Scrubbing Lag.

Explorer ,
Nov 08, 2017

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When Scrubbing on the timeline or any of the monitors, the higher the resolution the "choppier" it gets to scrub.

However, some higher resolution formats (i.e 4k Arri mov) perform much better that lower resolution formats (i.e 1080 Canon mp4)

Of course scrubbing is silky smooth when the timeline is rendered. Changing the resolution on the program monitor from full to 1/4 does not affect how smooth is it to scrub, only the resolution when scrubbing. Scrubbing also is smooth if a specific video have been scrubbed/played before.

(i.e if I scrub a 4k video freshly imported to the timeline, it scrubs with an awful lag. If I play the video from beginning to end, and then try to scrub it, it scrubs smooth)

Files natively compressed with Prores don't have any issue. The issue here is mainly with h.264

So in order to achieve smooth scrubbing under any circumstance, and to avoid people who just spend time on forums because they are bored, Please answer the following questions if you have a solid answer.

1) When ONLY playing a video in premiere, what happens in the background. we know that importing, creates peak files and conformed files. what does playback or scrubbing do?

2) Is there a way to force whatever happens in the background during playback without actually playing?

3) Nothing, in any setting around premiere affects the smoothness of playback or scrubbing. Am I missing something?

4) File format/compression seems to be a major factor regardless of the resolution

iMac (Retina 5K, 27-inch, 2017)

4.2 GHz i7

64gb 2400 MHz

Radeon Pro 580 8gb

Adobe Community Professional
Correct answer by R Neil Haugen | Adobe Community Professional

It's pure physics or math if you prefer.

The files you're having trouble with are long-GOP, which is a codec type that works great with a specially designed chip in the camera to reduce a LOT of data to something recordable on the card ... fast. It is NOT designed to edit worth a crap.

There's only a "real" complete (though heavily compressed) " I " frame every 9-30 "recorded" frames. In-between are "p" and "b" frames, which aren't frames at all. They're a data-set of only the pixels that have or will change from the last I frame or the next one ... or both. The computer has to de-encode an I frame, pass along, store to RAM, call up the next p/b frame, recall the I frame from RAM, compute that frame ... pass it along, store to RAM, call up the next p/b dataset, recall ... rinse & repeat.

FAR more work than simply de-encoding complete frames, even "large" many-K frames.

ProRes, Cineform, and DNxHD/R are codecs designed for editing. Every frame is a complete frame and simply compressed in a format designed for fast de-encoding.

So there isn't something weird going on in the program, and your questions there don't really matter at all.

It's the codec you're working with. Which is why you may very well need proxies to get smooth playback when dealing with H.264 1080p, but work some 6k ProRes or DNxHR without trouble.

And when making proxies, do NOT use the included H.264 preset, I've no clue why anyone would want that. Use the Cineform ones ... they will playback smoothly and fast.

Neil

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Scrubbing Lag.

Explorer ,
Nov 08, 2017

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When Scrubbing on the timeline or any of the monitors, the higher the resolution the "choppier" it gets to scrub.

However, some higher resolution formats (i.e 4k Arri mov) perform much better that lower resolution formats (i.e 1080 Canon mp4)

Of course scrubbing is silky smooth when the timeline is rendered. Changing the resolution on the program monitor from full to 1/4 does not affect how smooth is it to scrub, only the resolution when scrubbing. Scrubbing also is smooth if a specific video have been scrubbed/played before.

(i.e if I scrub a 4k video freshly imported to the timeline, it scrubs with an awful lag. If I play the video from beginning to end, and then try to scrub it, it scrubs smooth)

Files natively compressed with Prores don't have any issue. The issue here is mainly with h.264

So in order to achieve smooth scrubbing under any circumstance, and to avoid people who just spend time on forums because they are bored, Please answer the following questions if you have a solid answer.

1) When ONLY playing a video in premiere, what happens in the background. we know that importing, creates peak files and conformed files. what does playback or scrubbing do?

2) Is there a way to force whatever happens in the background during playback without actually playing?

3) Nothing, in any setting around premiere affects the smoothness of playback or scrubbing. Am I missing something?

4) File format/compression seems to be a major factor regardless of the resolution

iMac (Retina 5K, 27-inch, 2017)

4.2 GHz i7

64gb 2400 MHz

Radeon Pro 580 8gb

Adobe Community Professional
Correct answer by R Neil Haugen | Adobe Community Professional

It's pure physics or math if you prefer.

The files you're having trouble with are long-GOP, which is a codec type that works great with a specially designed chip in the camera to reduce a LOT of data to something recordable on the card ... fast. It is NOT designed to edit worth a crap.

There's only a "real" complete (though heavily compressed) " I " frame every 9-30 "recorded" frames. In-between are "p" and "b" frames, which aren't frames at all. They're a data-set of only the pixels that have or will change from the last I frame or the next one ... or both. The computer has to de-encode an I frame, pass along, store to RAM, call up the next p/b frame, recall the I frame from RAM, compute that frame ... pass it along, store to RAM, call up the next p/b dataset, recall ... rinse & repeat.

FAR more work than simply de-encoding complete frames, even "large" many-K frames.

ProRes, Cineform, and DNxHD/R are codecs designed for editing. Every frame is a complete frame and simply compressed in a format designed for fast de-encoding.

So there isn't something weird going on in the program, and your questions there don't really matter at all.

It's the codec you're working with. Which is why you may very well need proxies to get smooth playback when dealing with H.264 1080p, but work some 6k ProRes or DNxHR without trouble.

And when making proxies, do NOT use the included H.264 preset, I've no clue why anyone would want that. Use the Cineform ones ... they will playback smoothly and fast.

Neil

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Nov 08, 2017 0
Adobe Community Professional ,
Nov 08, 2017

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It's pure physics or math if you prefer.

The files you're having trouble with are long-GOP, which is a codec type that works great with a specially designed chip in the camera to reduce a LOT of data to something recordable on the card ... fast. It is NOT designed to edit worth a crap.

There's only a "real" complete (though heavily compressed) " I " frame every 9-30 "recorded" frames. In-between are "p" and "b" frames, which aren't frames at all. They're a data-set of only the pixels that have or will change from the last I frame or the next one ... or both. The computer has to de-encode an I frame, pass along, store to RAM, call up the next p/b frame, recall the I frame from RAM, compute that frame ... pass it along, store to RAM, call up the next p/b dataset, recall ... rinse & repeat.

FAR more work than simply de-encoding complete frames, even "large" many-K frames.

ProRes, Cineform, and DNxHD/R are codecs designed for editing. Every frame is a complete frame and simply compressed in a format designed for fast de-encoding.

So there isn't something weird going on in the program, and your questions there don't really matter at all.

It's the codec you're working with. Which is why you may very well need proxies to get smooth playback when dealing with H.264 1080p, but work some 6k ProRes or DNxHR without trouble.

And when making proxies, do NOT use the included H.264 preset, I've no clue why anyone would want that. Use the Cineform ones ... they will playback smoothly and fast.

Neil

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Explorer ,
Nov 08, 2017

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Gotcha! I know that h.264 codec is the culprit. Kinda suspected no settings will improve that.

However, What I noticed is that when the file is played from beginning to end, scrubbing of whatever was previously played becomes much smoother. so let's call it the de-encoding process. Premiere needs to de-encode any file (or frame) once, when it is played. More specifically, whenever a frame is played or shown on the program or source monitor, it is de-encoded once and for all and it literally takes a fraction of a second. but trying to de-encode several frames at once through scrubbing will cause the scrubbing to lag.

I know there is not anything weird, I was looking to find out the technical process which you explained perfectly. and which only seems to happen when a frame is processed through premiere by playing or placing the playhead on it. Is there a way to force this process? Rendering the timeline is a perfect solution, but keeps us stuck if need to scrub in the source monitor.

Speaking of which, I Proxie using H.264 for the sake of the file size. Why? simply because my proxies are located on a mobile drive that I often find myself needing to use outside the office. I do have 3-4 tb projects, so i dump my proxies (low res, low bit rate) on a portable drive that I take with me home during the weekend to edit offline. makes sense?

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Adobe Community Professional ,
Nov 08, 2017

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While there's enough RAM or maybe a buffer file with that clip de-encoded, you may get better playback ... go down the line a bit and more gets worked, and voila ... now go back, and it's needing to re-de-encode. So that's dependent on your hardware.

Yea, using H.264 proxies because you don't have much space makes initial sense ... but doesn't really allow you to start working bigger projects faster. At some point, you just need more drive space. Part of the editing life. Amazing how much drive space an editor goes through in a hurry.

Neil

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Explorer ,
Nov 08, 2017

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iMac (Retina 5K, 27-inch, 2017)

4.2 GHz i7

64gb 2400 MHz

Radeon Pro 580 8gb

This is my hardware, also my storage set-up is optimized for editing which kinda explains why i'm upset. This should chew it up seamlessly.

Just tested something, When I close the project I lose the de-encode process. So I believe it's processed and temporarily stored on the RAM and gets reset when the project is closed.

Just a question anout proxies, you mean to say that h.264 takes longer to create than cineform or prores?

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Adobe Community Professional ,
Nov 08, 2017

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By it's nature, H.264 takes more CPU to de-encode every time you play it. That's why it seems in most cases an odd choice for proxy use, which is all about playback. Cineform, ProRes, & DNxHR/R proxies take a bit more space but play back so much better.

Bill Gehrke, the real expert on real-world computer parts & PrPro use has found that apparently in the 2017 release (11.x build series) something was altered in PrPro such that it works notably better with '3rd generation' SSD drives than even large fast striped-array RAID-0 setups, as used to be the case. He now gets great performance on his laptop with I think a Samsung Evo 950 or similar for system/programs/cache files, and an m.2 Samsung drive for his projects & media. If you go over to the Hardware forum, and look around, you'll see his posts there on the subject.

And just a comment ... I know a number of colorists, ones who go around teaching colorist work. Some of the most Mac-centric people on the planet. But since it's been five years since Apple produced their last big-Mac mobo, and other things ... they're having to abandon their beloved Macs for ... gasp ... PC's. Built to well outperform their incredibly costly Mac rigs in Resolve, PrPro (yea they occasionally have to use it), whatever. For less cost.

I've had a hoot reading articles about "All those things we love about our Macs, the usability apps and all ... they really do exist for PC's also!" Yea, ya think? lol

Hardware is bits & pieces. And spendy may or may not get you anything. Quadro cards, for instance ... one I know had twin Quadros in his Mac, initially moved those to his new PC. He needed among other things fast screen re-draw and 10-bit output for all his monitors and outboard devices. Got a 1080 for his home machine, was amazed. Took it out and to work, plopped it in place of his $12,000 or so worth of Quadro cards ... everything worked, he had full 10-bit out to his Flanders and his external scope-box outfit, and his redraws in Resolve were faster.

Needless to say, he's preaching to his peers now that Quadro's ain't necessarily useful other than as a money-maker for Nvidia.

Hardware is hardware. Operating systems come & go. The work just needs doing.

Neil

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New Here ,
Nov 16, 2020

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You certainly have a point. But what I don't understand is, MacBook Pros that were released after 2018 comes with the T2 chip that can encode and decode H.264. But I'm having the issue with H.264 in a Mov container. I should not be having this issue. ProRes is a native Apple codec and it'll be fast anyway. But H.264 should be smooth on Macs that carry a T2 chip. I can see that the T2 chip is working because the machine doesn't heat up much or fans don't go into full blast when working on full blast when I work with H.264 files. But the Scrubbing Lag is frustrating. Not allowing me to have a smooth flow of work.

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New Here ,
Nov 16, 2020

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A tutorial on how to fix laggy playback on videos while editing your timeline in Premiere Pro CC. This works great if you are having performance issues with...

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