31 Replies Latest reply on Jul 14, 2012 7:32 AM by able123

    Preview file rendering halfs the resolution

    lastala Level 1

      Hi,

       

      I have a problem with Premiere Pro preview files: their horizontal resolution is only half of the set resolution. This is seen in the Program window both when playing back and stopped (playback resolution and paused resolution are both Full). If the clip hasn't been rendered for preview, the resolution is full. Just when rendering the preview, the horizontal resolution gets half. I'm using Apple ProRes as te preview codec (I do not want to use MPEG for its bad quality). Why is this happening? I need to have the full resolution for playback with ProRes codec, but how can I get the full resolution? Please, help!

       

      My Sequence Settings are (for instance):

       

      Settings

      Editing Mode: Custom

      Timebase: 25.00 frames/second

       

      Video

      Frame Size: 1920 x 1080 16:9

      Pixel Aspect Ratio: Square Pixels (1.0)

      Fields: No Fields (Progressive Scan)

      Display Format: 25fps Timecode

       

      Audio

      Sample Rate 48000 Hz

      Display Format: Audio Samples

       

      Video Previews

      Preview File Format: QuickTime (Desktop) / (GammaCorrection: Automatic)

      Codec: Apple ProRes 422

      Width: 1920

      Height: 1080

      Maximum Bit Depth (not checked)  Maximum Render Quality (not checked)

        • 1. Re: Preview file rendering halfs the resolution
          shooternz Level 6

          What is your source footage?

          • 2. Re: Preview file rendering halfs the resolution
            lastala Level 1

            It is not depending on the source footage. I have, for instance, footage of Apple ProRes 422 (1920 x 1080) and RED Code files (R3D, 4kHD). But as I said, it produces the same thing with different codecs: when rendering preview files (ProRes or R3D) the horizontal resolution drops down to 960 (instead of 1920), that is image pixels seem to have 2:1 pixel aspect ratio (image aspect ratio not changed).

            • 3. Re: Preview file rendering halfs the resolution
              Jim_Simon Level 8

              I'm curious how you've determined that the resolution is halved?

              • 4. Re: Preview file rendering halfs the resolution
                lastala Level 1

                Well yes, I do not know if the real resolution is halved, that's true. However, as I described before, the preview rendering seems to, at least, "replace" every second pixel with its adjacent value, i.e. the pixels seem to have 2:1 aspect ratio, even the original image has 1:1 pixel aspect ratio. So, half of the information is dropped out, at least you can clearly see that visually.

                • 5. Re: Preview file rendering halfs the resolution
                  Jim_Simon Level 8

                  Maybe I'm still missing it.

                   

                  Are you saying the previews are stretched out, or squished in some way?

                  • 6. Re: Preview file rendering halfs the resolution
                    lastala Level 1

                    No, the previews are not stretched out. As I said before, the image aspect ratio is unchanged (1920 x 1080, 16:9), but the pixel aspect ratio is changed (1:1 => 2:1). So, the horizontal (visual if you like) resolution of the image is halved.

                    • 7. Re: Preview file rendering halfs the resolution
                      Harm Millaard Level 7

                      Are your previews set to full?

                      • 8. Re: Preview file rendering halfs the resolution
                        lastala Level 1

                        As I told before, playback resolution and paused resolution are both full. You can find also my Sequence settings above.

                         

                        Here's an example image:

                        preview example.jpg

                        • 9. Re: Preview file rendering halfs the resolution
                          Jim_Simon Level 8

                          the pixel aspect ratio is changed (1:1 => 2:1).

                           

                          Here's the thing.  If the PAR were actually changed, and it's unlikely it was, then the image would appear distorted.

                           

                          It's likely something else is going on here.

                           

                          You listed the sequence settings, but what are the source media specs?

                          • 10. Re: Preview file rendering halfs the resolution
                            lastala Level 1

                            Here's the thing. I have already listed the source media specs, and I have told that (at least with my preview settings) this phenomemnon is not dependent of the source specs - I have said this previously in this very same discussion.

                             

                            I don't care if the pixel aspect ratio or something else is changed, that is not the point. The point here is that the image quality gets much worse when rendering the preview! Even if the preview setting is set to full resolution. Please, look at the example image that I posted earlier. If you look carefully, you will see the pixels being 2:1 or at least two adjacent pixels are always the same, i.e. information of every second pixel is left out, the image looks more "blurred", the image has more of stepped edge.

                            • 11. Re: Preview file rendering halfs the resolution
                              Jim_Simon Level 8
                              I don't care if the pixel aspect ratio or something else is changed, that is not the point.

                               

                              It kind of is.  It's much easier to resolve an issue if you know what exactly is happening.  And in this case, it's not likely the PAR that's changing.  You can verify this by going into a folder and opening up one of the actual preview files and checking it with software that can read the data, like MediaInfo or Gspot or even VLC.

                               

                              The goal here is to try and determine exactly what is happening, so that steps to stop it from happening can be taken.

                              • 12. Re: Preview file rendering halfs the resolution
                                lastala Level 1

                                VLC says about the preview file:

                                 

                                Type: video

                                Codec: Apple ProRes 422 (apcn)

                                Language: English

                                Resolution: 1920x1080

                                Display resolution: 1920x1080

                                Frame rate: 25

                                 

                                Everything just as it should be.

                                • 13. Re: Preview file rendering halfs the resolution
                                  Jim_Simon Level 8

                                  OK.  So there's nothing wrong with the actual file itself.

                                   

                                  Next, do you see the issue only when the preview is played inside of PP, or are you also seeing it when you export?

                                  • 14. Re: Preview file rendering halfs the resolution
                                    Level 4

                                    looks like an anti aliasing problem to me ??

                                     

                                    ========

                                    Video Previews

                                    Preview File Format: QuickTime (Desktop) / (GammaCorrection: Automatic)

                                    Codec: Apple ProRes 422

                                    Width: 1920

                                    Height: 1080

                                    Maximum Bit Depth (not checked)  Maximum Render Quality (not checked)

                                    ========

                                    what happens if you check both the max bit depth and max render quality ??

                                     

                                    found this info which might apply in some way to your problem...maybe you could try the animation codec instead ?? then export as you like.. you'd just be using the animation for the previews...

                                     

                                    http://forums.creativecow.net/thread/2/1007725

                                     

                                    see info re: the 4.2.2 biz with color and aliasing

                                    • 15. Re: Preview file rendering halfs the resolution
                                      lastala Level 1

                                      Able123, checking Maximum Bit Depth or Maximum Render Quality does not change the issue. And using animation would be hard drive space consuming. I would prefer to keep using ProRes, a big part of files are anyway in ProRes (exported from FCP), and the problematic phenomenon does not occur with them.

                                       

                                      Jim, yes, I do see the problem with exported files, too. I imported both the preview file and the exported file to After Effects, and I can't see the problem there. The very same files show no problem in AE. So, the problem seems to be in Premier Pro itself, how it interprets the files it has generated itself (no problems with ProRes exported from FCP).

                                      • 16. Re: Preview file rendering halfs the resolution
                                        Jim_Simon Level 8

                                        If After Effects is not showing any issue with either file, then there likely is no issue at all with the actual files, only with how PP displays them.  Possibly related to the graphics driver.

                                         

                                        As the monitors inside of PP are for viewing content only, and should never be used for judging quality, this issue can be safely ignored.

                                        • 17. Re: Preview file rendering halfs the resolution
                                          lastala Level 1

                                          Thank you for your comment, Jim. I understand that the exported files are OK. However, my point is about the workflow. I really want to be able to show full resolution (Apple ProRes 1920x1080) preview files on a HD monitor. This is important for my workflow. And it is very annoying to suddenly not being able to do so.

                                           

                                          I would expect that Premiere Pro would be able to handle properly the files it produces itself. I would also expect that there would be a solution for this problem I have now. Can you help with that?

                                          • 18. Re: Preview file rendering halfs the resolution
                                            Jim_Simon Level 8

                                            preview files on a HD monitor.

                                             

                                            You're saying this issue crops up in external monitoring as well?  You have something like an AJA, Blackmagic or Matrox hooked up?

                                            • 19. Re: Preview file rendering halfs the resolution
                                              lastala Level 1

                                              Yes, it happens also in an external monitor as well. I have a MacBookPro OSX10.6.8 and a 23" Cinema Display. The described problem occurs both on the laptop screen and the external Cinema Display - and it happens also on the laptop screen even when the Cinema Display is not hooked on.

                                               

                                              Remember I told that ProRes (1920x1080) files exported from Final Cut Pro play flawlessly in Premiere Pro (CS6). So, the problem concerns only PP preview and files exported from PP. So, PP is misinterpretting only files that has been produced by itself.

                                              • 20. Re: Preview file rendering halfs the resolution
                                                Jim_Simon Level 8

                                                That is strange.

                                                 

                                                As a test, change the preview file codec to something other than ProRes.

                                                 

                                                Also, how is the Cinema Display hooked up?

                                                • 21. Re: Preview file rendering halfs the resolution
                                                  lastala Level 1

                                                  This is strange, yes.

                                                   

                                                  I made a test with different preview file codecs, and noticed that the problem occurs with Apple ProRes 422, Apple ProRes 422 (HQ), Apple ProRes 422 (Proxy) and Apple ProRes 422 (LT).

                                                   

                                                  The problem does not occur for instance with Apple ProRes 4444, H.264, Animation, Apple Intermediate Codec.

                                                   

                                                  However, the problem gets even more strange: I took a detail image with Grab.app (screen grab), and noticed that when I view the Program Monitor image enlarged to 400%, the "pixels" in the image look very strange. These "2:1" pixels in the problematic preview file are divided into "vertical zones". But the pixels in non-preview-rendered image are normal square pixels. Please, find attached an enlarged example image.

                                                   

                                                  preview example 2.jpg

                                                  • 22. Re: Preview file rendering halfs the resolution
                                                    SimonHy Level 2

                                                    How is your Cinema Display connected?

                                                     

                                                    I'm guessing it's just a display issue.

                                                    • 23. Re: Preview file rendering halfs the resolution
                                                      Jim_Simon Level 8
                                                      The problem does not occur for instance with...

                                                       

                                                      Well, whatever the cause, it looks like you at least have a solution.

                                                      • 24. Re: Preview file rendering halfs the resolution
                                                        lastala Level 1

                                                        As stated before, the problem occurs both on the laptop screen and the external Cinema Display - and it happens also on the laptop screen even when the Cinema Display is not hooked on. So, it's hard to believe it is a display problem. I have hooked the Cinema Display via DVI, my laptop has DVI output.

                                                         

                                                        I do not think I have a solution! The reason is that I work with Apple ProRes 422 in general, I like that codec. Why should I be forced to use something else just because PP has a flaw. If the problem is in PP, it should be repaired. I'm also working between many applications, not only Premiere Pro. As stated before, the exported ProRes files also have the problem in PP, not only previews. Working in PP with exported files from PP is not possible if the application don't show them correctly.

                                                         

                                                        I mean, if you have a car that has malfunctioning gears - let's say you would need to change to reverse by opening the hood  - you wouldn't say there's a solution. I would expect the software to work properly with Apple ProRes, if there should have been that option in the very beginning.

                                                        • 25. Re: Preview file rendering halfs the resolution
                                                          Jim_Simon Level 8

                                                          Why should I be forced to use something else just because PP has a flaw.

                                                           

                                                          For the very simple reason that what you want to do isn't working.  So...you change to something that does work.

                                                           

                                                          I mean, if you're only vehicle requires you to go under the hood in order to make it work, then you'd better get your hands dirty or you ain't going anywhere.

                                                           

                                                          You're the first to come here with this problem.  For the majority, ProRes seems to be working just fine with CS6.  At this point, we still don't have a definitive reason why it isn't working for you.  Until we do, you have a way to get the job done, which ultimately is the goal here, right?

                                                          • 26. Re: Preview file rendering halfs the resolution
                                                            SimonHy Level 2

                                                            lastala wrote:

                                                             

                                                            Cinema Display via DVI, my laptop has DVI output.

                                                             

                                                             

                                                            What you have is an external monitor connected, not "external monitoring". It's a computer monitor, and will have the same issues with the way Premiere displays images as your laptop screen.

                                                             

                                                            If you really want to see what's going on with your footage, you should connect with something like this: http://www.blackmagic-design.com/products/ultrastudiosdi/

                                                             

                                                            Computer monitors aren't to be trusted. My colleague gets incredible amounts of tearing on footage when working from his laptop, but when output to a proper external monitor we can see the images are actually fine.

                                                            • 27. Re: Preview file rendering halfs the resolution
                                                              josephs51576386 Level 3

                                                              Agreed I learned a long time ago if it's being run from a computers GPU you can't trust it.

                                                              • 28. Re: Preview file rendering halfs the resolution
                                                                lastala Level 1

                                                                I have not claimed that I use external monitoring, I have said that I use an external monitor (Cinema Display). I have not claimed that Cinema Display would be the perfect reference monitor. However, I would expect that the software I have invested into, would draw all the pixels supposed to be in the preview or exported image - not just half of them. I would have the courage to claim that CinemaDisplay would play all the pixels in the preview or exported file, if the software was playing them correctly. As I have stated several times here, Premiere Pro and the CinemaDisplay plays the video files and all pixels when the file is not preview rendered or exported with ProRes422.

                                                                • 29. Re: Preview file rendering halfs the resolution
                                                                  Level 4

                                                                  It looks to me like an "aliasing" problem.  I am suggesting you search ( google, speak to other users using the same workflow you are, etc. ) about " aliasing " problems with your display of rendered pro res 422 files.  If you focus on 'aliasing' issue, instead of calling it half resolution and so on, it probably will address your problem faster because people with that problem will know what you mean.

                                                                   

                                                                  I posted this earlier and gives a hint what I am referring to.

                                                                  http://forums.creativecow.net/thread/2/1007725

                                                                   

                                                                  I am wondering if in the render of the source ( pro res 422 render ) you are losing that color information indicated by the " 2 ".  As you dont experience problem using animation and pro res 444, that is my guess.. that you are losing the color info...hence the problem of aliasing.

                                                                  What blows my mind though , is that you don't see the aliasing when you go to AE with the same rendered file.  That is just downright weird.

                                                                   

                                                                  I don't know if you want to actually solve the problem ( find out why this is happening really )... or if you are just fixated on blaming the software for something you want to work differently.  I think solving the problem may involve doing some more steps on your part.  For example, have you taken the rendered file ( or ftp to someone etc ) to another computer like yours... to see if they also see the same thing ?

                                                                  If they don't see the same thing, if it is OK on their computer, then maybe it's your graphic card or graphic card 'settings' causing the problem.

                                                                   

                                                                  Have you spoken to anyone at an apple store about this ? They may have heard of this problem from other users... and if you have a store nearby, you can take the rendered file there and see if it looks OK on their computer.

                                                                   

                                                                  I do wish you luck finding out whats going on, and am personally interested in what you find out ( which is why I keep looking at this thread ). I know lots of people who use pro res and also use it on motion picture 'sets' while shooting... at the DIT station or at video playback, to look at basic playbacks ( usually with some basic color correction etc , like rec709 or whatever )...So what you want to do is actually being done, but I just moved to MN from nyc and dont work in movie biz anymore and dont want to get involved with hooking you up via ftp to some local 600 people.

                                                                   

                                                                  First step I think is for you to keep an open mind and start dealing with the aliasing issue and try to see if others see the same thing on similar machine as yours.

                                                                   

                                                                  Or else think of some other way to solve the problem... cause nobody else I know has ever seen this or I would have heard of it I think.

                                                                  Also, this is a users forum, not adobe technical support... have you called them ?  So please be patient with users here trying to help you, as we are just people who try to help when we can and don't work for adobe.

                                                                   

                                                                  Thanks and good luck, and please let us know what you find out cause this problem is very weird.

                                                                   

                                                                   

                                                                  • 30. Re: Preview file rendering halfs the resolution
                                                                    Level 4

                                                                    caveat:

                                                                     

                                                                    I imagine you are rendering pro res 422 to see smoother effect or transitions, etc, as otherwise I dont know why you would even render something to itself ... but anyway, no sense yappin about doing things differently so you just get something to 'work' well... as you have the drive space problem for animation and 444 and so on...and who knows how that would export eventually for you.

                                                                     

                                                                    sure is a weird problem. If I think about it...say you take red raw and go to pro res and export... OK, so you lose some color info etc.. it looks flat and you fix it up etc... now you have the pro res...

                                                                    now you take THAT and render ( essentially taking something and doing it twice ) and lose MORE color info..which is sorta starting to get into a process I know nothing about...obviously... or I would have told you.

                                                                     

                                                                    sure is weird...

                                                                    • 31. Re: Preview file rendering halfs the resolution
                                                                      Level 4

                                                                      just googled some more...found this , and they are calling it 'pixelated edges'... which would be another word to use in google search for answers...

                                                                       

                                                                      http://blog.bertonevisuals.com/page/3

                                                                       

                                                                      excerpt:

                                                                       

                                                                      Some people are emailing me asking if it is really worthy to shoot with the Alexa and the Codex. My answer is: it depends! Some people might be happy to shoot Apple Pro Res in Rec 709 color space and just edit the clips right away in a non linear editing system. However, if somebody wants to do color correction and subsequent grading, the Arri Raw workflow is strongly recommended. Indeed, is not just a matter of the higher resolution 3K vs HD, but more importantly, it’s the ability to pull perfect keys during DI that otherwise (with the Pro Res) would have pixellated edges. The Arri Raw allows you to change the EI (exposure index) and the T stops that otherwise would give you much less latitude to play with, even if the footage was shot in Pro Res Log C.

                                                                       

                                                                      OK...off to food shop...good luck