Nested timeline audio bug/glitch

So I have a "Timeline Main" where I have all my edit. A few audio tracks (some mono, some stereo) with EQ, plugins, dynamics, etc ... It's 30 fps FullHD, the project settings.

This main timeline renders fine. I did an "audio only" export and it's good. It also plays just fine in the UI.

Now I create another timeline (let's call it "Timeline Demo"), also project settings, 30 fps FullHD. I include the "Timeline Main" in it and chop it up, only keeping some excerpt from it a little bit everywhere.

If I render that "Timeline Demo", the audio is messed up. I mean not completely, it's like 95% fine but every few seconds there will be a glitch, either a crack, or a discontinuity, a bit of repeated audio, ... something.

I ended up taking my "audio only export" of main and using that as the audio track (cutting it at the same point I did the nested timeline) and that exports fine.

So something is wrong when rendering the audio of a nested timeline :/


Resolve 17.1.1 running under linux with RTX 2070 Super (driver 460.73.01).
I render to MOV GrassValley HQ / PCM 16b 48 kHz.

I've seen others report issues with nested audio as well.

Yeah, doing a search here in the forum seems to indeed show a lot of that.

Following one of them I tried to disable the Limited I had on the main bus output of the inner timeline and I actually managed to make a working export with that (at least AFAICT). Not sure if that's 100% reliable, will have to see for future ones.

Still would like to see that fixed quite quickly because the "decompose in place" is not much of a workaround if you have a lot of work in fairlight since that's not copied over when decomposing.

With no way to predict when a fix will appear, might be worth changing how you do things in future projects.

Don't nest.

Well that's easy to say but I couldn't really think of any other way to achieve the same result ...

The inner timeline is the "real" product / final project. But it takes like 5 hours to render.

The outer timeline is where I cut up small chunks of that final project just to test the render of a few shots and send to others for review. And that one at least renders in like 5 min.

* "In/Out points": you can only have 1 so I'd have to do 10 independent renders (reselecting in/out each time) and then stich them up each time.
* "Decompose in place": As stated, that doesn't keep the fairlight config / plugins / etc for all the tracks. Also when I update the main timeline, I'd need to redo the decomposing.
* Duplicating the main time line and cutting parts out : Doesn't work, there is a bunch of fusion clips on there that are parametric to the composition length so if you slice them, it changes what is actually rendered ...

I'm open to other alternatives ...

One day later and 17.2 dropped! Very unpredictable.

That failing, then separate In/Outs is probably your best option. You can add them to a playlist in a media player, no need to actually combine them into a single file for review.

I can attest to this issue too, and the offered workaround of decompose in place, as a good temporary fix.

I wonder if this fix listed in the 17.2.2 BUILD 4 release is related:

• Addressed an issue with decoding some 24-bit linear PCM audio files.

For what it's worth, the issue for me has been with 32-bit PCM.

I can confirm that I'm still getting those audio glitches in 17.2.2 BUILD 4.

Rather than re-rendering the whole video + audio again after "Decompose in place" on the audio (because time), I just re-exported the audio. If it helps anyone, to re-insert the corrected audio back with the video file replacing the glitchy audio, the ffmpeg command is as follows:

Code: Select all

ffmpeg -i my-video.mov -i fixed-audio.wav -c:v copy -c:a copy -map 0:v:0 -map 1:a:0 my-video-fixed-audio.mov

I too am experiencing multiple audio glitches with nested timelines. Two I've noticed so far:

1. "Stuttering" - like an actor appearing to say the same word or half word twice in quick succession. Didn't show up on Edit, on either the nested or outer timeline, only in the final deliver.

2. Offset/out-of-sync audio: audio slightly delayed in the outer timeline, such that lip sync is noticeably off.

In my case I have a 2.5 hour long project consisting of 16 separate scenes, each in its own timeline. I then have my All timeline which is currently just these sixteen timelines arranged sequentially, with no further changes.

I can't use Decompose because some of these scenes now have Fairlight track plugins and other Fairlight effects. By the time I'm finished with this project, all scene timelines will have these effects.

So my workaround thus far is simply to render out all sixteen individual timelines, import the resulting files, and do a final render with the sixteen files stitched together.

This is very tedious and time consuming, made worse by the fact that there's no way to do bulk renders - I can't select all 16 Timelines and "Add To Render Queue" at once. I have to click through them one by one in Deliver, adding each individually. I suppose if this problem persists I might have to investigate writing a Lua script to automate this.

(One thing I haven't tried is rendering the All timeline in Individual Clips, to see if this still causes the nested audio problem or if this might be a batch-render workaround)

Did anyone check if this is fixed in 17.3.1 ?

Did anyone check if this is fixed in 17.3.1 ?

I had noted at least one occasion last week the glitch occurred. It doesn't seem to be happening as frequently as it had been at least, as this video despite using nested timelines and many cuts, only had one notable glitch.

I've yet to try again with 17.3.2 BUILD 8, which I updated to today.

Curious... has anyone found a resolution or fix to this audio glitch problem when using nested timelines?

It's happening for me on 18.5. I too am using a "render timeline" which contains all my nested segment timelines. Each segment renders fine from within its own timeline, but two (dang... now three) of my eight segments have consistent & repeatable audio glitches when rendered from the "render timeline". Audio stuttering/repeated words bouncing from left to right, and occasional crackles. Re-creating the problematic segment timeline worked once, but not a second time it seems.

Don't nest.

Is this still the prevailing wisdom?

I'm on DR Studio 18.4 Build 41 running on Win 11 with an i9 12900K + RTX 3090.

Is this still the prevailing wisdom?

Another user reported an issue with nesting just today, so...yes.

Don't nest.

I wanted to jump on the bandwagon here and report that I'm having the same problem with audio glitches after render. However, glitches consistently happen for me with and without nested timelines ***WHEN*** the render is longer than somewhere around three minutes. Changing from MP4 to Quicktime, AAC to Linear PCM (24 bit) did not help.

What ***DID HELP*** was rendering each (smaller) timeline individually, then compiling them in a new project with same settings for a final (long) video.

I hope there is a better workflow that I don't know about yet.

Mac Studio, Apple M2 Ultra, 64GB, macOS Sonoma 14.1.1

I'm having the same problem with nested timelines and would really like to see this fixed. I'm working on a TV show that needs multiple people working on various segments of the show. Using nested timelines helps quite a bit. Please let me know any updates.

Don't wait for a fix here, Tom. Change your work flow.

You can still work on scenes in separate timelines. But Copy/Paste the clips into the Master instead of nesting.

For each nested timeline bounce the final mix. Timeline > Bounce Mix to Track

Then make sure the new track is the only thing feeding into the final mix, and that no effects are applied to it.

For each nested timeline bounce the final mix. Timeline > Bounce Mix to Track

Then make sure the new track is the only thing feeding into the final mix, and that no effects are applied to it.

This should work unless there is also some issue with nested video clips (there are some effects that don't work well nested, apparently).

unless there is also some issue with nested video clips

There are such reports.

Don't nest timelines.

It's the only safe play.

Nested video issues are few and far between because compound clips with nested video effects are supported (and a nested timeline is treated like a compound clip). However, there are a couple of video effects such as those fade handles that don't work correctly even with compound clips. Nested audio effects are a different ballgame - they appear to be a total mess.

I do agree that avoiding nested timelines is the safest (and least error prone) practice.

[Peter Chamberlain]

We are reviewing the nested timeline reports but it would really help if everyone listed their exact resolve version in their reports.
It's also helpful to know if voice isolation or other processing is within the nest.

Hi Peter - I am running 18.6.3 Studio on my MacBook. I don't usually nest timelines but thought I would for the sake of testing (per this thread). In my nested timeline I invoked voice isolation of a clip and found that it caused hiccups in the master timeline as well as prevented drawing waveforms in the master timeline. I'll do some more testing to see if I can get it down to a few simple steps and report back here.

Add - I tried again with just a couple of short clips on a nested timeline and found that there was a delay in redrawing the waveforms at the master timeline level but once they were drawn, the audio playback was fine. In my original test I was using a Multicam clip on a nested timeline and within the Multicam clip I had tried the voice isolation on a clip and this messed things up at the master timeline level.

Add 2 - The weirdest thing - I created a nested timeline with two stereo audio tracks and left A2 empty and on A1 I applied voice isolation to a clip. In the master timeline there were hiccups and almost and echo delay of the audio track. If I moved the audio clip in the nested timeline to A2 everything was fine in the master timeline.

I've been using DR almost every day for the last 3 years and I've been noticing:

1. Audio inside compound clips are prone to glitches (as many folks here have testified to)
2. Audio clips with Voice Isolation effect applied are very prone to glitches. On a collaborative project, even if it plays back well on one machine, when playing it back on another machine you can hear the glitching happening live. (In this case I don't remember if it was inside a Compound Clip or not)
3. Two audio clips put back-to-back is also prone to glitches after export - which really frustrates me. A single audio clip starting flush from zero produces glitches too. So your first frame of video kinda opens with a bang. Not every time after rendering, just randomly out of the blue. Our for-peace-of-mind workaround has been to add a small crossfade at EVERY AUDIO CLIP, and the issue is no longer there.

Screen Shot 2024-03-02 at 11.31.00 AM.png (22.74 KiB) Viewed 1722 times

Screen Shot 2024-03-02 at 11.31.11 AM.png (25.44 KiB) Viewed 1722 times

BUT it shouldn't need to be like this. I'd say over the years we've wasted hours re-rendering entire products because of these audio glitches. (Some of the problems I describe might have happened while using older versions of DR. But on the current newest version, some of them definitely still exist)

BM please find the source of these audio glitches and fix it, it's been a plague for us. Thank you for your work.

MacBook Pro M1Max running Monterey
DaVinci Resolve 18.6.5

If you are having audio studder occur in your nested timelines due to the use of Voice Isolation then go to the fairlight tab, select the audio clips that are studdering, right click and select "Cache Audio Effects". A check mark will appear in the contextual menu next to "Cache Audio Effects" letting you know it is active. If you ever need to turn it off, just select it again and the render cache for the audio will be removed.

This completely got rid of all the audio issues I was having with my nested timelines. Just make sure your seams in your audio files are crossfaded or faded. Any where in your audio file where you have made a cut that does not occur at zero crossing (in the wav file) you will here the standard "pop" after caching the audio effects. So I'd suggest tightening everything up and getting it how you like it and then caching. But no worries if you need to edit the audio again. You can either uncheck the "Cache Audio Effects" option and make changes or you can just change it and deal with the pop up window. I'm not sure why after caching the effects that any new edits have to be done through a plugin window, but it does. Until I know more about how that works I just avoided it. I turned off the caching, made my adjustments and then recached it.

For me it was not an option to simply not use nested timelines. We wanted all passed episodes to be updated with new changes that were being made. To have to individually make edits to 15 different episodes would be really inefficient. This way I preserve the efficiency of nested timelines and fix the audio issues.

If you try this let me know if it works for you.
God bless.

Running resolve 18.6.3 Build 19

Nothing fancy going on, multi track composition with only reverb effects on a couple channels. No dialogue isolater, but its glitching out if I nest it. I have another version that is fine when nested using the exact same track layout and effects so cant figure out what the cause is.

We are reviewing the nested timeline reports but it would really help if everyone listed their exact resolve version in their reports.
It's also helpful to know if voice isolation or other processing is within the nest.

Hi Peter, did anything come about from these reports? We're still experiencing this issue and it's embarrassing when clients find glitches in their webinars, and we can't watch 1hr long videos in full every time we render out the video so we've had to workaround by decomposing all CCs, but this makes a mess of our workflow and timeline.

We are reviewing the nested timeline reports but it would really help if everyone listed their exact resolve version in their reports.
It's also helpful to know if voice isolation or other processing is within the nest.

Confirm this is a major issue that's been driving me nuts since Voice Isolation was introduced. It's such an awesome feature, but a real hassle to use because of the distortion issues.

I'm currently using both the "cache audio" and cross-fade workarounds, but I _still_ get random pops in the final render every so often -- usually at least once or twice in a 10-minute video.

We are reviewing the nested timeline reports but it would really help if everyone listed their exact resolve version in their reports.
It's also helpful to know if voice isolation or other processing is within the nest.

Hi Peter,

I can actually recreate the glitch at will. and to clarify the glit will be a "matrix cat" style repeated bit of audio in a seemingly random place down the timeline from a segment that was time-remapped (e.g. putting in a 1 second freeze frame in the nested timeline) the glitch also does render out to the final.

1) Top Level Timeline (shown in picture below):

1. titles
2. subtitles
3. score (ducked by dialog+zingers from addons)

2) Add Ons (Type: Timeline; Nested in Top Level)

1. retimes e.g. freeze-frames and such.
2. voice isolation
3. dialog leveler are added.
4. "stickers and sfx added here too

3) Edit (Type: Compund; Nested in Add ons)

1. Rough-edit decomposed as clips from multi-cam
2. one minor "creative audio hack" and 6 frame cross fade.

I have not tried to remove all the extra stuff - but here's a snapshot showing the top level timeline with the workaround that works (duplicate the audio track only, decompose to clips.

zoom in on timeline where the glitch occurs

2024-05-05_14h30_38.jpg (282.16 KiB) Viewed 1038 times

1. glitched regular nested audio
2. decomposed audio (missing the sfx layer)
3. score that's ducked by (1),
4. this is another workaround *see below
5. sfx for completeness

* the second workaround is to go down to the rough edit compound clip and select just the audio tracks and make another compound clip. insert that on the top level timeline. then copy the retiming from the "add-ons" layer and paste the timing to the new compound clip. this would also put the voice isolation and dialog leveler on the top level with this clip.

- Peter, if you want, DM me, and I can share this timeline and footage etc. whatever else if it will help get this fixed. and for what it's worth, I have been able to literally rebuild this from scratch (copying the retiming to the newly placed clips etc - the audio glitch appears to be able to be recreated in exactly the same spot.)


[Update] ///////////////////////////////////////////////////////////////
after a bit more fiddling, I'm able to recreate the glitch and make it go away and make it come back.... without voice isolation even being part of the equation.

The main audio is "Stereo", and adding an adaptive audio track(24)[or any non mono/stereo] and having a split with a transition on the bottom layer AND having an offset on the top timeline... I get the same glitch.

If the top timeline is aligned to the zero frame, the glitch appears to disappear.
If I remove the empty adaptive audio track from the time-stretch nested the glitch disappears
If I don't have the transition across the split the glitch disappears.
Caching the middle timeline (the one with the adaptive(24) audio will also make the glitch go away on the top timeline.

Adding those things back - glitch comes back.

and I have things set to not to use optimized and have everything non-cached, so the waveform has to regenerate with each change. unless specifically testing the cache.

Below is the timeline structure, hopefully clear enough:

1) glitch audio, 2) reference decomposed audio 3) audio in nested timeline, 4) Adaptive (24) empty audio - related to glitch? 5) original wav file with 1 split + cross fade, 6) another adaptive(24) empty track, 7+8) the repeat glitch 7 original, 8 repeated audio 9) no voice isolation, 10) the segment where glitch happens shown on each track.

2024-05-07_06h56_51.jpg (707.05 KiB) Viewed 795 times

If you are having audio studder occur in your nested timelines due to the use of Voice Isolation then go to the fairlight tab, select the audio clips that are studdering, right click and select "Cache Audio Effects". A check mark will appear in the contextual menu next to "Cache Audio Effects" letting you know it is active. If you ever need to turn it off, just select it again and the render cache for the audio will be removed.

That is very useful advice!

The main audio is "Stereo", and adding an adaptive audio track(24)[or any non mono/stereo] and having a split with a transition on the bottom layer AND having an offset on the top timeline... I get the same glitch.

Thanks for your testing!! Are you finding the adaptive audio track is the cause of the glitch?

I posted earlier about audio glitches happening if you don't cross fade.

On a similar topic, I've been observing another kind of glitch that happens almost every time for me - when I export an audio-only file out of a timeline, if the audio clips are enclosed in a compound clip, then they get rendered out as silence. Sometimes I get an entire file of silence...

But if I "decompose in place", or move the audio-compound-clips to another timeline and re-render, then there's no issue.

After years, i think it's safe to say that almost every version of resolve, on every system, can have this issue. The least BMD could do is warn the user in some way. This is the kind of reliability that is important.

I think it’s safe to say that, overall, Resolve’s robustness philosophy can be stated as “if there’s a way to accomplish something, be it through a workaround or a different workflow, then the issue/bug isn’t important enough to demand a fix.” This results in a great number of bugs that just never seem to get fixed.

I think this approach is ok for the user group that Resolve used to target. That of professionals who lived in the program and were paid enough to happily adjust their workflows to the platform their employer had chosen.

I think it’s a non-starter for the much larger market of casual users, YouTube community, and small shops who are nimble enough to hop to another platform.

Resolve as a suite is super attractive to this market due to its price and access to the best color grading software in existence. But becomes more trouble that most are willing to bear when the oodles of non-working paths through the software start to appear.

I didn't read the entire thread, but I know and encountered this issue. My solution was to prerender just the audio in the inner nested project. Then take that rendered file and drop onto the main timeline. Works fine then. Not ideal but worked for me.

The main audio is "Stereo", and adding an adaptive audio track(24)[or any non mono/stereo] and having a split with a transition on the bottom layer AND having an offset on the top timeline... I get the same glitch.

Thanks for your testing!! Are you finding the adaptive audio track is the cause of the glitch?

I don't think it's the root cause, but it definitely seems to exacerbate the issue. I sent BMD the entire project. I was actually able to boil it down to a repeatable glitch with no video and the one audio clip.

I wonder if people have tested for this bug in 19 hah. from the sound of it, this has been an issue since -- always and forever.