10 Replies Latest reply on Mar 2, 2011 11:59 AM by Dave LaRonde

    Repairing or patching a quicktime

    ian.shook

      Hi guys. As most of you know, rendering a movie can take hours (or days). Lets say I export a Quicktime (H.264) and I notice a single frame that's incorrect. Is there any way to re-render the quicktime in only that one spot to 'repair' it? Instead of re-rendering the whole darn thing?

        • 1. Re: Repairing or patching a quicktime
          Mylenium Most Valuable Participant

          That's why people use image sequences and assemble/ convert them in a later step...

           

          Mylenium

          • 2. Re: Repairing or patching a quicktime
            ian.shook Level 1

            I have images that I used as a sequence. (about 4000 EXR files). I'm saying after I create a Quicktime animation in AE, is there a way to adjust something in AE and then re-render (from AE) just a part of the animation and patch my large Quicktime that is already exported.

            • 3. Re: Repairing or patching a quicktime
              Mylenium Most Valuable Participant

              No. It's simply illogical. Think about it: In order to process effects, AE must for all intents and purposes decode the original data, regardless of its compression. that being so, it loses all relation to the source file. Aside from that, even stream patching in MPEG files or using e.g. Quicktime Pro's ability to use copy&paste "editing" to merge streams is limited and will in most case entail re-rendering the file simply because the data structures changed. And you fundamentally misunderstood my comment about image sequences: Nothing stops you to render an image sequence from AE, re-import it, render it to a clip. If needed you then then only re-render segments and recompile a clip. nobody forces you to re-run all the effects processing based on your original EXR files and since you seem to only be outputting to H.264, there's nothing wrong to render 8bit TIFF sequences. Even my 4.5 year old machine at work can play them in realtime and render a clip from 4000 frames in under 10 minutes...

               

              Mylenium

              1 person found this helpful
              • 4. Re: Repairing or patching a quicktime
                Dave LaRonde Level 6

                Moreover, rendering H.264 in AE isn't good practice. 

                 

                H.264 gains image quality through multipass encoding, but AE can't do that; it renders one frame at a time.  It's better to render lossless out of AE, then use something else to encode to H.264.  Adobe Media Encoder comes to mind, so does Apple's Compressor and Sorenson Squeeze.

                • 5. Re: Repairing or patching a quicktime
                  ian.shook Level 1

                  If it took 10 minutes on my machine, I wouldn't be asking the question. It's pulling thousands of files from the network. A 4000 frame animation with basic color adjustments and motion graphics takes about 2.5 hours.

                   

                  If I understand what you're saying, you're suggesting to re-import the not-quite-perfect Quicktime file and use it as a track so I don't have to re-render the part of the quicktime that was correct.

                   

                  Is that right? Should I be worried about re-degrading the quality of the animation?

                   

                  Regarding 8bit TIFF sequences, that doesn't give me the control that an EXR files does. I don't understand why you're suggesting that.

                   

                  Thanks for the help,

                  Ian

                  • 6. Re: Repairing or patching a quicktime
                    ian.shook Level 1

                    I only recently was asked to render compressed quicktime out of AE. I generally go lossless like you said. I believe time was a factor in that decision to run with h.264 out of AE.

                    • 7. Re: Repairing or patching a quicktime
                      Mylenium Most Valuable Participant

                      Regarding 8bit TIFF sequences, that doesn't give me the control that an EXR files does. I don't understand why you're suggesting that.

                       

                      Umm, you said yourself that your final output format is H.264 which is an 8bit format with chroma undersampling?! Again, I think you are still completely misunderstanding what I said. If your initial pass is based on EXR files and you have done all your adjustments, the results of all your operations will be contained or "baked" in the output pixels. That being so, nothing stops you from rendering another set of TIFFs or whatever from the short segment that you fixed and merge it with the other already rendered TIFF sequence. Are you following me so far? I'm not suggesting to render 8bit TIFFs from your 3D app or whatever, just the pre-finals as the last step before actually converting them to a clip!!!!!!! Or in your own reply to Dave:

                       

                      If I understand what you're saying, you're suggesting to re-import the not-quite-perfect Quicktime file and use it as a track so I don't have to re-render the part of the quicktime that was correct.

                       

                      Yes, yes, yes! Exactly that, just with TIFFs.

                       

                      Should I be worried about re-degrading the quality of the animation?

                       

                      You should, if as you currently do, use H.264. To be blunt: it's not smart and the most atrocious thing you can do. Lossless image formats such as TIFF will not degrade nor will compressions like Quicktime animation or PNG.

                       

                      If it took 10 minutes on my machine, I wouldn't be asking the question. It's pulling thousands of files from the network. A 4000 frame animation with basic color adjustments and motion graphics takes about 2.5 hours.

                       

                      Well, if you always work based on teh original files and re-render everything.... But that is neither what Dave or I were suggesting. You really need to establish an intermediate workflow as described. Your current model is highly inefficient and you will never get anything done if you work liek this on every project.

                       

                      Mylenium

                      • 8. Re: Repairing or patching a quicktime
                        ian.shook Level 1

                        I agree on the workflow issue. I feel like I'm putting all my eggs in one basket when I cut my Quicktime out of AE. Maybe this is a dumb question, but what is the point of rendering out a sequence of 8bit TIFFs if I just have to re-render the TIFF sequence to get my final (uncompressed) Quicktime? Does having only a TIFF sequence make it really fast to create the quicktime compared to the EXRs + adjustment layers?

                         

                        I'm sorry if there's confusion between what is being said.

                        • 9. Re: Repairing or patching a quicktime
                          Mylenium Most Valuable Participant
                          Does having only a TIFF sequence make it really fast to create the quicktime compared to the EXRs + adjustment layers?

                           

                          Yes. Think about it:

                           

                          Read TIFF file --> Write frame to MOV

                           

                          is definitely shorter than

                           

                          Read EXR --> Apply effect A --> Apply effect B --> Move layer --> Write to MOV

                           

                          for example. So once you have your intermediates, you eliminate all the processing and do just the encoding/ compression and that can then be real, real fast. Which format you specifically use as the intermediate is your choice and sometimes it may even be necessary to render out EXRs or 32bit TIFFs, but even then you stil lsave processing time and because you only have to deal with one sequence as opposed to possibly multiple ones in teh original render you go easy on your I/O and network bandwidth... It's a win-win situation, you may just need to think about buying another harrdrive for storage...

                           

                          Mylenium

                          1 person found this helpful
                          • 10. Re: Repairing or patching a quicktime
                            Dave LaRonde Level 6

                            ian.shook wrote:

                             

                            what is the point of rendering out a sequence of 8bit TIFFs if I just have to re-render the TIFF sequence to get my final (uncompressed) Quicktime?

                             

                            Think of it as insurance: by rendering an image sequence, you only need re-render a limited number of frames if you make a mistake or the render goes bad for unknown reasons.  In your case, AE will already have done the heavy lifting with the exr's and motion graphics to create the 8-bit tiff sequence. 

                             

                            When reimported (from your own hard drive) and rerendered as a QT, the process will go as fast as a certain stinky, disgusting brown substance through a goose.