10 Replies Latest reply on Jan 15, 2009 9:48 AM by Jim_Simon

    Smart rendering HDV

    Tpfkas
      Hi guys,
      From what I undertsand is that CS4 re-renders every frame when you export HVD back to tape. Is that correct?
      Is there a noticeable quality loss when doing so?
      Is the Mainconcept HD plugin worthwile from this point of view?
        • 1. Re: Smart rendering HDV
          Tpfkas Level 1
          Bump: nobody???
          • 2. Re: Smart rendering HDV
            Curt Wrigley Level 4
            Under what scenario would you capture hdv, not edit and send back to tape?

            The problem with HDV is its long GOP temporal encoding. You need several frames in order to build one frame. So, even doing a simple cut may require that GOP to be re-rendered as you have cut a frame that affects other frames (needed for the temporal encoding).

            This is the challenge of editing native hdv. This is why other NLEs such as FCP convert HDV to another codec before editing.

            Most editors try to get the video out of hdv as soon as possible and not put it back to that format. There is quality loss of multiple generations of hdv encoding. More than you will see for DV AVI for example.

            Whats the solution? Sort of depends on what you are doing. Describe what you are trying to accomplish.

            Curt
            • 3. Re: Smart rendering HDV
              Tpfkas Level 1
              Hi Curt,

              You're the Curt form the site with these great tutorials? If so: I've been admiring your work over there for many years and learned some good stuff over there. Compliments.

              About the topic. I have been working with DV for many years. My workflow has been as follows: import DV-AVI, edit, export back to tape for high quality archiving purposes + encode to mpeg-2 for DVD-authoring. When export to tape I have always turned off the "recompress settings" in Premiere so that unaltered frames are original quality and not recompressed.

              I stepped up to HD recently after my old DV camcorder broke down. I choose for HDV i.s.o. AVCHD because I still think that tape is convenient for high quality storage and I can do the editing without investing in a complete new postproduction system and I could continue the workflow as I was used to. Now it turns out that when the edited movie is exporting back from the timeline to tape that every individual frame is being recompressed (at least, so it seems). I can understand that this is going on in the altered frames and the frames in the same or neigbouring GOP's.

              So therefore I took a look at the Mainconcept plugin which promises that it does smart rendering. Question is: is it worthwhile to use it for exporting back to tape or is the quality loss that I can expect from one recompression (from timeline to tape) to be marginal?
              Or would you recommend another workflow?

              Your feedback is appreciated.
              Ton

              (BTW: In the past I have looked at their plugin for mpeg editing in Premiere which I wanted to use for material that I only had on DVD, but I have to say that I never got it to work properly. I remember a very long thread on their forum with a lot of complaints about that plugin).
              • 4. Re: Smart rendering HDV
                Curt Wrigley Level 4
                Thanks for the kind words.

                I have not used the main concept plugin myself.

                I think there are two camps. One who keep everything native, and those who convert the hdv/mpg2 to something else to edit.

                Those in the 2nd camp in my unscientific survey choose cineform more often that not for that environment. The cineform codec is effecient, gets the video out of temporal compressions, allows you to use a slower machine, has "no visable" generation loss - At least much less than hdv. Once your footage is in cineform codec you can treat it much the same as you did DV, with the exception of export to tape. If you export to hdv, you re-introduce the temporal encoding. Many export whole projects to harddrive, or bluray disk.

                The first camp is a bit simpler as there are no plugins to update, but you need a beefier machine for the same performance. And you can still save the entire project to HD or Data Bluray for storage. You can export out to tape; but I wouldnt do more than one generation.

                Curt
                • 5. Re: Smart rendering HDV
                  Tpfkas Level 1
                  Hi Curt,
                  Thanks for the prompt reply.
                  I am aware of these two different options and I did have a look at the Cineform codec, but that is also a quite costly option.
                  Any idea how much quality I will loose recording back to tape?

                  Storing the whole project including the original files on BR is an option; I just wonder how reliable that is. I have had too many bad experiences with home burned DVD's...

                  Talking about BR: maybe I also think too old fashioned. Can it be that when I encode the final movie to High Quality Bluray and burn it to Bluray, will it match the quality and there is no need for a tape back-up anymore.
                  To put it in another way: is the quality ratio between BluRay and HDV much better than the quality ratio between DVD and SD DV? (and I mean for consumer level encoders).
                  • 6. Re: Smart rendering HDV
                    Curt Wrigley Level 4
                    I was a little fuzzy in my explanation. I meant export the Pr project to a data bluray disk or HD so the files would all be original quality. Export to Bluray for playback is gorgeous from my own experience. Most folks are used to looking at upscaled SD, or 720P from the cable company.

                    Curt
                    • 7. Re: Smart rendering HDV
                      Tpfkas Level 1
                      Your explanation to consider storing the original project on a data disk was perfectly understood :-).
                      I just now wondered if it is worthwhile doing at all to create such a back up. I certainly felt that way in DV, because the quality loss from DV to DVD is significant, even with the best available consumer encoders and highest quality settings. And I am certainly happy that I now have all my SD work back on tape: I can now create BR-discs from them which will be much better than the DVD's, even if the source material is SD.

                      But I still wonder if the quality loss going from HDV to BR disc (not as data but as movie) is so little that there is no need for original other archiving anymore. I did a quick test and found that the file size hardly decreases when encoding from HDV to H.263 Bluray with high quality settings, so a simple conclusion would be that there is not a while lot of quality loss. I can't realy judge yet, because I don't have a BR-burner and HDTV yet.
                      • 8. Re: Smart rendering HDV
                        joshtownsend Level 2
                        "quality loss from DV to DVD is significant"

                        Not if you save the .avi files on a data DVD. Don't convert your files to MPEG if your archiving.

                        Problem with burning as H263 is if you ever need to edit the footage again it's going to be ***** and you won't be able to use your project file.
                        • 9. Re: Smart rendering HDV
                          Tpfkas Level 1
                          Hi Josh,
                          Thanks for your input. Saving the DV-AVI files on a data DVD is not a very viable option because of it's size (around 13GB/hour).
                          That is why I have been playing them back on tape.
                          I don't realy need to edit the final result again, and I am therefor also not interested to save the project file itself. What I am looking for is saving the end result it in the best possible format as a master.
                          • 10. Re: Smart rendering HDV
                            Jim_Simon Level 8
                            >That is why I have been playing them back on tape.

                            Actually, you should save the original tapes for archive. If you ever need to rebuild/reedit the project, it's a simple matter of recapturing the original tapes. There's really no need for a tape master these days. A disk master and possibly a hard drive .iso as backup is all you really need for the finished product.