18 Replies Latest reply on Aug 13, 2013 1:43 PM by Fuzzy Barsik

    Confused about previews vs renders vs final output workflow

    danzg Level 1

      I've read this article:

      http://blogs.adobe.com/premierepro/2011/02/red-yellow-and-green-render-bars.html

       

      ... but still confused.

       

      I'm used to FCP 7, where I set my sequence settings to the format of my final output.

      Then I render stuff as I work, and when I export, I use "current settings" - it's nearly instant, and it's the full quality I need.

       

      How do I replicate this in Premiere?

       

      That article says that if I use "Use Previews" when I export, then I'm NOT getting the full quality of the codec of my sequence. Is that correct?

       

      Are 'previews' rendered using the settings in the sequence setting?

        • 2. Re: Confused about previews vs renders vs final output workflow
          danzg Level 1

          joe bloe premiere wrote:

           

          What version of Premiere?

          Premiere Pro CC (v7.0.1)

          • 3. Re: Confused about previews vs renders vs final output workflow
            Sausagehead5

            So, all the documentation tells me never to use previews when exporting because it will degrade quality.

             

            My previews are always set either to Uncompressed 10 bit or ProRez HQ, so is Premiere somehow down-rezing my footage on export to lower than either of those codecs???

             

            Seems strange to me to claim "never use previews when exporting" when it all depends on how you have your preview settings set.

            • 4. Re: Confused about previews vs renders vs final output workflow
              danzg Level 1

              I just had a long chat with "Sandeep" from Adobe.

               

              He claimed that whatever codec I set my Video Previews to (under Sequence Settings), that is what will be used to render previews and will then be exported with "Use Previews" selected.

               

              Which is what I would expect, except for that article making things confusing.

               

              Now if there were only a way to render in the background ...

              • 5. Re: Confused about previews vs renders vs final output workflow
                Jill Woodward Level 1

                So if Sandeep is correct, would it be right to surmise that doing a preview render in high quality would save a little time on export? Or at least be closer to the FCP workflow described above by the OP? I'm confused by the documentation too, and the general concept of preview renders. I'm still new to PP altogether, and still getting my head around certain things.

                • 6. Re: Confused about previews vs renders vs final output workflow
                  jamesp2 Level 1

                  Impossible to know for sure, but it could be the advice not to use previews is based on the assumption that users won't select the final export format for their rendering codec, or that the system default rendering codec won't match the quality of the export codec.

                   

                  It's also possible that previews are subject to additional recompression, even when the preview and export codec are the same.

                   

                  Clarification would be grand.  Adobe?

                  • 7. Re: Confused about previews vs renders vs final output workflow
                    Fuzzy Barsik Level 4

                    If you choose a production codec for your previews and then export to the same codec, render time for final output is slight and the quality of the final render is identical to generated preview. You can test it on your own. I use the following technique for monitoring quality:

                    - in After Effects set my project in 32-bit and linearise working space for higher precision on blending;

                    - drop a pair of comparing footages into the same composition and set blending mode of an upper layer to Difference;

                    - the closer the result to pure black solid, the lesser the mathematical difference in pixels values.

                     

                    In the above case I get pure black solid.

                     

                    However, the question is whether you really want to set your previews, which are MPEG2 by default, to a production codec? In most cases an editor renders previews more often (if ever), than a final output, whereas rendering to a production codec takes longer, than to default MPEG2.

                    • 8. Re: Confused about previews vs renders vs final output workflow
                      Kevin-Monahan Adobe Employee

                      Jill Woodward wrote:

                       

                      So if Sandeep is correct, would it be right to surmise that doing a preview render in high quality would save a little time on export? Or at least be closer to the FCP workflow described above by the OP? I'm confused by the documentation too, and the general concept of preview renders. I'm still new to PP altogether, and still getting my head around certain things.

                       

                      Hi Jill,

                      In many cases, yes, it will save time on export. However, you have to use a codec that is capable of "smart rendering." In Premiere Pro CC, on Mac, ProRes can be used for smart rendering. So that is good news for those people coming from a FCP style workflow.

                       

                      Thanks,

                      Kevin

                      • 9. Re: Confused about previews vs renders vs final output workflow
                        danzg Level 1

                        From my experience of a few weeks, it seems that YES, setting your sequence settings to your final output format and then using "Use Previews" does reduce the time to export.

                         

                        But I'm confused why you would say that "rendering to a production codec takes longer." I would think that rendering to a long GOP format like MPEG2 takes longer, since there is far more computation required to do the compression AFTER the actual rendering. Are you speaking from experience? Have you compared rendering times between MPEG2 and, say, ProRes 422? I can see that using a different RESOLUTION or BIT DEPTH would make renders longer, but codec should be the opposite -- the less compressed, the faster ... no?

                        • 10. Re: Confused about previews vs renders vs final output workflow
                          Kevin-Monahan Adobe Employee

                          jamesp2 wrote:

                           

                          Impossible to know for sure, but it could be the advice not to use previews is based on the assumption that users won't select the final export format for their rendering codec, or that the system default rendering codec won't match the quality of the export codec.

                           

                          It's also possible that previews are subject to additional recompression, even when the preview and export codec are the same.

                           

                          Clarification would be grand.  Adobe?

                           

                          Hi jamesp2,

                          Yes, the advice given was for workflows prior to Premiere Pro CS6 (6.0.1) and CC. In Premiere Pro CC, many popular production codecs are now available for smart rendering. Check out this video tutorial from retooled.net for an explanation.

                           

                          I don't believe previews are subject to recompression, the data is merely passed through.

                           

                          Thanks,
                          Kevin

                           

                          • 11. Re: Confused about previews vs renders vs final output workflow
                            danzg Level 1

                            "Smart rendering" ?? What the heck is that?

                             

                            Are you saying an "ideal" workflow for us Mac-based, coming-from-FCP types is to set Sequence Settings > Video Previews to ProRes 422? What about "max bit depth"? I didn't think that Prores 422 had a "bit depth" option. And what about "Max Render Quality"? What does that do?

                             

                            And what if our final output is MPEG2? How do we streamline the render/export process? Use "I-frame only MPEG"?

                            • 12. Re: Confused about previews vs renders vs final output workflow
                              Fuzzy Barsik Level 4
                              Are you speaking from experience?

                              Does my comment look like I am not?

                              Default PrPro MPEG2 previews are encoded with the following setings: ~25.5 Mbps, GOP: M=1, N=3.

                              Run your own tests and compare render time.

                               

                              By the way, I'm on CS5.5. Hence, no smart rendering is involved when I set my previews and final output to e.g. UT Video.

                              What about "max bit depth"?

                              See this The Video Road blogpost - at the end of the article Steve Hoeg provides detailed explanation on how 'Maximum Bit Depth' works.

                              And what about "Max Render Quality"? What does that do?

                              See e.g. this discussion on 'Maximum Render Quality'.

                              • 13. Re: Confused about previews vs renders vs final output workflow
                                danzg Level 1

                                Fuzzy Barsik wrote:

                                 

                                Are you speaking from experience?

                                Does my comment look like I am not?

                                 

                                I was not questioning your "Experience," I was merely asking if, regarding this particular issue, you have done actual testing comparing render times. Sorry for the confusion.

                                 

                                And my other questions were directed to Kevin; should've quoted, sorry.

                                • 14. Re: Confused about previews vs renders vs final output workflow
                                  Fuzzy Barsik Level 4

                                  I merely tried to draw your attention to what had been said in my comment. Would it be possible to argue about identical quality without testing? Moreover, while providing testing technique description?

                                   

                                  And I can also see that you addressed your next comment to Kevin. How does it change the fact that my answer can contain some valuable info related to your question? I'm confused if I should provide some help in your other thread about Dynamic Link?

                                  • 15. Re: Confused about previews vs renders vs final output workflow
                                    danzg Level 1

                                    Fuzzy Barsik wrote:

                                     

                                    I merely tried to draw your attention to what had been said in my comment. Would it be possible to argue about identical quality without testing? Moreover, while providing testing technique description?

                                     

                                    And I can also see that you addressed your next comment to Kevin. How does it change the fact that my answer can contain some valuable info related to your question? I'm confused if I should provide some help in your other thread about Dynamic Link?

                                    On the contrary, your info was helpful. I was trying to clear up what I thought was some misunderstanding. I guess I misunderstood the misunderstanding.

                                     

                                    I saw what you said about quality, but it goes against my experience when you suggest that MPEG2 takes less time to render than ProRes (unless of course one has slow hard drives!)

                                     

                                    Regarding the "bit depth" and "max render q", I spaced out and thought that those were referring to the codec used for rendering; now I realize that it applies to the actual render process, it makes sense.

                                     

                                    Please do provide any insight you have about the Ae dynamic link worflow!

                                     

                                    thanks

                                    • 16. Re: Confused about previews vs renders vs final output workflow
                                      Fuzzy Barsik Level 4

                                      With that bitrate and GOP=3 it is fast. Otherwise it would be unwise (semi-pun intended) to exploit it as preview.

                                      • 17. Re: Confused about previews vs renders vs final output workflow
                                        danzg Level 1

                                        Fuzzy Barsik wrote:

                                         

                                        With that bitrate and GOP=3 it is fast. Otherwise it would be unwise (semi-pun intended) to exploit it as preview.

                                        Are you referring specifically to the "I-Frame Only MPEG" setting in Video Previews? Is that the "default" preview codec?