4 Replies Latest reply on Nov 28, 2012 1:44 AM by Clod82

    Keep original quality when exporting a sequence with AVCHD clips

    Clod82

      Hi all,

       

      As many of you, I create clips in AVCHD format, since this is the format used by most of new comomercial cameras.

      In particular, I use the action camera Contour GPS, with the setting 720p, 50 fps. According to the properties of the recorded clips, additional specifications are:

      • File extention: .mov
      • Codec: h.264,acc,text
      • Frequence: 13,178 bit
      • Pixel ratio: 1

       

      For sure Contour GPS does not record as a professional camera and the quality is not excellent in itself. In addition, consider that, going down fast with ski or bike, it is not easy for the camera to record all the details of the images.

      So, when editing, to me it is very important at least to keep the original quality of the clips…if I lose further quality, the outcome is unsatisfactory!

       

      There are two questions related to editing quality I am not able to answer:

      1. In order to avoid quality loss on the project, I create a sequence starting from the available preset AVCHD, 720p, 50 fps. Then, I put ACVHD clips in the timeline, without any correction or effect, just cutting and joining. Why the line of the timeline is yellow and not green? I would expect the render is not required! Maybe with this render I am loosing part of the quality…
      2. I tried to export the sequence as AVCHD, 720p, 50 fps, pixel ratio 1…I mean, the closest format as possible to the original clips….but I have a significant loss of quality!! Since the sequence is just the sum of clips (without correction or effects), is it possible to export it without transcoding? Or at least without loosing quality…

       

      I tried to find the answers in the forum and on other sites, but I was unsuccessful.

       

      Thank you very much for your support

      Ciao

      Claudio

        • 1. Re: Keep original quality when exporting a sequence with AVCHD clips
          Harm Millaard Level 7

          Cutting and joining requires a complete re-encoding of the long GOP format and thus quality loss. Nothing to do about that. The yellow bar means that your sequence settings and your source material do not match 100%. This may be caused by the .mov wrapper. You can try to create a new sequence from clip by right clicking on a clip in the project panel and see if that does not show the yellow bar. If it is still there, then is is the source material. The green bar only shows if you have force rendered the complete seuence.

          • 2. Re: Keep original quality when exporting a sequence with AVCHD clips
            Jim_Simon Level 8

            1. This has nothing to do with export quality, so it's safely ignored.

            2. You cannot export to any lossy format without losing quality.  To retain all the original quality, you'll need something lossless.  I recommend the UT codec in YUV420 mode.

             

            http://umezawa.dyndns.info/archive/utvideo/

             

            The only problem with this, however, is that it's not really much of a deliverable, meaning you can't put that on disk.  If you want a DVD or Blu-ray, you'll have ot go back to a lossy format.

            • 3. Re: Keep original quality when exporting a sequence with AVCHD clips
              joneisele Level 1

              Hi Claudio,

               

              I am new to PP CS6, a consumer, and recently edited my first movie from footage shot on a Contour+ video camera, similar to your unit.   Disclaimer here ...

               

              Are you sure your footage is 50fps?    My Contour+ shoots in "60p", which is technically 59.94 frames per second. 

               

              While what folks are saying here is true that any time you encode video using a lossy compression algorithm you will lose quality, I would not expect you to experience "significant" quality loss.   That was not my experience.   I am wondering if you have some settings off one way or the other.  I have noticed (as a consumer) you have to be meticulous about how you create sequences and in what form and especially how you export sequences.

               

              Perhaps go back as Harm suggested and create a new sequence based on the clip by dragging a clip onto the new item icon.  Drop in your footage.  Then try exporting with H.264 Blu-ray format, 720 59.94 preset, check maximum render quality, maybe VBR 2-pass and see what comes out.

              • 4. Re: Keep original quality when exporting a sequence with AVCHD clips
                Clod82 Level 1

                Hi Joneisele,

                 

                yes, I am sure the footage is 50p. When you set the camera with Storyteller, you can decide to use the PAL footage (25p/50p). Since I live in Italy, I prefer to use PAL settings as it is the European standard.

                 

                When I say "significant" loss of quality, I mean that if I export with a lossy format, I lose a lot of details of the original clips, although I export with the same format / quality as the original clips . For example (and I am thinking about cycling on a trail), in original clips I see all the single tufts of grass, while after exportig I see just a green layer with just some thfts. It is a pity!

                 

                Anyway, this weekend I will try to create a sequence from the clip and to export the sequence with a lossless format....and check the outcome. I think this solution will solve my quality issues.

                In addition, I will try different lossy formats to export a video to be uploaded on the web. Maybe, could be enough to use a preset setting like Vimeo HD to get a satisfactory outcome. I realized that Vimeo HD setting cut the footage to 25p, so I could try to increase the quality of export ...leveraging on the footage cutting to keep a small dimension for the file.

                Thanks