BUG: Use Previews....Doesn't Use Previews.

Report · Mar 16, 2023

This workflow has been broken for a long time and I would really love to fix this one. I know this used to be on uservoice but I can't find the old bug.

Steps:

1. Set sequence preview file to "Apple ProRes 422HQ" or whatever your favorite is.

2. Render Sequence to full green.

3. Go to Export, Select an H.264 preset, check "use previews"

4. Watch as PrPro doesn't acess a single preview on disk and instead renders the whole timeline from scratch.

From my current example I have a .png sequence from blender than I've rendered to green in the timeline.

Export->H.264, use previews checked...

Look at windows resource monitor, why is premiere chewing up PNGs when it should just be referencing the preview files I JUST RENDERED.

.aecache files being acessed for no reason.

.png sequence being read. WHY.

Report · Mar 16, 2023

If you've read any of the information, "Use previews" requires that the preview and export codecs be indentical. Then it simply puts those in the file without re-encoding.

ProRes, an interframe codec, and H.264 use entirely different encoding processes. There isn't any way not to have to re-encode that process you are doing.

Neil

Report · Mar 16, 2023

@R Neil Haugen What you are describing is the "Smart Render" function which is great and useful. Thats not what "use previews" was orignally used for.

It used to "use previews" no matter the export destination or format. Yes you are "re-encoding it" but what I am hoping premiere does is use the preview files that I have spend the time rendering as the source material instead of going back down to timeline original media. In many cases this should be MUCH faster for anything with heavy effects or AE involved. Yes render and replace exists but this should also work and is much faster as you can just mash enter to get all your pro-res renders in one keystroke.

Currently my workflow is something like :

1. Export with match sequence settings to get a smart render (this actually works usually these days). We are going ProRes to ProRes.

2. Drop that file into media encoder or ffmpeg (it launches way faster) to render it out to an H.264.

I'm trying to eliminate step two as it is redundant. I should be able to use the previews within premiere to export out an H.264. That's what use previews SHOULD do (and used to do for the record) and not only be limited to smart renders.

Report · Mar 16, 2023

I don't recall it being faster to create say an H.264 export if I had previews in ProRes, which I normally do. But then, my memory could be off of course.

Perhaps @mattchristensen could give us the actual hard info?

Neil

Report · Mar 16, 2023

Its been broken for awhile now. Again, I can't find the old uservocie requests becuase that got nuked and the search function on here is less than stellar but I want to say its been borked since maybe 2018.

Report · Mar 30, 2023

I understand what you're saying, Neil, but I'm with Scrozier. This is a bug, not a feature. "Use Previews" should use the previews, period. When I render an FX-intensive timeline in ProRes, then export to an H.264 or any other format, and select "use previews", it should use the ProRes previews as its source, and NOT re-render everything from scratch. In my work, I frequently build complex, render-intensive sequences and then send lo-res .mp4 exports for iterative reviews throughout the process. The best workaround I have is to export a full-res interstitial "using sequence settings", then take that back in AME or Premiere and export it to H.264, which is cumbersome and unnecessary when all the needed ProRes previews are readily available for a direct conversion without having to do the interstitial. Adobe, please fix this, it's a huge pain.

Report · Mar 30, 2023

I'm not a codec expert by far, but from what I do know, I can't see how, in reality, your wants from previews could work. Due to the way the different format/codecs are "composed" among other things.

A "preview" has been something to get a low-quality quickly produced file for timeline playback ... that's why they can be produced quicker, because they aren't to the full specs of the sequence.

If you've needed full specs, with all the effects baked in, that's always been the render & replace option. And that, from what you've said, is what you need in the end.

Because, if you're using the preview file in an export, it must be to the full framesize and bit and color depth of the needed export. So if your export is going to be 10 bit UHD, the preview must also be 10 bit UHD.

And the file specs or construction format, must also be of the expected export. You can't just say a ProRes file becomes an H.264 by "abra-kaZAM!" ProRes is not by structure Cineform which is not DNx which is not H.264 ... they are all completely different "physical" entities.

And once that preview is made, it is a physical entity on disc. It's not just a bit of processed data. So to change from one codec to another ... requires re-rendering to that codec.

Ergo ... an eventual deliverable in ProRes422, you set your R&R to ProRes422. When you've got your effects work done, do an R&R. Now ... when you export to that ProRes422, it simply cuts together those sections of P-R422 into your export.

Fast & furious, so to speak.

But if your preview is a low-res ProRes for good playback, and your export is say H.264 ... well, they aren't the same file material in any way, shape, or form, are they? You can't simply copy a low-res ProRes and say it's now H.264.

And unless that preview is at full bit and color depth and framesize, you can't take any part of it anyway. You'd have to start from the original.

So I'm just puzzled as to how you would expect this to work. I can't see we could expect a low-res preview file of one codec suddenly becoming a full res export file of a different codec.

Neil

Report · Mar 30, 2023

Previews are neither lower nor higher quality by defintion: they are the quality and resolution and codec which you choose for them to be in the Sequence settings panel. And I am in fact pretty well-versed with various codecs, bit depth and resolution settings, inter-frame vs intra-frame compresion, etc. But if I do choose a lower quality, resolution, compressed or lossy codec, etc in my previews, then that's my decision to make, and I'd like Premiere to use those previews, whatever they are, on export, if I have checked "use previews". If I want it to re-render everything from scratch directly into the export codec, which I freely concede is the most lossless and highest fidelty way to export a final master, then I'll uncheck "use previews". Right now, "use previews" is a meaningless button, b/c it doesn't force the export dialogue to actually use the previews. This is not a problem I had back in the Final Cut Pro 7 days, and I could be mistaken but I think it didn't used to be a problem with Premiere either.

Report · Mar 30, 2023

Terminology can vary by program. And therefore use.

"General" previews in Premiere ... since I started using it back with CS6 in 2013 ... have been used as a quickie playback tool. Never intended for export use.

The entire "use previews" process in Premiere's export process, as spelled out in their "Smart Preview" documentation for Smart Previews, has been consitent all these years. To use the previews in export, the previews must be both using an interframe codec and that codec must the the precise one to be used in the export.

What FCP did or didn't do is nifty to know. And suggesting alternative practices in Premiere is always a great thing to do.

I'm just noting that what happens now is always a Premiere has worked. And ... that I can't see how setting any preview to a codec different in any respect to the final one is supposed to be useful in the export.

Neil

Report · Mar 30, 2023

Hi! @Ryan Fritzsche. Your wife taught a class back at my college back in the day say hi to G for me!

I'm going to write a lot here for what is actually just a very simple bug but here we go:

@R Neil Haugen regardless of how it works currently or how the language in the documentation, I've been using this peice of software since before the great migration from FCP7 in 2010 and I can confirm that "use previews" button used to work as described by myself and @Ryan Fritzsche. At some point in the last five-six years the feature was nuked and it was never explained why you could no longer use your preview files as an export source.

Basically preview files are just timeline proxy files that live with the seqeunce. They used to default to a low quality codec (mpeg I-frame, not something you would want to generate a final output with) but you have almost always been able to select a higher quality intermediate codec. These intermediate codecs are more than good enough to generate an output (hence smart preview rendering for final output). As Ryan mentioned, in many workflows, you don't want to upload these big files for review and its quicker and easier to just use the preview files already there to generate an output. As menitoned the current workflow is a two-step affair (smart render -> re-render to H.264) when it should really be as simple as checking the "use preview box"

This would be super beneficial to editors working on commecials (such as myself) who may have to delivery many cuts in a single day (think all the aspect ratios and sizes we have to deliver to now) It would save LOADS of time in a day on either re-rendering effects time or roundtripping time, not to mention just making it easier to do what I want.

Current (broken) workflow.

1. Go into each output sequence and select all effects clip and make sure you have "rendered and replaced" all the clips that are red. Repeat this many times during your conform day. This is going to take you a lot of time and a lot of QC to make sure everything is rendered properly to right aspect ratios, and potentially making RnR presets.

1b. Don't bother with RnR as this is a tedious process and just live with the slow render times. This bites you in the a** as any QC issues will now compound this and cause you to spend even more render time rendering the effects a second, third, fourth time.

2. Export to all your web deliverables knowing that everything has been "Baked" in. Don't bother with "use preveiws" as it doesn't do what you think it does.

3. You are late for dinner.

Old/Ideal workflow:

1. Setup every sequence as you go along to use something suitably high quality (ProRes422HQ or ProRes4444) with all max settings ticked

2. Select all sequences in bin and select sequence->Render in to out. Premerie will render all sequences to disk.

3. All effects are rendered with one keystroke/shortcut.

4. Go get some coffee.

5. Export everything with "Use previews" and get home in time for dinner as everything exports very fast. Any QC that doesn't touch your FX work is a quick turnaround.

5B. Export everything to media encoder with "use previews" checked and pray to the media encoder gods that it actually works and doesn't make some weird asinie mistake like out of sync audio or borked AE fies.

Report · Mar 30, 2023

Also FCP7s preview files were more robust! The program was able to render partial preview files on the fly and wouldn't throw away an entire render if you changed just one part of a longer clip. Also the thumbnail cache! What a concept! I'm still waiting for PrPro to reach feature parity with FCP7 10 years on.

Report · Mar 30, 2023

I'll have to take your word for it, until I can get some time on this in the shop. Last time I used the process was sometime in December.

And at that time, an export using previews of the same codec worked. I had my previews set to ProRes 422, export also to that, and it was a very fast process.

If that no longer works it would be a mess.

@Kevin-Monahan can you test this on Macs?

Neil

Report · Mar 30, 2023

Hi scrozier,

Using Previews really only works in a smart rendering workflow. Previews are not used in any other kind of export where codecs are mixed (H.264 and ProRes, for example). Preview files must match the export codec, and that it must be capable of smart rendering. H.264 is not one of those codecs. Sorry if this workflow is unclear. If you can find anything in the documentation that says otherwise, please point me to it and I will make sure a correction is made.

If I recall, this was the same workflow that Final Cut Pro used to give us.

Thanks,
Kevin

Report · Mar 30, 2023

@scrozier Hey man! Gillian was stoked to hear from you - small world!

@Kevin-Monahan We understand that this is how it works. We are saying we think this is silly. Maybe that makes this a feature request? When I set my previews to ProRes, for example, a series of ProRes preview .movs are created in my previews folder. Then, when I hit play in my sequence, Premiere strings (or "edits", if you will) them together in sequence, in real-time. When I go to export, why can't I ask Premiere to just do that same process directly into the encoding engine or process? It's doing it when I hit play in the timeline.

Here's why this matters: on any given project, whehter it's a :30 spot, a 3 min corporate video, a short film, a feature film or anything else, the vast, vast majority of the exports I do will be lo-res, lo-quality screeners that I'm sending to clients/directors/producers/etc to review the creative edit. I'll only be mastering at full or maximum quality and resolution a couple times - (ideally once, but someone always has to mess around after pic lock). So, requiring the export mechanism to re-create preview files (that would have been absolutely fine for my needs, even if they are low quality, which i somethign I can and control on purpose) every time I do an export to a codec such as H.264 is time-consuming, and creates multiple issues.

I understand wanting to make sure exports look their best but 19 out of 20 exports, I don't care about it being 10-bit 8k 4444 or whatever. I just need to quickly get a low or medium quality .mp4 out, and besides... if I want it to work from the highest quality and resolution settings, then I'll set my preview settings to that.

Examples: Today I'm working on 90s piece for a corporate client that involves a tremendous amount of 4k & 6k Sony and RED footage, with lots of color correction and other FX. It take about 5 mins to render the sequence on my Mac Pro. The sequence is set to 1080p ProRes. If I export it directly to H.264, at 640x360, it takes about... 5-6 minutes. If I export it as "use sequence settings", it takes about 1 minute to generate a 1080p ProRes .mov. If I take that 1080p ProRes .mov into Media Encoder, it takes about 45 seconds to produce the 640x360 H.264. That is my workaround. But there is no technical reason I can see why the middle man couldn't be cut out there; that is, why can't I export, "using previews" directly into the 640x360 H.264 in about 45 seconds from Premiere directly?

Now I get why that may sound like crying over spilled milk, becuase what's wrong with the extra step if it saves 4 minutes, even if I might prefer to save 5 minutes. But... when I am cutting feature docs, with many mixed formats of raw footage, I frequentkly export 1 to 2 hour sequences. I expect that to take a while of course, but here's the real Sophie's choice. If I export it directly into H.264, it takes hours. If I export it "using sequence settings" then it's obviously much faster, but it still takes a lot longer than 1 minute to export an hour of ProRes. Plus I end up with a large interstitial file, which I have to have disk space for, and there's the tax of disk write speed - now Premiere has to not only read all those preview files, but also to write them somewhere else, and that little bit of extra disk writing starts to add up to a big inefficiency, especially when all the ProRes previews have already been written. So... now instead of being able to hit export and have an .mp4 by the time I get back from lunch, I can either hit export and have an .mp4 hours from now, or I can export the ProRes, which will be done when i get back from lunch, but then I have to run that thru AME or Premiere to make the H.264, and wait on that process. So in either case, extra time or extra steps are involved in what should be a one-click process.

Premiere doesn't have a problem accessing those preview files in real time while I'm editing, so why should it have trouble accessing and stitching them together accurately on export?

I get that inter-frame codeces create problems of call kinds and aren't a great previews format, but that's not a workflow I ever use. I always use ProRes or DNxHD or some other intra-frame codec for previews. Conversely, unless I'm delivering a final master, I'm never going to post a 100 GB ProRes file for review on Frame - it's monstrous overkill and would take forever to upload. I'm never going to use an inter-frame compression such as H.264 for previews, b/c that would tax performance inordinantly. So whether you agree with me that our descriptoin of this whole situation is a bug or a feature request, surely I hope you can see why my workflow of cutting with ProRes previews, and exporting to H.264 is common, and the efficiency of it ought to be taken into consideration.

Ok, so there's my case.

But here's one more thing: It seems that under the current, intended functionality you described, the "use previews" checkbox is a meaningless setting in the export dialogue, unless the export format/codec matches the previews. If that's the case, then why is it not grayed out when I'm exporting with a format or codec that differs from the sequence previews setting? The "use proxies" checkmark always does what it says, no matter what codec i'm exporting from or to, and it's right next to the "use previews" checkmark, so I would expect them to behave in similar fashion. If I can select a checkbox, then it ought to do what it says; otherwise it shouldn't be grayed or invisible.

Currently, the export UI is not correlating with the current or intended functionality, and if nothing else, that's confusing, and promises an outcome that's not actually being offered. Surely I hope we can agree that at very least, that could be considered a "bug".

Thx for humoring us, Kevin - I know you guys hear a lot of belly-aching from editors on here, and I can imagine it gets tiring. But this is an issue that consistely frustrates me and slows down my workflows, and I would really love to see a "use previews" option for situations where I'm NOT exporting "using sequence settings".

Report · Mar 30, 2023

Kevin,

Appreciate you taking a look at this. I don't think its my best use of time to dig through Premiere's manual to try and prove something here. Looking for this feature to work and not necesarily a webite update.

Just on a quick google I did come across this: https://helpx.adobe.com/premiere-pro/using/bestpractices-export.html

Most of these suggestions are thrown out the window because use previews doesn't work as described.

"Using Previews to speed up export

Premiere Pro’s default Previews are optimized for playback, not image quality. If you select Use Previews in the Export mode, Premiere Pro will apply the Preview render files for your export.[false or does not mention that you need to match codec] That may give you a speed boost, but you will be re-compressing an already compressed file, which is not ideal for quality.[Premerie straight up refuses to re-compress files using previews at this point] You can get the best of both worlds (editing performance and optimal export quality) by choosing a high-quality codec for your Previews. [false]

Again the very name "use previews" alludes to a time where it actually used previews to export, not its current funcitonality. Agree with @Ryan Fritzsche that this is at the very least, a poorly named feature, but more likely a bug or feature that was turned off.

At the end of the day this SHOULD be a feature, (and unless my memory is just horrendously damaged), was a feature that used to work. Just admit its a bug I don't know why there is so much runaround in this community.

Report · Mar 30, 2023

https://www.adobepress.com/articles/article.asp?p=1661113&seqNum=5

Here is an older article back from the CS4-CS5 days (about when I started using PrPro) when the feature was still intact.

Report · Mar 30, 2023

I'm trying to remember when I first started noticing this issue - that is, my export times started to get longer - and I can't recall exactly but I think it was with CC 2020 or maybe CC 2021? But I'm 100% certain it used to work the way that @scrozier and I are describing. I've been using Premiere as my primary NLE since 2014.

Report · Mar 30, 2023

Sorry guys, as you may know, I'm not a dev, and I'm not on the Premiere Pro product team at all, so I have no say in the matter as to why the feature works the way it does in the past or present. If you want Using Previews to work differently, you are free to create a feature request.

I agree that the topic is confusing and the documentation you pointed out is not helpful, so I'll work with that team.

Thanks,
Kevin

Report · Mar 30, 2023

"Use Previews" functions exactly as described.

If "Use Previews" is enabled, Premiere Pro uses the files in the corresponding dot PVR folder during export.

If "Use Previews" is disabled, Premiere Pro does not use the files in the corresponding dot PVR folder during export.

If the Previews have been rendered to an appropriate resolution for the export settings, it should always be worth enabling this option.

As far as H264 goes, no NLE uses it as an optimized COEC for editing because it's not an optimized CODEC for editing.

Report · Mar 30, 2023

@scrozier

If quality is a concern, H264 should be avoided.

Use a CODEC with a deep peak signal noise ratio (PSNR).

Report · Mar 30, 2023

@Kevin-Monahan

I am aware you are not a developer. I filed this under "Bug" since it used to work a certain way and now works in another way I don't expect. Should I file this under feature request instead?

Report · Mar 30, 2023

@Warren Heaton It doesn't. When you tick the check previews box it doesn't access the .prv folder at all. See my screenshots a the top of the post, its going back to the .png source of a part of the sequence I already rendered. Its been broken for a number of years.

Report · Mar 31, 2023

ditto.

Report · Mar 31, 2023

@Kevin-Monahan When I click the link to "report a bug or request a feature", I get sent to this forum. Can you post a link to where I would submit this as a feature request?

Further, with all respect to the fact that you're not a dev, isn't this the place to surface these kinds of issues to Adobe? Are you saying that people in your position are not empowered to escalate this issue to the dev team? It is a fact, corroborated by Adobe's manuals, that this used to work the way we're describing, and it has stopped. I consider that a bug, but if it's a "new feature" at this point, then fine: where do I submit that request, if not here?

Report · Mar 31, 2023

At the upper right of this forum, there's the "Post to Community" blue icon. Click it.

Then you get a text box, and below it, 'radio' circles to click as to whether your post is a discussion, idea, or bug.

Neil

Report · Mar 31, 2023

Thx @R Neil Haugen - I will re-post this issue as an "Idea" there. I'm taking note that this very discussion is already flagged as a "Bug" and not a "discussion".

I'm inferring here that @Kevin-Monahan doesn't feel this qualifies as a bug, b/c the current functionality fits the current expectation at Adobe. But to my point articulated above, if I accept that framing of the issue, there is still a logical incongruity between the interface and that the functionality; I don't see how we don't have some kind of bug here, of some stripe - either previews should be used on alternative codec exports when the "use previews" box is checked, or the "use previews" checkbox should gray out / go away / un-check itself on alternative codec exports. Surely we can agree that the interface saying something is happening that is not actually happening is a bug of some kind, right?

Adobe Community

BUG: Use Previews....Doesn't Use Previews.

"Using Previews to speed up export