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  1. Can someone help identify/fix this. I'm trying to eliminate the small horizontal lines. The analyzer in MeGUI is calling it: "Hybrid film/interlaced. Mostly film", but nothing I've tried works at getting rid the lines. I attached a 30 second clip. If anyone can help I would appreciate it. Thanks.

    30 second clip
    http://www.mediafire.com/file/34sd9bz1f7ct2lf/sample_clip.avi/file
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  2. Member DB83's Avatar
    Join Date
    Jul 2007
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    United Kingdom
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    I'll ask the obvious.


    1. Do you get this artefact with all vhs tapes or just this one ?
    2. What capture device are you using ?
    3. Are the lines still there if you play the tape direct to a tv ?
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  3. It's a film source but I can't make any sense of the horizontal lines. At first I thought it had bee resized vertically but the two fields are intact and it inverse telecines cleanly (aside from the lines). Is this straight from the DV device? Has it been filtered or re-encoded?

    This reduces the lines a bit, at the cost of sharpness:

    Code:
    AviSource("sample_clip.avi") 
    TFM()
    TDecimate()
    Blur(0.0, 1.0)
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  4. Originally Posted by DB83 View Post
    I'll ask the obvious.


    1. Do you get this artefact with all vhs tapes or just this one ?
    2. What capture device are you using ?
    3. Are the lines still there if you play the tape direct to a tv ?
    No, it's just this tape. VCR (S-Video) - Sony Handycam (S-Video) - WinDV. The lines don't show up on my TV (VCR connected with RCA cables). Thought maybe it was the VCR and did another capture using a few different VCR's. I tied S-Video & RCA cables and the lines show up in the capture with both types of cables.
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  5. Originally Posted by jagabo View Post
    It's a film source but I can't make any sense of the horizontal lines. At first I thought it had bee resized vertically but the two fields are intact and it inverse telecines cleanly (aside from the lines). Is this straight from the DV device? Has it been filtered or re-encoded?

    This reduces the lines a bit, at the cost of sharpness:

    Code:
    AviSource("sample_clip.avi") 
    TFM()
    TDecimate()
    Blur(0.0, 1.0)
    The clip in the link was cut with VirtualDub - direct stream copy.
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  6. Since it is analog video which is being digitized to DV in your camcorder, there is the possibility of ground loops between the the VCR, the digitizing camcorder, and the computer. The ground loop may not exist between the camcorder and the TV set and that's why everything looks OK there.

    The usual troubleshooting for ground loops is to have every single thing plugged into the same power strip, and to disconnect ALL other items that have nothing to do with the capture. This is especially true for any cable TV that might be going into the VCR because that is a very common way to introduce ground loops.
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  7. Member DB83's Avatar
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    United Kingdom
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    +1


    When I first saw them, electrical interference immediately came to mind. Just wanted to eliminate any other possibility (I did not check that this was DV but even then the Q.s were still relevant)
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  8. Originally Posted by DB83 View Post
    (I did not check that this was DV but even then the Q.s were still relevant)
    In his second post he describes his capture setup as:
    VCR (S-Video) - Sony Handycam (S-Video) - WinDV
    DV is the result of the digitizing, but the video starts out as analog and goes from a VHS or 8mm VCR to a camcorder that is doing the actual digitizing to DV.

    I have an extremely complicated setup where I run signals from my home theater upstairs to my office. Because of the lengths of that connection, I initially had all sorts of ground loop issues and had to spend several days, over a period of months, to track down and eliminate all the issues. I "went to school" on ground loops and found literally dozens of different ways they can happen and dozens of different ways to eliminate them.

    The main piece of advice from that long ago effort is to remove ALL connections not needed; have everything plugged into the same plug in the wall; keep connections short; and if all else fails, start using isolation transformers. I have an isolation transformer for the mains, and various baluns for the analog video and also the audio.

    Remember, the ground loop can be created both from the mains power as well as all the signal connections. Even if the current on the signal connections is tiny (which it is for audio and video), the ground connections can still carry lots of current. That current creates a voltage when it travels through any conductor, and it is that voltage that ends up being converted to a signal that appears in the audio as some sort of hum, or in the video as some sort of constant artifact.

    I will repeat: the cable TV connection almost always introduces a problem and the OP should disconnect that when doing captures, or find balun designed for cable TV and install that.

    The worst ground loop I ever saw was so bad that it blew out several pieces of equipment. It happened after I moved back into our house after it had been remodeled. I noticed that my old CRT monitor (this was 1995) was waving back and forth, but only sometimes. To cut to the chase, I finally tracked it down to a junction box in the kitchen where the electrician had wired together all the neutrals in that box. The problem was they were not only from different circuits, but they were from circuits that were on opposite phases. One of those circuits fed my office and the other fed the kitchen lights. Those lights consisted of 15 50W track lights, plus a few 75W can lights. Those induced an out-of-phase voltage into my office neutral. What's worse, this was a quarter century ago, before CF or LED bulbs, so the kitchen lights were all incandescent bulbs. When they turned on, there was a massive inrush current. Even though I had surge suppressors in the office, they were the simple varistor suppressors which are 100% useless devices. The surges blew out my fax machine and my answering machine. I was able to fix both of them (rebuild power supply), and I rewired the junction box myself and told the clueless electrician about it. He claimed his work met code and could not understand what a horrible thing he had done.

    A quarter of a century later, and everything has been running fine ever since.

    I have other stories to tell about how my various baluns have let me run long wires in auditoriums and other venues without having any ground loops.
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  9. I did think about some type of ground/electrical interference. I think it's the tape itself. I only have this problem with this particular tape. I'm not using a power strip, don't have cable TV, and use the Handycam w/battery (also tried with the power adapter). Out of curiosity, I'll try re-capturing it with an ATI USB 600
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  10. Originally Posted by JayD View Post
    I only have this problem with this particular tape.
    Then the problem is that tape.
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  11. Originally Posted by JayD View Post
    I did think about some type of ground/electrical interference. I think it's the tape itself. I only have this problem with this particular tape. I'm not using a power strip, don't have cable TV, and use the Handycam w/battery (also tried with the power adapter). Out of curiosity, I'll try re-capturing it with an ATI USB 600
    Your statement is confusing. You previously said:

    The lines don't show up on my TV (VCR connected with RCA cables).
    If the problem is on the tape, then it should show up on your TV as well.
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  12. I was playing around with resharpening the clip after blurring it (as in post #3). At some point I added Santiag() to reduce some aliasing created by the sharpening. I unexpectedly found that Santiag() also reduced the remaining horizontal lines. So I removed the Blur() and applied just Santiag(). I found that two passes with Santiag() almost completely eliminated the lines and slightly sharpens the picture.

    Code:
    AviSource("sample_clip.avi") 
    TFM()
    TDecimate()
    Santiag(3,3)
    Santiag(3,3)
    It still needs some other cleanup but this is a good start.
    Image Attached Files
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  13. Originally Posted by johnmeyer View Post
    Originally Posted by JayD View Post
    I did think about some type of ground/electrical interference. I think it's the tape itself. I only have this problem with this particular tape. I'm not using a power strip, don't have cable TV, and use the Handycam w/battery (also tried with the power adapter). Out of curiosity, I'll try re-capturing it with an ATI USB 600
    Your statement is confusing. You previously said:

    The lines don't show up on my TV (VCR connected with RCA cables).
    If the problem is on the tape, then it should show up on your TV as well.
    I don't have an answer. It's weird. No idea why the lines don't show up on my TV. Like I said, it is just this tape that I have this type of problem with.
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  14. Originally Posted by jagabo View Post
    I was playing around with resharpening the clip after blurring it (as in post #3). At some point I added Santiag() to reduce some aliasing created by the sharpening. I unexpectedly found that Santiag() also reduced the remaining horizontal lines. So I removed the Blur() and applied just Santiag(). I found that two passes with Santiag() almost completely eliminated the lines and slightly sharpens the picture.

    Code:
    AviSource("sample_clip.avi") 
    TFM()
    TDecimate()
    Santiag(3,3)
    Santiag(3,3)
    It still needs some other cleanup but this is a good start.
    That looks pretty good. It's a starting point. Thanks.
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  15. Member
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    Jagabo, I'm continually amazed at what you can do. Very inspirational.
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