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What resolution to use......Confused

Discussion in 'Video capturing from analog sources' started by dudds, Sep 13, 2004.

  1. dudds

    dudds Guest

    I have many old home video tapes that I've just decided to try and convert into a digital format (no I have a DVD player). So this weekend I went out and bought what I thought i'd need to do this. My set up is as follows:

    Sony Handycam Video8XR - TR315E PAL
    Belkin Hi-Speed USB 2.0 DVD creator F5U228
    Pinnacle Studio 9

    After alot of heartache I finally got it so I could first capture my video in colour as opposed to black and white, then so that I could actually capture the audio itself.

    So i'm now ready to capture my old video, but I am stuck as to what resolution I need/should use. Now i've tried doing some reading on this over the weekend, but I'm getting rather confused. Since i'm in Australia we use the PAL system which I have read has 625 scan lines, with 576 being displayed. But what is the resolution in the other direction.

    When capturing with Studio9 there are 4 settings, good, better, best and custom. The settings for the first three all use the "PICVideo MJEPG Compressor". The rest of the settings are as follows:
    Good: W320 H240 frame rate 25 60%
    Better: w320 h240 frame rate 25 80%
    Best: w320 h240 frame rate 25 95%

    There is also a custom setting where I chose a width of 720 and a height of 576 with the rest of the settings as shown in best above. I chose 576 as the height because I thought that was what PAL used. The program then chose 720 as the width.

    I then recorded the same portion of video with each of the above settings and output to DVD in studio9.

    Where I seem to be getting confused is that I'm not sure how the capture resolution affects what you see on the TV. For example with the first three tests I did the width and height were the same 320x240 and the output was DVD which I think is 720x576. I would have thought that the video displayed on the TV would have been smaller than the actual screen dimensions. However this was not the case. The only difference between the first three tests was the apparent grainyness of the video which I put down to the amount of compression.

    However the video displayed full screen, not what I thought. Then when I did the final test which I captured at 720x576 the picture looked pretty much the same with one slight difference. The portion of video I tested with had date/time stamp on it. When viewing the first three tests I noticed that half of this was cut off at the bottom of the screen. On the final test however I noticed that it was completely visable and some distance off the bottom of the screen.

    I therefore assume that it does have some affect although not as much as I had imagined. If anyone could be so kind as to shed some light I would appreciate greatly. If it's not already obvious i'm quite new to this.

    Cheers

     
  2. eventual

    eventual Guest

    Doesn't it seem logical that any video that is blown up X4 is going to become grainy? Why would you capture anything at 320x240, unless it's meant to stay that resolution.

    If you capture at 720x576 with the compression settings up there at 6mb/s you will get a nice snapshot of your source. This was not the case?

    So I read up on the F5U228. It claims to have 720x480 capability, and PAL. If that's the case, your captures at 720x576 should look perfect. I think on your first set of captures, you were resizing existing mjpeg data and on the last one you captured at full screen. No resize occured so the computer didn't calculate the frame size and move the stamp for you on that last test.

    Just stick with the full screen captures and get used to adjusting the actual compression ratio to come up with smaller files when you need smaller files.

    You should notice a huge difference in quality if you take the raw-unedited capture and output those as opposed to making a single edit / resize / adjustment.

    This is re-compressing an already compressed image and sends the quality levels spiraling downward. That's what happened the first 3 times, an already compressed file was then doubled in size (ouch) and recompressed (ooof)
     
  3. dudds

    dudds Guest

    Hi Eventual,

    Just tinkering at the moment and have been trying to get everything straight in my head. Too much info coming in at the moment to process. Thanks very much for taking the time to reply to my post. It was most helpful.

    Cheers
     

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