Nested clips affecting editing/rendering performance

Hello Neil,

Doing a render & replace for any significant effects means your final exports will of course be a ton faster ... as the processing work for the effect has already been done, it's mostly just an encoding process then. One other reason why R&R can be actually quite a useful process.

Yes, I'm sure it can be useful for very heavy effects, but I'm simply using nested clips with a simple cross dissolve transition.

Here is the timeline for one of the projects I'm working on:

The clips that require the patch (to hide the stand) are all on V2 - it would be far too much work to R&R all of those clips at this stage.  Instead, I'll make a copy of the master sequence and simply remove any clips on V1 whenever there is a clip on V2 at the same time.  However, I shouldn't really have to do this - I believe this additional rendering overhead when using nested clips is a bug in Premiere.

By the way, is there a way to formally report a bug/oddity to Adobe for investigation?

Thank you for the suggestion, Neil.

Yes, that would work, however I'd rather avoid that workaround if I can.

It would be preferably to understand why the nested sequences cause the performance to drop.  Well, I think I do understand what is causing the issue, I just don't under why it should occur.

I guess what I may end-up doing is making a copy of the 40 min. master project timeline, and just deleting any clips that occur below a nested clip.  If my theory is correct, this should result in a signifiant performance improvement.  Currently, the full 40 min timeline exports in around 90 minutes.

Thanks again for your reply.

Hello John, thank you for your reply.

Adobe's version of PP for M1 is very new. It could be related to that.

Yes, that's true.  However, I just tried the same test using Premiere and Media Encoder running under Rosetta (i.e. the Intel version) and the performance is largely the same.

However, I believe I may have found the cause of this issue.

When exporting a timeline with just the nested clip, the performance is the same as if exported a timeline with the clip track and patch track.  However, if there are additional video tracks below the nested clip, export performance suddenly tanks.  It's as if Premiere is having to render both the contents of the nested clip *and* the clip(s) below - even though they are covered by the nested clip, and should therefore be ignored by Premiere - as explained by Ann Bens here.

Take a look at these export times, taken from AMEEncodingLog.txt:

1. clip.mp4 [the original 60s 4k footage] - Encoding Time: 00:00:31

2. clip-patched.mp4 [same as 1, but with PSD patch layer added] - Encoding Time: 00:00:34

3. clip-patched-nested.mp4 [2 convered to a nested sequence] - Encoding Time: 00:00:33

4. clip-patched-footagebelow.mp4 [2 with another video track underneath] Encoding Time: 00:00:34

5. clip-patched-footagebelow-nested.mp4 [3 with another video track underneath] - Encoding Time: 00:01:16

Here is a screeshot of the simple test timeline, for reference:

Of course, nesting clips replaces the original clips with a single nested clip, so keeping the original clips as in this screenshot is a little unrealistic.  However, the point is that when there is another clip below the nested clip, the performance deteriorates considerably, even though the nested clip opacity is 100%, so Premiere should simply disregard any clips below.

I'm happy to share this test projet and media, if anyone would like to check it out for themselves.