14 Replies Latest reply on May 6, 2011 10:01 AM by Jon-M-Spear

    Format advice appreciated

    Jon-M-Spear Level 4

      I natively edit in PAL 1080p 25.  I am producing a series of video compilations that are required as NTSC 1080 h.264 (They requested ProRes 422, but I am PC based!).  These will be played on large conference screens, so quality is paramount.  I'm unsure the play-in system will be.  (AJA Ki Pro is ProRes only)

       

      The compilation comprises material from many sources:  PAL XDCAM 1080p 25 footage; PAL 16:9 DV; NTSC edited material - some of which is 1080p, others have been ripped from DVDs and much is 720 x 480 16:9 DV.

       

      I will be keying the non-1080 material into a 1080 background, so I do not need to up-res it.

       

      So, most of the source material is NTSC, and it is required as NTSC h-264 1080p, so it makes sense to edit in NTSC.

       

      My question:  Can anyone please advise what codec/ editing mode they would recommend to produce the master compilation edit using PP5 (or PP5.5 trial), and what sort of bitrate/encoder setting should I be considering for the final outputs?

       

      Many thanks.

        • 1. Re: Format advice appreciated
          Jon-M-Spear Level 4

          Update:  Playback is through the Mac-based Playback Pro system.

          • 2. Re: Format advice appreciated
            Colin Brougham Level 6

            So, most of the source material is NTSC, and it is required as NTSC h-264 1080p, so it makes sense to edit in NTSC.

             

            Ignoring that HD is neither NTSC or PAL, I'd suggest using a 1080p/30p sequence. You've got a mishmash of all kinds of stuff, very little of it which has common characteristics, but I find that at least where frame rate is concerned, it's better to work at the highest-common denominator frame rate. If you've got more interlaced than progressive footage, perhaps 1080i/60i would be the better choice. Do you know whether you have to deliver an interlaced file or progressive file?

             

            ...and what sort of bitrate/encoder setting should I be considering for the final outputs?

             

            If you're for sure delivering an H.264 file, and they were originally requesting ProRes, they're expecting something fairly high bitrate. You can crank up H.264 and even set keyframes to 1, but that might make for a rather ungainly file. Do you have access to an FCP Mac? You could spit out an uncompressed file and convert to ProRes there. What about the Avid QuickTime Codecs? They're comparable to ProRes, and free for Mac and PC--and you can encode to it on a PC. They'd need the decoders installed on the Mac, though.

             

            A sticky wicket, indeed...

            1 person found this helpful
            • 3. Re: Format advice appreciated
              Jon-M-Spear Level 4

              Thanks for the reply.  Sorry about the PAL/NTSC thing.  Old habits die hard.

               

              So editing 1080p/30 it will be.  Without wishing to sound naive, which sequence preset would you use for 1920 x 1080 30p?  PP5 only seems to provide 1440 as an HDV preset.

               

              I've also learned that the h.264 must be in a .mov wrapper, rather than mp4.  I'm not that au fait with .mov encoding.  I've always tried to avoid it.  Do you have any advice on high quality encoding via AME5?

               

              Thanks once again.

              • 4. Re: Format advice appreciated
                Harm Millaard Level 7

                HDV is 1440 x 1080 by definition, AVCHD is usually 1920 x 1080 (square pixels). For export, assuming you are not on a MAC, you better refrain from QuiRcktime and .MOV formats. You are better off with plain H.264.

                1 person found this helpful
                • 5. Re: Format advice appreciated
                  Jon-M-Spear Level 4

                  Thanks for the clarification Harm.

                   

                  My sentiments exactly about h.264, but the American production company is playing the material into a conference live from a Mac using Playback Pro, and insist on the mov wrapper.  I can't seem to do anything to persuade them differently.

                  • 6. Re: Format advice appreciated
                    Colin Brougham Level 6

                    So editing 1080p/30 it will be.  Without wishing to sound naive, which sequence preset would you use for 1920 x 1080 30p?  PP5 only seems to provide 1440 as an HDV preset.

                     

                    Just roll your own preset. Use Desktop (or in CS5.5, now "Custom") editing mode, and set your parameters to match: 1920x1080, square pixels, no fields/progressive, timebase 29.97.

                     

                    I've also learned that the h.264 must be in a .mov wrapper, rather than mp4.  I'm not that au fait with .mov encoding.  I've always tried to avoid it.  Do you have any advice on high quality encoding via AME5?

                     

                    Yep, I have to use H.264 in MOV all the time--local FlipFactories don't eat Premiere's H.264 MP4s, sadly. Select QT as Format, H.264 as the Codec, and crank quality to 100. Set the rest of the parameters to match your source. The final IMPORTANT THING is to set your keyframe distance; for whatever reason, Premiere generates some awful output if you don't. I use a value that matches my frame rate; I'm usually doing 24p so I set it to 24, but in your case, set it to 30. Logic, for a high quality output, would suggest setting this to 1, but it inevitably looks like trash.

                     

                    Another option is to export an uncompressed AVI or MOV, and use MPEG Streamclip to do the same as above. It exposes a few more options that Premiere does not, and has traditionally given me really great output for H.264 MOVs.

                    • 7. Re: Format advice appreciated
                      Jon-M-Spear Level 4

                      Thanks Colin.  You've been extremely helpful indeed.

                      • 8. Re: Format advice appreciated
                        Colin Brougham Level 6

                        You're welcome. I would certainly recommend doing a quick test edit with a sequence set up this way; drop a few clips from each footage source into, and export out to a test MOV. Check it for any weirdness and other issues; you'll be better equipped to account for them now, instead of at crunch time

                        • 9. Re: Format advice appreciated
                          Jon-M-Spear Level 4

                          Good point.

                           

                          On the final issue of QT h.264, AME has an option to limit data rate.  It's default is 1,000kbps.

                           

                          Do you advise that I keep its default value?

                          • 10. Re: Format advice appreciated
                            Colin Brougham Level 6

                            No, be sure that is unchecked. That basically lets the encoder do what it has to do to maintain visual quality throughout an encode. You'd only use that if you were required to deliver a file of a specific maximum bitrate or file size; I assume neither is the case here. The Apple H.264 codec is, for all practical purposes, sort of hardwired--at least, the implementation in Premiere is hardwired. I just did a test export with this option off, limited to 50Mbps, and limited to 100Mbps--they were all within a few KB of each other. It's sort of a "hard limiter" instead of a target, like you would have if you used the Mainconcept H.264 encoder.

                             

                            I also need to amend my earlier statement regarding keyframes: technically, you can get a slightly better encode by setting keyframes to 1, but it's a pretty minor quality hike. The file I tested, first with keyframes set to 24 and then to 1, went from about 45MB to 78MB, and there is only a minor shift in quality--and that was looking at it at 400% magnification. So, do a few tests with these parameters to see what you like--but practically speaking, I think you could leave both keyframes and Limit Date Rate disabled.

                            • 11. Re: Format advice appreciated
                              Jon-M-Spear Level 4

                              Thanks.

                               

                              I have also done a test.  Unchecking the data rate doesn't default to 1,000kbps, as the dialogue box implied.  It's over 50 times that amount!

                               

                              Here are the properties from a mov h.264 set to 25 keyframes...

                              qt.JPG

                              • 12. Re: Format advice appreciated
                                Colin Brougham Level 6
                                Unchecking the data rate doesn't default to 1,000kbps, as the dialogue box implied.  It's over 50 times that amount!

                                 

                                Correct; that's what should be happening. If you check the box, you can constrain the bit rate (or data rate, as they call it); if you uncheck it, it's unconstrained up to a point. Actually, your test there confirms what I witnessed: the unconstrained export and the one limited to 100Mbps were exactly the same, whereas the one I exported at 50Mbps was just a teensy-tiny bit smaller. So, I think we can safely say that the functional bit rate of an unconstrained H.264 QuickTime export is around 50Mbps; you can't get any higher than that, at least with the way the encoder is implemented in Premiere.

                                • 13. Re: Format advice appreciated
                                  Colin Brougham Level 6

                                  I just did a quick comparison of two QuickTime H.264 exports:

                                   

                                  quicktime-h264.png

                                   

                                  You can see that the bitrates are clearly different, as are the GOP intervals. What's most interesting is that enabling keyframes forces an increase in encoding level!

                                   

                                  This indicates, though, that you can effectively create an I-frame only H.264 encode with the Apple H.264 encoder, if you disable keyframes. It requires a greater amount of drive space, but the file should be comprised of completely discrete frames.

                                  • 14. Re: Format advice appreciated
                                    Jon-M-Spear Level 4

                                    Hmmm.  Interesting.  Thanks.

                                     

                                    My tests continue late into the night..