with audio tracks, I can see how to move a single clip. However I have a set of three clips with transitions in between. I don’t see how to copy the entire audio track (including transitions) to the active audio track.

I mixed the audio track in Audacity and dropped it into my Shotcut project. I’m to the point where I can play the video with the new audio track. All that remains is to combine the video track and the audio track into one complete video/audio unit that can be exported to be burned on a DVD.

I simply don’t see how to move the complete video, with three transitions, to a new video track. I can do it clip by clip, from the source video track to the destination track. That’s fine a small, uncomplicated projact. But a long, complex track??

How do I move the desired audio into the same track as the video? I tried copying the audio track and pasting it on the video track. That doesn’t work; the copied audio track is simply added to the video track.

Seeing as how you have put a lot of thought into this I feel guilty for saying it, but it’s really not necessary that you condense all your work into just one track. Shotcut can export multiple tracks at once into a video file, say like a .mp4 that you can burn onto a DVD from there…

If there is some specific reason you’re so determined to combine all of this into just one track I’m missing it. :confused:

I started with a single video of a motorcycle ride. I cut it into three clips. I put the clips in a video track, which brought the audio along, of course. I created two transitions to fade from on clip to the next. The audio track was, I assume, suitably edited when the transitions were made. Now the fun begins.

I want music over the existing audio (engine and wind noise). Does Shotcut support audio mixing?

Not knowing the answer to that question, I exported the audio track, mixed it with Audacity, and imported it back into Shotcut. Now there’s a video track, with its audio, and an audio track from Audacity. (video and audio are synced but I have a question about that - I’ll start a new topic).

If I understand your reply, if I mute the edited video track’s (unmixed) audio track and export the tracks, I’ll get the video and my mixed audio, imported to the project after editing the video. Have I got it right?

As a point of curiosity, how would I duplicate the edited video track into another video track?

Yes, it automatic mixes audio between all tracks except the ones that are muted.

Manually, by selecting each clip on the from line, copying it, and pasting it to the other track.

You can’t.

I think you are making this more difficult than it needs to be. Shotcut tries to keep it simple, but you appear to be working against it or asking for too much. It does not do everything, and if it did, it would probably even more confusing to use! If you do not want the audio from your video track, then simply mute it.

I’m finding my way through most of the production process. NTL a “handle (copy, move) all selected clips and transitions at once” tool would be welcome. Also, I may well have missed it, but, short of doing the math, I don’t see a quick way to get the timing (start, length, end) for transitions.

I wound up using Audacity to build the soundtrack. The biggest challenge in that process is to get the timing for the cues straight. A lot of note-taking of video timing is a must.

If you use audacity you can export each track in shotcut as an audio file(called stems). And import each track in Audacity. If you want to make sure that the sync isn’t sliding you should add a count down leader with a “blob” sound at “2” into each track, so they can be used to align each track.

Another way is to do the same in Ardour which also allows you to import a video track, so you’ll be able to work in a/v sync.

I hope edl import will be added to Ardour at some point so you could import your shotcut project into Ardour. https://community.ardour.org/node/13913

Blender can be used to convert .edl to .Ardour but there is an unaccuracy in the Blender edl import script: Editing sound from Shotcut in Ardour

Strictly speaking, “5-4-3-BEEP” poses the same problem: aligning the audio and video tracks by eye. OK, expanding the area of interest helps, but it’s still done with the MK-1 eyeball. Audacity can resolve timing to a zero crossing point. Hence my question. Does Shotcut have a tool to ensure the start of an audio track (key word ->) exactly with the start of a video clip?

The same applies to the end of the clip. Take a simple jump cut to begin with. Clip ends, audio ends at exactly the same point. Now, the harder situation. clip-transition (cross-fade or wipe or… not a jump cut). The audio track should end at exactly the end of the transition, with new audio at the start of the transition (let the transition do the crossfade). Again, the basic question does Shotcut have a tool to place both tracks exactly when the audio track is imported (or, I suppose vice versa - imported video, existing audio).

Long question for, I hope, a short answer. :slight_smile:

I’m new to video editing software in general and Shotcut was the only editor that I start really using to edit my videos. Do other video editing software have the kind of tool you are asking?

No, Shotcut does not have these tools. It has bugs, compatibility issues, and rough edges that need fixing. Those things have been the priority for most of this year. Maybe I can start working on features again soon.

Just checking with Shotcut included countdowns(Open other > Count), I realize that the beep/blop is not strong enough to produce a spike in the waveform, so it is not possible to do what I mentioned above(and maybe the exact blop frame could be inverted color vise).

Some years back I did some in Avisynth and uploaded them to Youtube: https://www.youtube.com/results?search_query=tintwotin+countdown

Using those files instead I get a spike(so maybe you can download and use one of those instead):

The audio pop produced by the countdown generator (Open other -> Count) is a 1kHz tone with a duration of exactly one video frame. The level of the tone is 0dBFS. It quite literally can not be be any louder. Open the audio waveform scope and look at the audio waveform to see what I mean.

Maybe you need the duration of the pop to be longer?

If the blop is visible in the waveform then all is great(except my eyes).

This is what I see when playing the clip directly in the source player:

This is what I see when playing the clip in the timeline:

It looks like the level of the sound is reduced by 6dB when in the timeline. This is probably due to the mixing of audio among tracks. Each track must be reduced to avoid peaking when they are combined. I can’t think of a way to work around that to get back to 0dBFS. So it may be that -6dBFS is the highest that is possible when using the timeline.

Re: Imported audio and mixing, Snap is working after all. For some reason it wasn’t originally, even thought the “magnet” icon appeared to be enabled. For mixing, the gain filter does the needed work. But… sure would be nice to have gain work in real-time instead of adjust, restart playback adjust, restart, wash-rinse-repeat. Also, a knob control seems a better UI choice than the slider/type-in currently in the filter.

For me, at least, the question is answered.