5 Replies Latest reply on Oct 25, 2010 10:17 AM by Kevin-Monahan

    How to compress videos with camera motion for the web?

    Andy Bay Level 1



      I'm constantly hitting the same wall in my post production, so I finally decided to ask for opinions.


      I usually keep the camera moving slowly in all my videos, to give sort of a dynamic feel to the them.


      While editing and post processing my videos, in either Premiere or AE, everything looks very nice and smooth. The problem is when I need to compress the file for the web: what used to be a smooth camera move now looks jittery and jumpy.


      I understand this has to do with the compression. But how do I solve this problem? I'm usually compressing the videos using h264 with a variable bitrate of around 6. The container can be f4v or mp4. THe videos look very nice besides the jumpy camera movement.


      Please guys, do you have any tips on how to better compress videos with a lot of slow camera motion? Does the keyframe distance matter? Should I go even higher with the bitrate? Would CBR be better? Is H264 the weapon of choice or is there something better for my needs that sites like Youtube still support? What bitrate do you usually usem when the video is going to be uploaded to Youtube (or Vimeo)?


      Any help will be greatly appreciated!

        • 1. Re: How to compress videos with camera motion for the web?
          Mylenium Most Valuable Participant

          Actually the issue may be in the camera motion itself. The critical factor for MPEG compression  is the contrast differences from GOP to GOP or I-Frame to I-Frame. If the motion is too slow, there is no difference and the compression will re-use the same blocks forever. If there is too much motion with fine details, then there are almost inevitably blocks simply because a fine details such as a motionblur streak may be below the smallest block size or the overall amount of fine detail exhaust the data rate. Some of these things can be influenced by the choice of encoder and quality settings, of course, but not always. Contrary to what you think, decreasing keyframe intervals may only make things worse, as it will create more base keyframes which are always recalculated fresh without reusing previous motion analysis data. It is usually best to leave these things at automatic/ the default settings. Same would apply to trying to enforce CBR... however, from your description it sounds like you are doing the encoding directly from AE, and thus even the VBR does not produce such great results. Maybe you could try this in AME? That should make things better. As for otehr tricks - the usual "add some noise" would of course also work by visually breaking up reagions and continually randomizing block allocation, but it will also increase file sizes and data rates. If you downsize larger output, you may also consider adding a slight blur before resizing. This will distribute luminance more evenly across the image and also helps to get better compression. You can also directly  just blur the luminance using a channel blur effect...



          1 person found this helpful
          • 2. Re: How to compress videos with camera motion for the web?
            Kevin-Monahan Adobe Employee

            As Mylenium suggests, try compressing in Adobe Media Encoder. Go here for details: http://help.adobe.com/en_US/mediaencoder/cs/using/adobemediaencoder_cs5_help.pdf

            1 person found this helpful
            • 3. Re: How to compress videos with camera motion for the web?
              bogiesan-gyyClL Level 3

              Compression for the Web is a dark art, it's al experimentation becuase the results are not only entirely subjective, they are influenced by stuff that's completely out of yopiur control If your'e going up to one of the video sites, the file may be processed after you upload. And you have control over how your visitors see it on their computers.


              I'd start with CBR. The file will be a bit larger. H.264 is fine.


              There are much more informative sites all over the Net dealing specifically with compression of all typs for all types of delivery systems.



              • 4. Re: How to compress videos with camera motion for the web?
                Andy Bay Level 1

                Thanks guys -both answers helpful!


                I'm still open for tips from other power users! What way does your company solve the issue of making camera movements look good even in web compressed videos? A great deal of videos nowadays seem to contain nice and smooth camera motion, so I can't be the only one struggling with such compression issues


                I googled a great deal on the subject, but basically only found tips like "keep the camera stationary". But is that really the only option? Feels like it can't be, since there are so many cool videos with all kinds of camera movements!

                • 5. Re: How to compress videos with camera motion for the web?
                  Kevin-Monahan Adobe Employee

                  The more a camera moves, the more difficult it is to compress for the web. That's just the way it is. When you are making videos for the web there are different rules of thumb to keep in mind over standard production. One of them is to keep the camera as steady as possible.