3 Replies Latest reply on Dec 12, 2008 8:49 PM by Stan Jones

    Washed Out Colors after Resizing - AVCHD

      I'm fairly new when it comes to video editing and am happy that there is finally AVCHD support in CS4. At least I can now move raw m2ts files quickly into a usable format for the web.

      I successfully exported the file as f4v at a high quality (using the 1080p preset) and was very pleased with the quality of the result. However, due to the fact that the player for this is smaller on my website, the file eats quite a bit of CPU power in order to downsize the video for the player.

      After some research, I discovered that it's best to export the video at the same dimensions as the player you will ultimately display it in. So, I selected the same preset and the only change I made was to resize the video to the correct size for the player (1/3 the original size). The resulting video is very nearly the same file size and indeed is much more CPU friendly when posted online, but the colors are significantly washed out and I feel like I lose quite a bit of detail when compared to the other. Having not changed anything other than the size, I was surprised by this.

      Does anyone have any suggestions as to how to shrink the video (dimensions not file size) and produce the same quality result as my initial attempt? For reference, you can see the two videos I'm referring to at www.brainlessseacreature.com/videos.php - it's Gallows - High Quality and Gallows - Sized Correctly.

      Thanks for your help!
        • 1. Re: Washed Out Colors after Resizing - AVCHD
          Jim_Simon Level 8
          >The resulting video is very nearly the same file size

          That doesn't seem right.
          • 2. Re: Washed Out Colors after Resizing - AVCHD
            Keith_Andrews Level 1
            Pixel resolution does not have as much influence on the final file size as one might think. For example, if you export a video at 320x240 and another at 640x480, the latter will not be twice as large in bytes as the first, in fact they will both be quite close in file size. So that is not something to worry about. What people should always consider when compressing for the web is to make sure the video's resolution is divisible by 16, 8, or 4. If the resolution does not fit this criteria, then it can contribute to choppy playback by the viewers system.

            The high-res version of the "Gallows" video was choppy on my end as well, but that is more than likely due to the fact that the codec used is avc1 and the resolution is 1920x1080.

            You are right about resizing the video to the players dimensions. This will without a doubt help with decoding of the video on the local system, as well as speedup the progressive download playback. I had no problems playing back the "sized-correctly" version from your website.

            As far as color reproduction goes, I looked at the two videos in VLC side by side at roughly the same resolution and I could not see any noticeable difference between the two. Detail was a little softer in the "sized correctly" version, but that is par for the course when resizing video and compressing for the web. The higher resolution version has more pixels to display than the smaller one, hence the difference in detail between the two. The additional data in the smaller version was thrown out when you resized and exported the video.

            Read the following learning guide from Adobe for a little refresher:

            http://www.adobe.com/devnet/flash/articles/video_guide.html
            • 3. Re: Washed Out Colors after Resizing - AVCHD
              Stan Jones Adobe Community Professional & MVP
              Brainless, sorry, can't write your name without laughing.

              If you kept the data rate the same when exporting, the window dimensions will be smaller but the file size just as big. I'm not sure you have that option (don't have CS4), but the file size being the same makes me wonder.