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Any real loss in transcoding to 720p?

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    Any real loss in transcoding to 720p?

    Hello, all!

    I was reading the Cineform tech blog, and their recommendations are to transcode 1080p footage from the HVX200/HPX170 to 1280x720p upon ingestion. Their reasoning is that the camera in 1080p can't really resolve greater than 1280x720p. I don't doubt it at all.

    What about the AF100? I have seen test results that indicate that the camera can resolve 800 lines, but others claim 700. I know even less about the effective horizontal resolution. Is the AF100 packing the gear to warrant a true 1080p post-production workflow? I am about to start a project involving several different cameras, and I'd be interested in any advice on the matter.

    Thanks!
    Chris

    #2
    I wouldn't do that.

    The question is what are the formats of the other cameras? What format do you need to deliver in?
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      #3
      Thanks for the response, Erik.

      The format will be Blu-Ray--I'm shooting another micro-budget feature. I haven't received enough rejections lately, so I figured I ought to get back to work.

      I will be using the AF100 primarily, but will be using the HPX170 for shots that need to be jello-proof. I might have a second unit working with a Samurai and a Z10000/GH2.

      I am fully prepared to go with the full 1080p workflow--that's what my instincts are telling me. I just ran across that blog entry and it piqued my curiosity. The AF100 sounds like it's closer to 720p than 1080p in terms of real resolution. Then again, if it really does resolve 800 lines, then that would be throwing away 9 or 10 percent of vertical resolution.
      Last edited by Christopher S. Thompson; 01-29-2013, 01:50 PM.

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        #4
        One thing to keep in mind, DVCProHD isn't 1920x1080, but 1280x1080. I'm guessing that that's part of Cineform's logic for recommending to just downrez to 1280x720. For the bandwidth, you're not really getting anything by converting it to 1920x1080. AVCHD is full 1920x1080 in resolution, so you would lose resolution downrezing to 720p.

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          #5
          You are correct about Cineform's logic. The disconnect for me is in the difference between the codec resolution (1920x1080) and the resolution decoded from the sensor, which is ????x800 or so? Or so I'm told?

          I guess the safest thing to do is to stick with 1080p, especially since I have no idea what the horizontal resolution is. Thanks for the advice!

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            #6
            I have an HMC150 (same sensor), so I should know that off the top of my head =/

            You might want to ask in the HPX170 forum, someone there should know for sure.

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              #7
              Have you thought of transcoding/downscaling everything to a DVCProHD mezzanine codec?

              It sounds like that's your lowest common denominator. It's a robust format and, if you're cutting on a Mac, it's an excellent native format - so you'll have a native workflow right through, with no compression/decompression (codec) loss.

              With my film editor's hat on, that would be my suggestion.

              But ultimately, you can't beat testing it for yourself. Go to any major studio and you'll always see armies of 2nd and 3rd ADs testing stuff in situ before the main unti moves in.

              Ben.
              Ben Giles BFE BAFTA

              www.matobo.co.uk

              @MatoboLtd

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                #8
                With tests I did some time ago with the HVX200, I found that it has slightly better detail when recording in 1080 rather than 720. I doubt that it would hold that difference if the 1080 were down-converted to 720.

                If it were me, I'd shoot in 1080.

                You certainly should run some workflow tests prior to starting the production.

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                  #9
                  If your editing with Premiere Pro CS6 you wont have to transcode anything.
                  YOUTUBE: https://www.youtube.com/user/ErikNaso
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                    #10
                    Originally posted by bengiles View Post
                    But ultimately, you can't beat testing it for yourself. Go to any major studio and you'll always see armies of 2nd and 3rd ADs testing stuff in situ before the main unti moves in.
                    That is what it will ultimately come down to. I was just wondering if any pixel-peepers had already figured it out.

                    I think I am going to stick with 1080p. I appreciate the insight you all have provided.

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