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  1. Member
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    I am using the passthrough function of my Sony DCR-HC40E camcorder to save my old Hi8 tapes als DV AVI's . I've planned to save them as DV (so no compression) since filesize is no issue any more.

    The problem is that when i play the AVI on the computer (With PowerDVD or VirutalDub), the video has distortion in the bottom. It shows a horizontal line which looks somewhat scrambled.

    If I connect the Hi8 camera directly to my flatscreen TV (Philips 42PF9731 - 1080i) the original video does not show that line.

    How can i avoid this line appearing in my movies? Or - next best - how can i correct it in my digital movies?

    I read something that Hi8 tapes are recorded with two heads and that that creates some distortion in the bottom part of the cideo, but that that is not visible on a normal TV. But then i would guess that everybody should have that same problem and internet would be flooded with people asking questions about it.

    I added an image of one frame. The line is consistent throughout the whole video:
    sanne.png
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  2. Member edDV's Avatar
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    The scrambled line(s) are normal. It is caused by the head switch.

    This occurs outside the normal overscan region of TV sets so is not visible. If you watch on a non overscaned monitor it can become visible. To hide it one would add overlayed borders. Overlay should be used rather than crop to avoid rescale losses.
    http://en.wikipedia.org/wiki/Overscan
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  3. How can i eliminate these lines when I transfer to the computer. I use a Kona card and capture it 10 bit uncompressed. I see the lines under my hi-8 transfers. Is there any deck which does not show these lines? Bor 3/4 inch U-matic, I just read that the BVU 800 series will not show these lines but the VO series does
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  4. Member edDV's Avatar
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    Originally Posted by elandy View Post
    How can i eliminate these lines when I transfer to the computer. I use a Kona card and capture it 10 bit uncompressed. I see the lines under my hi-8 transfers. Is there any deck which does not show these lines? Bor 3/4 inch U-matic, I just read that the BVU 800 series will not show these lines but the VO series does
    All NTSC VTR/VCRs output all active lines. NTSC video (e.g. quad, 1"C, D2) actually output 486 lines. Digital formats (e.g. DV, DVCPro) crop to 480 lines. The Hi8 switching noise occurs inside the 480 lines.

    If you must mask these lines, you do it after capture using a black overlay before encoding to output format. Any resize will degrade quality significantly.


    PS: Just nothiced you are in the Netherlands. In your case both PAL and DV use 576 active lines. The rest is the same.
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  5. Thank you very much. I am not in the Netherlands, what made you think that? I am in Woodstock, NY.
    I have a lot of tapes and they will only be seen on computer systems. I would like not to have to re-save or convert every one with a black border on the bottom. Is there anyway to do this while making the transfer?
    Also just to check that I understand your recommendations, are you saying to import my transfer into an editing program such as FCP and overlay black on the bottom 8 lines of the image and then save it again in whatever final format I need? But will this method produce a black border on the bottom of my images. I plan to distribute them for use on various video players, video games, internet systems, ipads, etc.
    For my work flow , I need to keep them in 10bit uncompressed as well as compressing them later on for various platforms. Is there any way to do this masking while I am transferring them from the tape to the computer? You are also saying that my other option is to resize (also using something like FCP) so the lines are cut off?
    You also say that resizing will seriously degrade the image. Is this true if I start with 10 bit uncompressed, upsize it to eliminate the 8 lines and then output to 10bit uncompressed and only show it on computers, rather than NTSC devices? Thanks very much
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  6. Do you think it would help id of the lines by Up-convert the 525 lines to 720 or 1080. I could also up-convert during the initial transfer with a Kona card.
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  7. Member edDV's Avatar
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    Originally Posted by elandy View Post
    Thank you very much. I am not in the Netherlands, what made you think that? I am in Woodstock, NY.
    The OP was in Netherlands. You jumped in with no location stated.


    Originally Posted by elandy View Post
    I have a lot of tapes and they will only be seen on computer systems. I would like not to have to re-save or convert every one with a black border on the bottom. Is there anyway to do this while making the transfer?
    Still a good idea to capture a clean 704x480i direct capture from the Aja Kona using the built in TBC in the VO if it has one or use the Kona TBC. That will have the headswitch lines visible. Archive that capture.

    Pro NTSC/PAL video was shot with an ~5% safe action border assumption since all CRT TV sets overscan by at least that much. Most HDTV sets overscan 1-2 % all around. The head switch lines won't be seen on a normal CRT but may be partially visible on some LCD/plasma HDTV sets.


    Originally Posted by elandy View Post
    Also just to check that I understand your recommendations, are you saying to import my transfer into an editing program such as FCP and overlay black on the bottom 8 lines of the image and then save it again in whatever final format I need? But will this method produce a black border on the bottom of my images. I plan to distribute them for use on various video players, video games, internet systems, ipads, etc.
    First I would make a masked interlace 704x480i* version. You can just mask ~8 over the bottom, or mask 8 lines top and bottom for a slight letterbox. The active video remains unchanged. I'd export that in 720x480i/29.97 DVD standard as your high quality version.

    Then I would use avisynth to do a high quality deinterlace (could be done with FCP), then crop out the center 680x464 (the action safe area) and horizontally scale that to 624x464 for 4:3 aspect ratio (both h and v divisible by 16). That will be your progressive, uncompressed, 4:3 aspect ratio, square pixel master that can be scaled and encoded to various progressive player specs.


    * The Kona should be able to capture as 704x480i. If you capture 720x480i, there will be 8 black pixels left and right. Those should be cropped off before the horizontal rescale to 624x464.


    Originally Posted by elandy View Post
    For my work flow , I need to keep them in 10bit uncompressed as well as compressing them later on for various platforms. Is there any way to do this masking while I am transferring them from the tape to the computer? You are also saying that my other option is to resize (also using something like FCP) so the lines are cut off?
    You also say that resizing will seriously degrade the image. Is this true if I start with 10 bit uncompressed, upsize it to eliminate the 8 lines and then output to 10bit uncompressed and only show it on computers, rather than NTSC devices? Thanks very much
    The AJA Kona may allow masking during capture. Otherwise do as suggested above. Never upscale the master. If you need an upscaled version, do it from the 624x464 progressive master.
    Last edited by edDV; 1st Feb 2011 at 14:30.
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  8. Member edDV's Avatar
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    Originally Posted by elandy View Post
    Do you think it would help id of the lines by Up-convert the 525 lines to 720 or 1080. I could also up-convert during the initial transfer with a Kona card.
    If you up convert with the Kona card you will be upconverting the head switch lines as well. If the Kona masks and upscales in hardware during capture, you can compare the result to the method above. Never upscale, then downscale. For 624x464 and below use the method above.
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  9. I bought a BVU 950 U-matic deck with installed time code card (used) in good working conditon BUT I still see the headswitching lines when I capture with the Kona card. I thought that the BVu series of U-matic decks was supposed to eliminate the head switching?
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  10. Member edDV's Avatar
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    Originally Posted by elandy View Post
    I bought a BVU 950 U-matic deck with installed time code card (used) in good working conditon BUT I still see the headswitching lines when I capture with the Kona card. I thought that the BVu series of U-matic decks was supposed to eliminate the head switching?
    No, it occurs in the overscan area. U-matic, Betamax, VHS, Hi8 all did this.
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