Resizing in VD 1.7.6

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  • losmeme
    Junior Member
    Junior Member
    • Feb 2008
    • 2

    Resizing in VD 1.7.6

    (Title says VD 1.7.6, I am actually using 1.7.7)

    Somewhat new to this, just "playing " around at this point to understand.

    I recorded a movie last night with VD at 640X480, Huffyuv 2.1.1. The final size of that file was 53GB. I then opened it up in VD, sliced off the ends, and then applied the resize filter to 320X240, and then saved to avi. The resulting file was 50GB. Not the file size I was expecting. The files specs for both show their expected 640X480 and 320X240 sizes, so it was resized.)

    Not sure what was going on, I then opened up the original avi file, deleted all but the first 10,000 frames. Saving just the 10K frames at 640X480 gave me a file size of 9GB.

    With the same 10K frames loaded, I applied the resize filter at 320X240, saved to avi and now have a file size of just over 2GB. (This is the file size reduction I was expecting.) I then applied the unsharp mask filter AND resize filter to these same 10k frames, and the file size stayed the same. (I expected this)

    Thinking I missed something, I then reloaded the original 53GB capture file, and applied the 320X240 resize to it. It is writing out now, but it's projected size is still 49 GB.

    Not sure why I am getting the file size reduction on 10K frame clips, but when the same functions are applied to the full file, there doesn't seem to be any reduction.

    All my hardware seems to be performing very well, I get video rendering rates of between 37-39 fps. The original capture had 0 dropped frames.

    What am I missing here?
    Last edited by losmeme; 15 Feb 2008, 05:08 AM. Reason: updating wrong keyed info
  • paglamon
    Lord of Digital Video
    Lord of Digital Video
    • Aug 2005
    • 2126

    #2
    Please select another 10000 frames from that part of the video which has plenty of action or movements. Now test on this fragment and report your findings.

    Not the file size I was expecting.
    Why ? Remember,it is not resizing which directly affects the file size. File size = bitrate(kbps) x time.
    When resizing(to a lower size) the Huffyuv is automatically encoding at a lower bitrate,because it doesn't NEED to encode at any higher bitrate to produce the optimum quality. But if you force any encoder to encode both the files at the same bitrate the output file sizes will be same i.e. a 640x480 video at 1000 kbps will be same in size to a 320x240 video at 1000 kbps.
    Instead of Huffyuv ,select XviD and encode the same 10000 frames at the two different frame sizes(640x480 and 320x240) but at a fixed bitrate of 1000 kbps. Now see for yourself.
    Why Huffyuv is not reducing the bitrate when the whole video is encoded may depend on the type of your video file. Does it contain too many action/fast movement scenes?
    Last edited by paglamon; 15 Feb 2008, 03:42 PM.
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    • losmeme
      Junior Member
      Junior Member
      • Feb 2008
      • 2

      #3
      Paglamon;

      Thanks for that explanation, I remember that now. I did some other tests, and found what I think was the problem.

      I checked the Video Compression, and it was set to RGB. Changed that to HuffYUV (what the original file was compressed to) The Color Depth was set at 24bit RGB, so I set both Decompression and Output to YUY2. (Equal to the original capture.)

      I said I was new to this!

      I am just processing captures through VD to further burn to DVD, so isn't it optimal to have all those settings the same as the capture? Is this what prevents a 2nd recompression or degradation of the image?

      This is my first use of the processor, I have only captured through VD before this.

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      • paglamon
        Lord of Digital Video
        Lord of Digital Video
        • Aug 2005
        • 2126

        #4
        If your final destination is DVD then what is the need for the files to be processed through Virtualdub? Capture in VD with Huffyuv. Then(if you don't need any editing) make DVD compliant mpeg2 files using something like TMPGEnc Plus.
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