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  1. Member
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    I did a test to compare a pro-sumer SVHS to a bog standard VHS and it seems the SVHS is only very slightly sharper. Chroma is still pretty bad. Is that normal?

    VHS:
    Image
    [Attachment 48197 - Click to enlarge]


    SVHS:
    Image
    [Attachment 48198 - Click to enlarge]


    I have a test card image that I can export direct to capture device for very clean output for the recorders.

    This is the workflow:

    SVHS:
    1. From photoshop,"Export Blackmagic Image.." to the Blackmagic Intensity Shuttle
    2. s-video cable from Blackmagic to Panasonic NV-HS930 (SVHS) in
    3. Record to S-VHS tape
    4. Then playback via s-video to Blackmagic Intensity Shuttle for capturing at uncompressed.

    VHS:
    1. From photoshop,"Export Blackmagic Image.." to the Blackmagic Intensity Shuttle
    2. composite cable from Blackmagic to Sharp VC-MH704 (VHS) in
    3. Record onto VHS tape
    4. Then playback via composite to Blackmagic Intensity Shuttle for capturing at uncompressed.

    Compared to a fairly high-end svhs recorder to a bog standard vhs, there doesnt seem much difference. And the svhs has rainbowing which isnt good.

    Is the SVHS player malfunctioning??

    Attached screenshots and huffy compressed video for you guys to view.
    Image Attached Files
    Last edited by Bassquake; 25th Feb 2019 at 08:34. Reason: Minor editing.
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  2. Yes, SVHS has the same chroma resolution as VHS. Only the luma resolution is improved -- easily seen in your sample images. And keeping the chroma and luma separate should prevent dot crawl and rainbow artifacts. Your SVHS cap also shows much better horizontal time base (less side-to-side jiggle of all those vertical edges).
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    Thanks jagabo. Although you say "keeping the chroma and luma separate should prevent dot crawl and rainbow artifacts", there's pretty significant rainbowing on the middle set of lines and none on the vhs one!

    Dont know how they could justify the price jump back in the day for marginal improvement!
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  4. aBigMeanie aedipuss's Avatar
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    vhs 240 lines of resolution. svhs 420 lines of resolution. ntsc tv analog broadcast tv 330 lines of resolution. svhs was quite an improvement at the time. if only they could have bumped up the chrominance level...
    --
    "a lot of people are better dead" - prisoner KSC2-303
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  5. Member dellsam34's Avatar
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    I get the rainbow effect on VHS not S-VHS, Either your BM device is doing something wrong or the quality of the S-VHS tape is no good, If you see the rainbow effect in the live feed then the best way to do this test is through a good quality HDMI to S-Video/Composite adapter using a blu-ray or a HD media player as a source.
    The quality depends on a lot of factors, The age of electronic components on the composite and S-Video circuit boards, The quality of the tapes, The quality of cables ...etc
    Also you get faithful results using the same VCR in VHS and S-VHS modes.
    Last edited by dellsam34; 25th Feb 2019 at 09:43.
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    Originally Posted by Bassquake View Post
    there's pretty significant rainbowing on the middle set of lines and none on the vhs one!
    You can't judge the quality of an entire standard by the performance of one vintage tape deck. Your Panasonic has an obvious problem with that particular range of frequencies. This could be due to a design flaw in the model, or more likely, aging/misadjustment of circuit board components.
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  7. Originally Posted by Bassquake View Post
    Thanks jagabo. Although you say "keeping the chroma and luma separate should prevent dot crawl and rainbow artifacts", there's pretty significant rainbowing on the middle set of lines and none on the vhs one!
    The lack of dot crawl and rainbow artifacts on your composite VHS cap indicates your capture device has a 3d comb filter. That can work very well on still parts of the picture (all of your video) but isn't as effective on moving parts of the picture. That comb filter will not be used the the s-video input as it shouldn't have those defects (ie crosstalk between the luma and chroma on a composite signal). I'm not sure why your s-video pattern has all that rainbowing. Was the tape recorded from a composite source rather than an s-video source? That might explain it.
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    Was the tape recorded from a composite source rather than an s-video source?
    Nope, was recorded from a pure s-video signal from the Blackmagic. I checked the output from the blackmagic to a tv and it looks excellent so its not the cables. The playback from the SVHS player is quite a drop in quality.

    The tape used in the SVHS player is a Konica SE-60 SVHS tape. Only been recorded onto twice.

    Edit: Image looks great when viewing live signal through SVHS player, just not the recording.
    Last edited by Bassquake; 25th Feb 2019 at 12:20.
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  9. Originally Posted by Bassquake View Post
    Was the tape recorded from a composite source rather than an s-video source?
    Nope, was recorded from a pure s-video signal from the Blackmagic. I checked the output from the blackmagic to a tv and it looks excellent so its not the cables. The playback from the SVHS player is quite a drop in quality.

    The tape used in the SVHS player is a Konica SE-60 SVHS tape. Only been recorded onto twice.
    If you view the s-video output from the SVHS deck on a TV do you see the same rainbowing? Maybe somebody who knows SVHS better than I do can explain it.
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  10. Member dellsam34's Avatar
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    Originally Posted by Bassquake View Post
    The tape used in the SVHS player is a Konica SE-60 SVHS tape. Only been recorded onto twice.

    Edit: Image looks great when viewing live signal through SVHS player, just not the recording.
    Try a good quality tape, I bet the rainbow effect will not be there, I get the same effect when recording S-VHS ET on poor quality tapes.
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    If you view the s-video output from the SVHS deck on a TV do you see the same rainbowing?
    If you mean playing the video on the svhs player then yes, the rainbow effect is still there. The live passthrough looks clean and no artifacts.

    Try a good quality tape
    I will give it a go. Might take a while to report back as I dont have another one on hand.
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    @dellsam34: Im not using SVHS ET by the way. Im using a standard Konica SVHS tape.
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  13. Member dellsam34's Avatar
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    Originally Posted by Bassquake View Post
    @dellsam34: Im not using SVHS ET by the way. Im using a standard Konica SVHS tape.
    That's my point, S-VHS ET is recording a S-VHS signal into a VHS tape = low quality S-VHS tape. I know the VCR does some tweaking to the signal but the point is that's what you get from tapes with low density particles such as low quality S-VHS tapes (in your case) or just plain VHS tapes (in my case) for such high band signal.
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  14. I imagine a poor s-video cable could allow the luma signal to leak into the chroma.
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  15. Member dellsam34's Avatar
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    Here is a sample of a S-VHS video recorded on a high quality tape, A raw version is available here without YouTube compression. Unfortunately I don't have a VHS version to compare to.

    Also I use something like this as a cable.
    Last edited by dellsam34; 25th Feb 2019 at 13:33.
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    @23dellsam34: Cool cheers. That looks a lot cleaner than my recordings. Maybe my player isnt working properly.

    I imagine a poor s-video cable could allow the luma signal to leak into the chroma.
    Looking at the live passthrough it looks nice and clean though, no rainbows. Tried swapping cables too.
    Last edited by Bassquake; 25th Feb 2019 at 13:47.
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    I noticed the VHS tape which had the test pattern recorded via composite, is better quality being played from the VHS player than the SVHS deck. I thought the SVHS player would keep the quality?

    Attached screencap of it. Compared side by side to the composite VHS.

    SVHS seems to have crosshatching noise (see cyan colour block) too.
    Image Attached Thumbnails Click image for larger version

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  18. Member Cornucopia's Avatar
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    @Bassquake,
    In looking at your 1st post, you aren't fully comparing apples to oranges. If you want a true indicator of whether you are getting a good recording from that deck, or at least whether the S- portion is better than the standard VHS portion, it would make more sense to make 4 recordings on the S-VHS deck:
    • Out via Composite, Record in S-VHS mode
    • Out via Composite, Record in VHS mode
    • Out via S-Video, Record in S-VHS mode
    • Out via S-video, Record in VHS mode
    Then you compare with the VHS deck (which I assume you are using that same composite for its one recording option).

    Also, you may be getting some comparison fudging by the fact that you are playing back via different decks, so you would also want to try playing each of those 5 recordings above through both the S-VHS deck and the standard VHS (knowing that the S- mode recordings may not playback properly or at all in the VHS deck if it doesn't have S- mode playback support). That way you can rule out what might be occurring from playback itself.

    ISOLATE the steps so you know what each element is contributing to the equation.

    Scott
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  19. Member dellsam34's Avatar
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    Using two VCR's is definitely not going to give you an accurate results.
    Like Cornucopia said, Use the same VCR and make two recordings from S-Video one in S-VHS on a good quality S-VHS tape and one in VHS mode on a good quality VHS tape, This is to test the medium recording capabilities.
    And two more recordings from composite, again one in S-VHS and one in VHS modes and this to compare the VCR processing capabilities, Just to see how the VCR handles the composite signal on both formats.

    From best to worst it should go like this:

    S-Video-S-VHS --> S-Video-VHS --> Composite-S-Video --> Composite-VHS
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  20. Originally Posted by Bassquake View Post
    I noticed the VHS tape which had the test pattern recorded via composite, is better quality being played from the VHS player than the SVHS deck. I thought the SVHS player would keep the quality?

    Attached screencap of it. Compared side by side to the composite VHS.

    SVHS seems to have crosshatching noise (see cyan colour block) too.
    It looks to me like the VHS deck has a noise reduction circuit. Along with with the noise it will reduce small low contrast detail. The SVHS deck may indeed have some other noise source. It's hard to find one in perfect working condition now since they haven't been made in many years.
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    Originally Posted by Bassquake View Post
    I noticed the VHS tape which had the test pattern recorded via composite, is better quality being played from the VHS player than the SVHS deck. I thought the SVHS player would keep the quality?
    Have these machines been serviced and calibrated to specification? If not, you aren't getting a fair representation of the signal standards or quality of these models. You are just seeing the condition of this one particular Panasonic deck.
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  22. Member Cornucopia's Avatar
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    BingPot!

    Scott
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    In a well-calibrated and maintained system, SVHS should exceed VHS in quality. There should be no difference in quality between a VHS tape played back on either a VHS or SVHS deck *unless* the SVHS deck contains a good comb filter to convert the composite signal to Y/C. If your SVHS looks worse than your VHS, then this may be because:
    - the heads on the SVHS deck need cleaning or are worn or mistracked;
    - the transport mechanism in the SVHS deck needs adjusting;
    - the Y/C filter or composite circuitry are busted or low quality;
    - somewhere along your video capture chain, a component you’re using isn’t doing the trick - moire patterns from the A/D conversion, etc.

    I recorded the same test signal from the same input source in both VHS and S-VHS signals (using the same S-VHS blank tape). The difference is immediately noticeable. See attachments.
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    Last edited by CheerfulRam; 14th May 2021 at 13:15. Reason: Typo
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  24. Old thread, but since it popped up again, it might be worth noting the OP was using a Panasonic NV-HS930 vcr. This model tends to have more issues than the similar NV-HS800 series in terms of video processing, making it less than ideal for some capture devices. Such a dramatic fail of SVHS mode in this case probably indicates a major defect, but it could also be a conflict between this model VCR and the capture system. While Panasonic NV-HS900s are technically "higher/better" models than the NV-HS800s, for various reasons the 800 series is preferred as more predictable/reliable for capture purposes (better balanced performance in their TBC/DNR processing circuits).
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    There should be no difference in quality between a VHS tape played back on either a VHS or SVHS deck *unless* the SVHS deck contains a good comb filter to convert the composite signal to Y/C.
    I have probably misunderstood the statement, but the recorded signal in a VHS is Y/C, not composite!
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  26. Member dellsam34's Avatar
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    It's a 3 decades long confusion, S-VHS is interchangeably used for referring to S-Video socket and vise versa, The other confusion is that VHS is namely a composite format when in fact it is not, LaserDisc is, despite of its superior quality over VHS.
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  27. Yeah vhs is not composite on the tape, chroma and luma are separate (with a very slight overlap on standard vhs). Maybe they were talking about recording from a composite input?. There is an internal comb filter on the chroma output but that's mainly for reducing crosstalk between different video tracks and other noise, it doesn't operate on a combined y+c signal.

    There is clearly a notable difference between the two images in the original post, the SVHS one has a lot more resolution. The chroma stuff over the horizontal bands on a tape recorded from S-Video input and played back through s-video out is a bit odd though (there is a bit of rainbowing on the VHS one too if you look close). Ideally there would be a comparison to a direct capture from the blackmagic output to see that the source looks as expected.

    The first 8/9 in the model number indicates more where the model is in a lineup than when it came out. The 860/960 (same video processing as far as I know, difference is in other features) seem to be the most coveted ones of those later Panasonic PAL models. Their naming was not very consistent (e.g nv-hs850 and 950 are from different lineups and differ substantially) so I don't think it's a good indicator of whether a model is worth looking into or not, it's more the specific model.
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  28. Originally Posted by oln View Post
    The first 8/9 in the model number indicates more where the model is in a lineup than when it came out. The 860/960 (same video processing as far as I know, difference is in other features) seem to be the most coveted ones of those later Panasonic PAL models. Their naming was not very consistent (e.g nv-hs850 and 950 are from different lineups and differ substantially) so I don't think it's a good indicator of whether a model is worth looking into or not, it's more the specific model.
    Its kind of a grey area with a lot of "it depends" attached to it. The NV-HS900 series is not "bad", per se, but there were a couple of exhaustive capture comparison threads some years ago indicating Panasonic slightly modified the video processing in some 900s vs the best of the 800s. Depending on the specific capture device and workflow, certain 900s were more prone to problematic captures (ringing, excessive edge enhancement, etc). Its a subtle difference when they're used directly as VCRs for TV playback (as intended), but some owners were vocally disappointed in their capture results. Compared to a similar "ordinary" Panasonic model from the same era without TBC/DNR, a 900 series would almost certainly still be preferable despite some added potential for video artifacts.
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  29. Yeah, I have the NV-HS870 which is mostly the same as the 930 but with only DNR and no TBC, and I've found it to sharpen a bit much, and also has the same weirdness with dropout compensated lines that some JVCs have where they don't line up well with previous lines no matter what (I think they use a similar main video IC to the one used in JVCs decks from the time). They use a more conventional video decoding chain rather than the special digital process stuff of the 860/960, 850 and 950 (and related models in other systems) used.
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