11 Replies Latest reply on Jul 4, 2009 10:40 AM by Jim_Simon

    Panasonic 24p footage - workflow in CS4

    Toffyka

      Hi there,

       

      Although it’s my first post on this forum I’ve been reading and browsing for answers to my questions before – it’s not the case for me to give advises, not yet at least!!!

      But this thread just confuses me a lot and I don’t think I fully understood the previous related discussions I’ve read. So here is my question:

       

       

      What’s the workflow in Premiere CS4 with DVX100 footage, 24pA (although I also have some 24p Standard – meaning 2:3:2:3 pulldown cadence) to obtain a 24p video with Nooooo interlaced artifacts?

      1. For      the 24pA, from what I reasoned myself and read on this forum, I chose      the 24p Standard present under DV-24p. Captured the footage      and applied the Interpret footage -> Remove 24p DV pulldown.  Set the in and out points; dragged      it on the timeline of a sequence (24p preset). None of the Source or the      Monitor windows show any interlaced artifacts and the timeline shows NO red line above. So it should be a 23.97fps footage, right?

      BUT, as soon as exported (in the Microsoft AVI format with, for e.g.,  the NTSC DV 24p preset) I DO see the video as interlaced in BSplayer, while with Windows Media Player it shows no interlaced artifacts. I thought that my BSplayer is configurated wrong, but, any further compression I apply to this like exported video (a DivX codec, for e.g.), gives me a new video file with interlaced look in BOTH players. I’m loosing my mind – where do I do wrong? Project settings? Export settings?

      (the footage was shot on tripod, but with a lot of motion in it - sport! And is designed to be exported for DVD and to be viewed on computer.)

       

       

      2.      How could I mix 24pA footage with 24p Standard footage of the same DVX100? As, for mistake, the 1st day I shot 24p Standard instead of 24pA?

      From what I  understood the 24p Standard need a 29,97 fps sequence – is it right?

       

       

      Thank you,

      Karmen

        • 1. Re: Panasonic 24p footage - workflow in CS4
          Colin Brougham Level 6
          1. The reason you see interlacing when you export an NTSC DV file is because NTSC DV is always 29.97 and is always interlaced, period. Even when you're recording "24p" using a DVX100 or similar camera, you're actually recording 29.97i--that's all that NTSC DV can ever be. The way that frames captured by the camera's imaging block are recorded to fields on a DV tape is what gives the look of 24p, and it's up to the software you use to edit to interpret the fixed 29.97i stream as 24p. It does this by simply discarding or ignoring the non-24p frames on playback, but they are always in the recorded or captured video stream. That's why when you export back to a DV AVI that you see the interlaced frames: they are reintroduced on export to create a DV-legal 29.97i stream. The only way you can avoid this, if you want a 24p AVI file as an output, is to use a different codec that can actually have a 24fps (read: 23.976fps) timebase and can be written as a progressive file. DV does not qualify for this purpose, for the reasons above. You could use a codec like Lagarith or no codec and export to an uncompressed AVI, or you could export to a high-bitrate I-frame-only MPEG-2 file, which is a common intermediate file around these parts.
          2. Both 24pA and 24p footage can be edited in a 24p sequence or a 29.97i sequence (again, see above for rationale). It's a common misconception that if you record 24p (not 24pA), that you have to edit on a 29.97i sequence--this is not the case. Footage that was recorded using the 24p cadence can be edited in a 24p sequence, almost as easily as 24pA can. It just means that the software needs to decompress, disassemble, reassemble and recompress the original 24p-recorded frames a little differently than with 24pA-recorded footage, which results in a very negligible quality hit to those frames that are decompressed/recompressed. In practice, it's virtually indistinguishable from 24pA footage, in my experience. Premiere should automatically remove the pulldown from 24p-recorded footage on capture, but if it doesn't, you simply need to select the clips and use the Interpret Footage function and select the Remove 24p Pulldown. You'll be able to edit both types of footage on the same timeline, without incident.
          • 2. Re: Panasonic 24p footage - workflow in CS4
            Jim_Simon Level 8
            Footage that was recorded using the 24p cadence can be edited in a 24p sequence

               

              You know, I've heard that.  But I don't see how it can be.  The whole point of developing 24pA was that normal 24p can't properly reconstruct the original frames for 24p playback.  At least one frame of the group is 'distributed' in the pulldown in such a way that it simply can't be later pulled out and rebuilt into the original whole frame.  That's why the cadence of 24pA was altered, to allow a correct rebuild of all the original frames.

              • 3. Re: Panasonic 24p footage - workflow in CS4
                Colin Brougham Level 6

                It works--I've done it dozens of times with hours of 24p (not 24pA) footage. The 24pA cadence wasn't necessarily designed to make 24p editing possible; it was designed to make 24p editing less taxing for a computer and somewhat higher quality, because a whole "frame" (and I say "frame" in quotes because there are no such things as "frames" in interlaced video) could simply be discarded.

                 

                I understand the logic of your thinking, but again, keep in mind that are no such things as frames in interlaced video. Each field is written independently, but we like to think of a video frame as being comprised of a top and bottom (or upper and lower, or odd and even) field because it's easier to comprehend that way. For the most part, this thinking works; that's the whole source of the "is it 30i or 60i?" nomenclature question.

                 

                Now, while I'm not too sure about the science or math of it--I try to stay out of the part--I believe the way that DV compression works is to package those two fields together as a "frame", simply for compression purposes. The fields are still independent, and can be recovered as independent entities, but it involves decompression to reverse the DV compression. Once you do that, you have two separate fields, and in the case of 24p, those independent fields can now be reassembled in the proper order to recreate 24 independent progressive frames. It is the 2:3 pulldown cadence that tells the software which fields it needs to use to recreate the independent frames. Of course, it's still DV, so in order for it to be played back properly, there must be a recompression step.

                 

                And this is why 24pA was invented. It's still recorded with fields, because it's interlaced DV at its heart, but the 2:3:3:2 cadence allows for the third "frame" of five to simply be ignored: everything the editing software needs to create a 24p stream is already encoded in the DV stream, without any decompression or reassembly needed. Recording using 24pA maintains a somewhat higher quality on those frames that would otherwise have to be reconstructed if the video was recorded with 24p, and there is theoretically less of an impact on computer performance because the decompression/recompression cycle is being avoid (though I doubt that has much bearing on any computer manufactured within the last few years).

                 

                I know it seems like voodoo, but that's really how it works (distilled a bit, I suppose!). Check out this article at Adam Wilt's website for more information, as well as some graphics that illustrate what's going on in 24p and 24pA recording.

                • 4. Re: Panasonic 24p footage - workflow in CS4
                  Jim_Simon Level 8

                  That page is the one I was thinking of.  To quote regarding the use of 24p: "The A, B, and D frames can be recovered by using two fields from the same 60i frame. The C frame cannot be..."

                   

                  But reading a little further, I see this.  "...recovering the C frame requires decompressing the green and magenta frames and recompressing them into a new, 24p DV frame. That puts the C frame a generation down compared to A, B, and D"

                   

                  I guess I just didn't recall that part.

                  • 5. Re: Panasonic 24p footage - workflow in CS4
                    Toffyka Level 1

                    Thank you Colin and Jim,

                     

                     

                    I knew about Adam Wilt’s material and that was exactly the reason I changed form 24p Standard to 24pA.

                    Thanks Colin for the explanation of the DV AVI functioning. Now, you gave me two alternatives for exporting .AVI using a codec that supports 24p timebase:

                    -         I don’t have the Lagartith codec;

                    -         And I have problems encoding in MPEG2 I-frame. I assumed that I have to set the M and N intervals to 1 and I found the confirmation in another thread (settings for MPEG-2 I-frames only). BUT, my Media Player won’t read the .AVI file exported with the following settings: 23.98 fps, profile: 4:2:2, level: high, bitrate 100 CBR, M frames and N frames = 1. The BS player reads it normal, but the Media Player reads only a black screen.

                    Also, I use the MPEG format for Audio, since the PCM gives me an error in Encoder that won’t allow me to precede any further. Why do I have two files after export?

                     

                     

                    An additional question: is the MPEG-2 I-frame file a good intermediate file intended for further editing?

                    What other alternatives do I have for a 24p timebase?

                     

                    Thank you again,

                    Carmen

                    • 6. Re: Panasonic 24p footage - workflow in CS4
                      Jim_Simon Level 8

                      Couple of things.

                       

                      First, you say it's sports material.  Shooting that in 24p (of any flavor) was probably a mistake.  It just won't come out as nice as good old 30i.

                       

                      Next, Premiere cannot write a proper 24p DV file, it always adds the required pulldown.  So a DV export from a 24p sequence will not look as good as it should.  To complicate matters further, Encore will always retranscode anything that is actually 24p (such as a Lagarith file) adding the required pulldown immediately upon import.  This negates the very purpose of having true 24p media.  The only exception to this seems to be with 24p DVD compliant MPEG, which has the pulldown flags inserted, rather than actual frames.

                       

                      So, for making a quality DVD from 24p source, you need to export out using the MPEG2-DVD preset, and make sure settings match your footage.

                       

                      For making a computer playback file, you could do the same, but turn on multiplexing.

                      • 7. Re: Panasonic 24p footage - workflow in CS4
                        Colin Brougham Level 6

                        Carmen,

                         

                        1. Lagarith is a free codec; you can get it right here. In fact, a new version was released just today.
                        2. WMP probably won't play back the MPEG2 I-frame file unless you have an MPEG2 decoder installed that WMP can utilize. Out of the box, it doesn't come with one.
                        3. Don't use MPEG audio. If PCM audio won't export along with the MPEG2 video file, just uncheck "Encode Audio" and export only the video. Then, duplicate your encode queue item and change the format to Windows Waveform (assuming you're on Windows).
                        4. You end up with two files because multiplexing doesn't seem to work with I-frame files generated by AME. Not a big deal, as you can stitch these together with most encoding programs.
                        5. MPEG2 I-frame could be used for further editing, I guess, but it's not optimal. What do you mean by "further editing"? Why not just keep the original project and media and archive it?

                         

                        OK, that all said, I guess I missed the part about you wanting to create a 24p DVD. You can do this with AME, and get a pretty decent result. Send your project to AME, select MPEG2-DVD as your format, and select 23.976 as your frame rate. Set M frames to 2 and N frames to 12. Set up the rest of the settings as necessary for your project (PAR, bitrate, audio, and so on). This will create a true 24p MPEG2 file and will insert the proper pulldown flags for playback on an interlaced television. What's cool about creating 24p DVDs is that you get 20% more bandwidth to play with because you're only encoding 24 frames per second versus 30 frames per second. As such, you can keep the bitrate the same as you would for a 30i DVD, and end up with a somewhat better image, or you can knock the bitrate down by 20% and have the same level of quality as the 30i DVD, and be able to fit a 20% longer program on the same capacity disc.

                         

                        Or, are you using some external encoder that you need a 24p AVI file for? What's your workflow with this project?

                        • 8. Re: Panasonic 24p footage - workflow in CS4
                          Toffyka Level 1

                          OK, maybe it would have had a sharper motion in the picture with 30p, but I preferred the filmic look of the 24p as the sport footage will be included in a short-documentary video intended for emergent filmmakers festivals.

                           

                          Thank you Jim for the MPEG2-DVD suggestion – I’ve made an export test and I am pleased with the quality of the video.

                           

                          Carmen

                          • 9. Re: Panasonic 24p footage - workflow in CS4
                            Toffyka Level 1

                            Thanks Colin,

                             

                            1. I will      download it and try it on.

                            .

                            5.  I need to prepare some footage for one “sport-guy” so he can further use it in his showreels and presentations. I could just capture his “part” and make an uncompressed .AVI , BUT – a) I don’t have one tape anymore + b) the uncompressed .AVI file is just toooo big to be able to send him a DVD  (3 min almost 3Gb!!!). So, will it suit the purpose to use a lossy compression of the uncompressed AVI with an external encoder?

                             

                            6.  24p DVD should be the final output of the project + a 24p file for playback on the computer (which Jim has already pointed out!). Moreover I will prepare a version for the web which I usually prepare with an external encoder. Should you suggest me a preset for this, from within Encoder, that’s more than useful.

                             

                            I hope I won’t have to do any editing myself in the future!!! Just tooooo many codecs and presets.

                             

                            Thanks again,

                            Carmen

                            • 10. Re: Panasonic 24p footage - workflow in CS4
                              Colin Brougham Level 6

                              Carmen,

                               

                              For sending the footage to someone else, Lagarith is certainly an option, especially since the codec is freely downloadable. Lagarith isn't the best editing codec in the world--it's better suited as an intermediate that you'd use to send a finished project to an external encoder or for archiving--but I've used it successfully within Premiere. I can't speak to its usability within other editing applications, though.

                               

                              Here are a couple of other thoughts/options for sending the footage to the "sports guy":

                               

                              1. Export a 24p DV AVI, either from your original sequence, or just copy the clips he needs to a new 24p sequence and export that. Use Microsoft AVI as the format, and either select one of the 24p presets (to match your PAR) or select "DV (24p Advanced)" from the codec dropdown. Premiere will use advanced pulldown to create a 2:3:3:2 file, and the pulldown can be removed on import to Premiere (and I'm assuming most other editors) to recreate a 24p video stream.
                              2. Export your 24p sequence to miniDV tape. Once again, Premiere will use advanced pulldown (2:3:3:2) on export to tape, which you could give to the sports guy and he can either capture as 24p or 29.97, depending on the editing software he's using.
                              3. Use Project Manager to give him just the clips he needs. Create a new sequence and copy and paste into it the clips that you're going to give him. Go to Project > Project Manager, select thenew sequence you just created, select the "Create New Trimmed Project" option , and then include handles (30 frames or whatever is convenient). Set your destination, and hit OK. Premiere will create a new project and will trim and copy the clips that you want to send him. Now, unless he's using CS4, the trimmed project file itself won't be of any use, but you could send him all the trimmed media on a DVD or hard drive (depends how much there is). The clips will be 24p clips, and can have the pulldown removed on import (or manually, if necessary).

                               

                              For local playback, you could use H.264 or WMV, both of which can be good quality at manageable file sizes, and additionally, can have native 24p frame rates. These are web options as well, as would be Flash. It's hard to suggest a specific format or encoding settings without knowing how and where you plan to distribute the file. If you're using an external encoder, I'd suggest Lagarith as your intermediate file; most encoders will be able to read the file.

                              • 11. Re: Panasonic 24p footage - workflow in CS4
                                Jim_Simon Level 8

                                Thank you Jim for the MPEG2-DVD suggestion

                                 

                                No problem.  I've done a LOT of testing on this front.