7 Replies Latest reply on Oct 21, 2010 1:08 PM by Mal_Reed

    H.264 for iPad, problems in CS5 - OK in CS3 (Mac)

    Mal_Reed Level 1

      Hi all,

       

      I have a CS3 project built on a PC, I've just brought into CS5 on a Mac. The encoding setup is for iPad, running full screen: H.264, 25fps, 1024x768, with a keyframe every 5 frames. I'm using the same setting as the CS3 project.

       

      All movies out of CS3 are reported by Quicktime to be 25fps. However movies out of CS5 are reported to be 25.33fps. In addition the results look blurry and generally poor compared to CS3 for the same file size. Anyone have any advice or experiencing similar issues?

       

      Mostly I need to ensure it comes out at 25fps as the engine/code base require 25fps with a key frame every 5 frames for movies to work correctly in App (as it has been doing with CS3 exports).

        • 1. Re: H.264 for iPad, problems in CS5 - OK in CS3 (Mac)
          Todd_Kopriva Level 8

          Have you installed the Premiere Pro CS5 (5.0.2) update? That update fixes a lot of problems.

           

          Can you confirm that the sequence settings in the CS5 project are the same as in the CS3 project? Basically, I'm trying to figure out if the problem is in the sequence (and therefore in the conversion phase from the CS3 project to the CS5 project) or in the encoding/exporting phase.

           

          Are you getting these same problems when you create a new project, or just when you convert this CS3 project?

          1 person found this helpful
          • 2. Re: H.264 for iPad, problems in CS5 - OK in CS3 (Mac)
            Mal_Reed Level 1

            Todd,

             

            Thanks for the feedback. I'm updating my CS5 suite now and will test the output again before supplying more info.

            • 3. Re: H.264 for iPad, problems in CS5 - OK in CS3 (Mac)
              Mal_Reed Level 1

              Had trouble updating Premiere initially, had to uninstall and do it all from scratch. I am now updated with 5.0.2

               

              I have rebuilt a couple of the sequences to see if I still get errors. From a newly created project in CS5, I am getting an odd frame rate reported from Quicktime from one of the two sequences I've rebuilt. All the video going into the Project is H.264, 25fps, 1024x768.

               

              In this test I have two sequences which share the same custom preset. Here are the sequence settings.sequence.png

               

              Here are the custom export settings I am using for both sequences.

              MediaEncoder.png

               

              Here are the two different frame rates I get as a result. The odd one being the first with a FPS: 25.35

              I've exported both sequences a few times, and the FPS is always the same for both sequences. It doesn't appear to be random.

              It's it may also be significant that in the movie with the incorrect FPS, the Data rate is also lower than the 'low' setting in the encoder settings.

              QuickTime_inspector.png

               

              As a separate issue...

              There are still errors with some sequences imported from CS3. The errors seem to be related to the fact that the sequence requires a crop to export.

              I'm not as concerned about these, as for my purposes, moving forward with new projects is more of a pressing issue. Although it may well be a genuine issue, so I'd be happy to look into this more.

              • 4. Re: H.264 for iPad, problems in CS5 - OK in CS3 (Mac)
                Colin Brougham Level 6

                What happens when you open the file in QuickTime Player 9, instead of QT X? I'm on a PC here, so I can't test that, but using your exact settings and playing the resulting file back in QT 9, I get a Movie FPS of 25 but a Playing FPS that fluctuates between about 12 and 27. It would appear that QT X doesn't differentiate between those two, so it's anyone's guess which value you're actually looking at. What happens if you change your bitrate encoding mode from VBR to CBR?

                 

                Could you upload a test encode somewhere that we could take a look at? That might reveal some clues.

                • 5. Re: H.264 for iPad, problems in CS5 - OK in CS3 (Mac)
                  Mal_Reed Level 1

                  Colin - I installed QT 7 on my Mac (seems that's the last version available) and I also tried adding the movie to Premiere to see what it report the FPS as. I get 3 different results, although I'm inclined to believe that it is playing at 25 FPS.

                   

                  (all the listings here are for the same movie)

                  • QT X reports - 25.35 FPS (playing FPS not listed)
                  • QT 7 reports - 25.07 FPS (playing FPS: 25)
                  • Premiere reports - 25 FPS

                   

                  Would you say this means I am actually getting 25fps? (I can't upload this movie as it's under NDA with the client)

                   

                  Assuming that is correct I am still wondering about the Data Rate, appearing (in QT) to be below the range listed in the Encoder settings.

                  Using variable between 4 - 8Mbps yet the output is reported as:

                  • QT 7 - 3837.74 kbits/s
                  • Premiere is says Average Data Rate: 463 KB / second

                   

                  Changing to CBR with 5 Mb/s

                  • QT 7 reports - 25.07 FPS (playing FPS: 25) - 4128.64 kbits/s
                  • Premiere reports - 25 FPD - Average Data Rate: 498 KB / second

                   

                   

                  Is Premiere the best place to check for data rates and FPS? Could do with one reliable source

                   

                  • 6. Re: H.264 for iPad, problems in CS5 - OK in CS3 (Mac)
                    Colin Brougham Level 6

                    Whoops--yes, QT 7 is what I meant but not what I said!

                     

                    (all the listings here are for the same movie)

                    • QT X reports - 25.35 FPS (playing FPS not listed)
                    • QT 7 reports - 25.07 FPS (playing FPS: 25)
                    • Premiere reports - 25 FPS

                     

                    Would you say this means I am actually getting 25fps?

                     

                    Without having much scientific evidence to go on, I would have to say "yes." Since software playback is not strictly timed the way, say, a professional video tape playback would be, there is bound to be some variability in how that file actually gets played back. It will vary based on the host computer, the file, and the player used. Ultimately, though, it's the way the file is encoded that matters, and I believe that the file actually is 25fps as you've specified.

                     

                    The most important question is: have you tried one of these CS5 exports in your destination application to see if everything works correctly? If they do, I don't think you have to worry about too much more; after all, based on your description, the most important factor is that you have keyframes encoded into the video stream for navigation/cueing. If this works, the playback framerate should be largely irrelevant, at least in how it is reported in a host of different playback applications.

                     

                    I am still wondering about the Data Rate, appearing (in QT) to be below the range listed in the Encoder settings.

                    Using variable between 4 - 8Mbps yet the output is reported as:

                    • QT 7 - 3837.74 kbits/s
                    • Premiere is says Average Data Rate: 463 KB / second

                     

                    Changing to CBR with 5 Mb/s

                     

                    • QT 7 reports - 25.07 FPS (playing FPS: 25) - 4128.64 kbits/s
                    • Premiere reports - 25 FPD - Average Data Rate: 498 KB / second

                     

                    There is bound to be some variation between the data rates of two files encoded even with the same encoding parameters, particularly when you're using VBR (variable bit rate) encoding. The amount of used bits will vary throughout the course of an encoded video stream, as some portions will require more bits to encode cleanly, while others can be compressed much more efficiently and therefore use fewer available bits. A busier video will require more of the available bits than one with less action. This would account for variations in data rate between two files using the same encoding settings.

                     

                    Now, if you are talking about the difference between what QT7 and Premiere report as far as data rate is concerned--that's simply a reporting issue. QT7 is using kbits/s, or "kilobits per second," whereas Premiere is being far less precise with kBps, or "kilobytes per second." One kilobyte per second (1 kBps) is roughly equal to eight kilobits per second (8 kbps), so if you multiply one the Premiere-reported data rates by 8, you get the QT7 rate.

                     

                    For example: 8 kilobits x 463 kBps = 3704 kbps; fairly similar to what QT7 reported.

                     

                    Why the difference? Well, one may be factoring in audio bitrate as well as video bitrate, or the Premiere reported data rate is less precise, or maybe just the fact that binary math is a little more involved than simple straightforward calculations In any event, they're both "right;" it just depends how accurate you need to be.

                     

                    Is Premiere the best place to check for data rates and FPS? Could do with one reliable source

                    My recommendation would be MediaInfo; it's available for many platforms, including Mac, and gives a great deal of information about any particular file.

                    • 7. Re: H.264 for iPad, problems in CS5 - OK in CS3 (Mac)
                      Mal_Reed Level 1

                      Thanks for the detailed feedback, I've not tried them in app as yet, but will do. Thanks for the application suggestion, I'll get it installed.