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  1. i saw a lot of examples on the forum about cropping the clip, but i want just to understand:

    in images like that:

    https://forum.videohelp.com/attachments/41225-1492127585/vhs_horizontal_error.png

    and a lot of others i saw on the forum
    there is some garbage/noise at the bottom and seems an usual thing (really?)
    is this an issue of the VCR ? is this an issue from the DIGITIZER device?

    my original footages are PAL from old VHS cameras... (and i use a Samsung DVD+VHS combo device to read them)

    this noise can be CROPPED directly during acquisition using some "special" software able to crop during recording?
    or is necessary to edit the AVI / MP4 acquisition using other softwares? (ffmpeg/megui)

    or i can solve just buying a VCR able to "trim/cut/align" the noise?

    very tahnk you and sorry for the stupid (maybe) question but i'm not converting VHS from 1999... (at time is used a camcorder DV with analog input on teh camera directly connected to a PC)
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  2. Captures & Restoration lollo's Avatar
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    there is some garbage/noise at the bottom and seems an usual thing (really?)
    is this an issue of the VCR ? is this an issue from the DIGITIZER device?
    The "noise" at the bottom of the picture is normal for a VCR capture, and is called head switching noise.

    this noise can be CROPPED directly during acquisition using some "special" software able to crop during recording?
    The frame should be captured at 720x576, which includes the bottom noise. It will be removed (masked) later in post-processing.

    For example in AviSynth:
    Code:
    crop(0,0,0,-10)
    addborders(0,0,0,10)
    or i can solve just buying a VCR able to "trim/cut/align" the noise?
    no

    The defect at the top of 3/4 top of the picture (bad lines) is much more difficult to solve, in particular if it stays for a large number of frames.
    An example here: https://forum.videohelp.com/threads/403553-Restoring-VHS-Tapes-with-Damage-%28White-Ho...-Distortion%29
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  3. Very thank you!
    Originally Posted by lollo View Post

    For example in AviSynth:
    Code:
    crop(0,0,0,-10)
    addborders(0,0,0,10)
    is this procedure loseless? or probably a compressed Mp4 can be show differences on the final output ? (different sizes black block on dark spots or similar things?)
    asking this because i want to be sure to keep maximum quality to customers
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  4. Captures & Restoration lollo's Avatar
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    The procedure done in AviSynth on YUV 4:2:2 lossless capture is lossless. If you compress to h264/h265 there is not a difference in quality if you have or not head switchig noise, but not having it avoid the usage of additional bitrate to compress the noise (or, at the same bitrate, not having the head switching noise produces marginal "better" quality)

    If your captured file is already h264 compressed, you can try to crop and adjust the PAR to avoid a decoding/coding for masking the head switching noise.
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  5. All VCRs will give some head switching noise. Some more than others. You never saw that noise when watching on a CRT TV because those TVs never showed you the outer ~5 percent of the frame:

    https://en.wikipedia.org/wiki/Overscan

    As was pointed out by lollo, you can crop away that portion of the frame after capture. Whether you want to replace those lines depends on what you intend to do with the video afterward. For example, PAL DVDs require a full 576 line frame (480 lines for NTSC) so you must replace those lines. If your final delivery is an MP4 file you don't need to.

    You will typically have about 10 black columns at the left and right edges of the frame too. You may want to crop those away too, depending on the target usage.

    These are some reason why the best procedure is to capture YUY2 (or other YUV 4:2:2) video and compress with a fast lossless codec. Edit/filter that lossless video and output to your intended format.
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  6. thank you very much, and another question:

    the "distortion" showed on the image has a "technical" name?
    there are existent plugins/algorithms/tools that can "align" the video ? ( these clips are coming from a VHS-C camcorder and are all showing these "waves" ..and are now on a standard VHS tapes)
    Image Attached Thumbnails Click image for larger version

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  7. Captures & Restoration lollo's Avatar
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    the "distortion" showed on the image has a "technical" name?
    skew errors, horizontal wiggle, time base errors, flagging. Other users may help you with a better technical definition.
    http://www.avartifactatlas.com/artifacts/skew_error.html

    Not really fixable in post-processing, you need a lineTBC in your workflow. If the defect has been "baked" in the vhs recording at the time of its creation from the VHS-C transfer, is there forever.
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  8. very thank you Lollo!
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  9. [QUOTE=lollo;2687435]
    If the defect has been "baked" in the vhs recording at the time of its creation from the VHS-C transfer, is there forever.
    I was thinking the same.. no software are able to "unskew"... BUT (after a lot of experiments) i bought a Philips VR1000 that with the integrated TBC can restore the vertical alignment (very well) also on tapes recorded from VHS-C with a bad rotating drum
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  10. Captures & Restoration lollo's Avatar
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    i bought a Philips VR1000 that with the integrated TBC can restore the vertical alignment (very well) also on tapes recorded from VHS-C with a bad rotating drum
    Excellent! A proper vertical alignment is (one of) the purpose of a lineTBC correction
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