If Clips are stacked but only one is visible does it effect playback and render speed?

[Jonny34316629atjs]

I edit a lot of music videos and so I usually stack clips on video channels after syncing them with the music and then cut the best pieces of each one to build the timeline.  I often used to leave multiple videos stacked on top of one another even though only the top clip is visible in playback. A long time ago I realized playback speed is effected by this. I'm assuming it is trying to playback all the stacked clips at the same time even though only the top clip is visible. Now I always clean up my timelines to keep videos from getting left in the lower video channels, but I am curious and havent found an answer yet on whether or not this effects export speeds. If two videos are stacked in V1 and V2 but only the clip in V2 is visible, will premiere be attemping to encode both of them in an export slowing down the export speed?

[Richard M Knight]

I often find I get a red timeline when adding effects to hidden clips.

[Peru Bob]

Try deleting the Media Cache and Media Cache files:
https://community.adobe.com/t5/premiere-pro/faq-how-to-clear-your-media-cache-in-30-seconds-in-premi...

[R Neil Haugen · Accepted solution]

Yes .... think about what a sequence is. It's only metadata ... take this clip, do this with it, stored as a text file. Now play it back from that metadata of that text file.

So no matter whether the clip shows or not, the computer has to find every bit, and apply all effects to everything. 

This is why flattening a sequence prior to final export ... especially long complex sequences ... can make such a difference in export times. And success, actually.

[Tariq Salqan]

Hello,

If any processing effects are applied to the clips, they will impact export speed, regardless of whether the clips are visible or not. Effects such as color correction, transitions, filters, or any other modifications will require processing during export.

In Adobe Premiere Pro, effects are applied to individual clips regardless of their visibility in the timeline. So, even if a clip is hidden beneath other clips and not visible during playback, any effects applied to it will still be processed during export.

Therefore, it's essential to consider the overall complexity of your timeline, including the number of tracks, clips, and applied effects, as these factors can collectively affect export speed and overall performance.

[mattchristensen]

@Jonny34316629atjs Great question! At a high level the answer is no, clips on lower tracks that are fully covered by the clips on tracks above them are not affecting your playback speed. Premiere Pro does its best to ignore clips that aren't part of the final sequence composite to give you the best performance possible.

You can prove this on your own:

1. Cut a clip into a new sequence (make sure the sequence frame size is the same as the clip's)
2. Add a bunch of effects to your clip until it can no longer play back without dropping frames. Look for the effects without the Accelerated Effects icon, like Channel Blur. You should have a red line over the clip in your timeline now.
3. Cut the original clip (without effects) onto V2 above the clip with the effects

After Step 3 you should see that the red line goes away, and you can play back without dropping frames. This is because Premiere Pro is detecting that the clip on V2 is fully covering the sequence frame and so it is ignoring the clips below it when it comes time to render for playback or export.

There are of course some caveats here. If you scale down the V2 clip to 99% you'll see the timeline instantly gets the red bar back and playback is dropping frames. Once the clip on V2 isn't fully covering the sequence frame then yes the clip below it is fully processed and affecting playback. Also, keep in mind that even if the video frames are not being processed, the file on disk might still be accessed, for example if it also has audio that is used in the sequence. Premiere Pro will need to be reading the audio portion of the file to play that back, even if it's not processing video frames from the file.