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  1. Member
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    I live in the PAL zone. Recently, I purchased an unofficial RGB SCART cable for a video game console, which is not even shielded and thus gets interference easily.

    I also have a RGB-compatible DVD recorder and made an attempt at recording gameplay with it. It converts the RGB signal to YUV and then it can be recorded in MPEG2.
    However, this device causes a lot of latency and it's very difficult to play while looking at the output of the DVD. Therefore, I had to find a way to duplicate the picture so that I could see it with no latency while it's being recorded by the DVD device. I managed to find it, but at the cost of more interference.


    I guess this is kind of an uncommon case: the source is not either composite or S-Video, but still analog. In fact, the quality of the RGB source is pretty good, the capture is encoded with the highest standard bitrate offered by my device (~8000Kbps), and the interference looks quite periodical to me. That's why I think there should be some way to fight this interference efficiently on software (it would then be an easier solution than looking for higher quality cables). However, I'm a bit lost regarding the way this artifact should be treated. I've had no success with any AviSynth filters I had used before, and since it is PAL video that originates from RGB I feel like many filters were not designed for this situation.

    Can you lend me a hand? Thank you very much.

    Video sample is attached.
    Image Attached Files
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  2. VGA splitter should work OK.
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  3. I suspect the console is generating a composite signal and the RGB output is created from that -- with no comb filtering to remove the chroma subcarrier from the luma channel. Here's a simple way to nearly eliminate it while only losing a little sharpness and detail:

    Code:
    Mpeg2Source(VTS_01_2.demuxed.sample.d2v", CPU2="ooooxx", Info=3) 
    Spline36Resize(width/2, height).Spline36Resize(width,height)
    The output will be interlaced video, just like the source. You can follow that up with more traditional denoising and a smart bob.

    A better way, uses a mask to overlay the blurred image over the original only where there are colors:

    Code:
    #################################################
    # absolute value of chroma after UtoY() or VtoY()
    #################################################
    
    function cABS(clip c)
    {
        Overlay(c.ColorYUV(off_y=-128), c.Invert().ColorYUV(off_y=-127), mode="add")
    }
    
    #################################################
    
    Mpeg2Source("VTS_01_2.demuxed.sample.d2v", CPU2="ooooxx", Info=3) 
    
    filtered = Spline36Resize(width/2, height).Spline36Resize(width, height)
    
    # Create a mask of the more saturated colors, adjust mt_binarize value to suit
    cmask = Overlay(UtoY().cABS(), VtoY().cABS(), mode="add").mt_binarize(15).Spline36Resize(last.width, last.height)
    
    # replace pixels of the source with the filtered version, only were colors were saturated
    Overlay(last, filtered, mask=cmask)
    Colored text (or other small objects) over a colored background will still get blurred but greyscale text will remain sharp. From there you can denoise, qtgmc, whatever.
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    Last edited by jagabo; 27th Jun 2017 at 21:46. Reason: added clip
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    Originally Posted by pandy View Post
    VGA splitter should work OK.
    I would then need three VGA to SCART adapters

    Originally Posted by jagabo View Post

    A better way, uses a mask to overlay the blurred image over the original only where there are colors:

    Code:
    #################################################
    # absolute value of chroma after UtoY() or VtoY()
    #################################################
    
    function cABS(clip c)
    {
        Overlay(c.ColorYUV(off_y=-128), c.Invert().ColorYUV(off_y=-127), mode="add")
    }
    
    #################################################
    
    Mpeg2Source("VTS_01_2.demuxed.sample.d2v", CPU2="ooooxx", Info=3) 
    
    filtered = Spline36Resize(width/2, height).Spline36Resize(width, height)
    
    # Create a mask of the more saturated colors, adjust mt_binarize value to suit
    cmask = Overlay(UtoY().cABS(), VtoY().cABS(), mode="add").mt_binarize(15).Spline36Resize(last.width, last.height)
    
    # replace pixels of the source with the filtered version, only were colors were saturated
    Overlay(last, filtered, mask=cmask)
    Colored text (or other small objects) over a colored background will still get blurred but greyscale text will remain sharp. From there you can denoise, qtgmc, whatever.
    The detail loss seems very slight to me. Looks like a very good solution!

    I guess it won't make any harm to change the Spline36Resize for Spline64Resize.
    What bobber did you use?

    Originally Posted by jagabo View Post
    I suspect the console is generating a composite signal and the RGB output is created from that -- with no comb filtering to remove the chroma subcarrier from the luma channel.
    I'm not sure of that. Previously, I made a comparison between the RGB and composite outputs of the console and RGB's quality was much superior, both in detail and cleanness. What I'm sure of is that my DVD recorder is likely to generate interference with video inputs, as it already happened to me before. In this case, the interference is less intense when the RGB output of the console is plugged directly to the recorder, instead of using the SCART splitter solution I found.
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  5. Originally Posted by magiblot View Post
    I guess it won't make any harm to change the Spline36Resize for Spline64Resize.
    No problem.

    Originally Posted by magiblot View Post
    What bobber did you use?
    I followed the earlier script with
    Code:
    QTGMC(preset="fast", EZDenoise=2.0)
    TTempSmooth()
    Santiag()
    aWarpSharp(depth=5)
    Sharpen(0.5)
    Obviously, adjust that to get what you want.
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  6. Originally Posted by magiblot View Post
    What I'm sure of is that my DVD recorder is likely to generate interference with video inputs
    While there is a little noise the main problem is the chroma subcarrier. PAL dot crawl artifacts show a pattern that repeats every four frames (which is one reason why the NTSC dot crawl removers don't work with PAL -- the NTSC pattern repeats every 2 frames). If you use SelectEvery(4) to view the video you'll see the pattern stands still. And there is no pattern in greyscale parts of the picture.

    A native RGB or even s-video signal would not have this problem. So somewhere the chroma subcarrier is leaking through.
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  7. Originally Posted by magiblot View Post
    Originally Posted by pandy View Post
    VGA splitter should work OK.
    I would then need three VGA to SCART adapters
    You can use VGA to BNC cable (should be cheap or even for free) and BNC to SCART cable - i assume this may be easier if you are not "soldering" type of guy.
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  8. Member
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    Originally Posted by jagabo View Post
    While there is a little noise the main problem is the chroma subcarrier. PAL dot crawl artifacts show a pattern that repeats every four frames (which is one reason why the NTSC dot crawl removers don't work with PAL -- the NTSC pattern repeats every 2 frames). If you use SelectEvery(4) to view the video you'll see the pattern stands still. And there is no pattern in greyscale parts of the picture.

    A native RGB or even s-video signal would not have this problem. So somewhere the chroma subcarrier is leaking through.
    I would say the console generates a native RGB signal. A reason for this is that the NTSC version, which was designed without RGB output, can be modded to obtain RGB from some chip. It's common for consoles to "think" in RGB first.

    However I have to admit that even when I connect it directly to the TV some interference can already be seen. I used to think it was just because of the cheap cable, but now I realise that composite video is used for sync. That's probably where it all begins.

    It seems that PAL dot crawl is barely supported by AviSynth filters. I've found none working with my source.

    Originally Posted by pandy View Post
    Originally Posted by magiblot View Post
    Originally Posted by pandy View Post
    VGA splitter should work OK.
    I would then need three VGA to SCART adapters
    You can use VGA to BNC cable (should be cheap or even for free) and BNC to SCART cable - i assume this may be easier if you are not "soldering" type of guy.
    I'm sorry, but I think you are in a misunderstanding. I finally found a splitting solution, as I said in the first post. Thanks for trying to help.



    This is a very clumsy solution, but it does the job if you don't have a lot of material to make anything better.

    With another multi SCART adapter and a pair of male-to-male SCART cables I think it would be possible to have RGB output for the TV.
    Last edited by magiblot; 28th Jun 2017 at 16:12.
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  9. Originally Posted by magiblot View Post
    It seems that PAL dot crawl is barely supported by AviSynth filters. I've found none working with my source.
    As noted earlier, PAL dot crawl has a pattern that repeats every 4 frames, whereas NTSC dot crawl's pattern repeats every 2 frames. You can use an NTSC filter like CheckMate() like this with PAL video:

    Code:
    even = SelectEven().CheckMate(thr=10, max=20, tthr2=10)
    odd = SelectOdd().CheckMate(thr=10, max=20, tthr2=10)
    Interleave(even,odd)
    It's not optimal because the blending now comes from two frames away rather than adjacent frames (and Checkmate generally isn't good with animation). But it basically works for non-moving parts of the image.
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  10. Originally Posted by magiblot View Post

    Originally Posted by pandy View Post
    Originally Posted by magiblot View Post
    Originally Posted by pandy View Post
    VGA splitter should work OK.
    I would then need three VGA to SCART adapters
    You can use VGA to BNC cable (should be cheap or even for free) and BNC to SCART cable - i assume this may be easier if you are not "soldering" type of guy.
    I'm sorry, but I think you are in a misunderstanding. I finally found a splitting solution, as I said in the first post. Thanks for trying to help..
    Well... active VGA splitter will provide proper signal conditioning - passive splitters will not separate you from typical problems - too low impedance - too many receivers connected to 75ohm output - this may reduce signal level, reduce bandwidth, introduce some phase distortions in analog signal and in very bad case scenario it may damage damage signal source (usually not the case but theoretically possible in badly designed HW).

    In your connection diagram - double load may be present ot CVBS line - this ma reduce level of signal - important for synchronization pulses - some devices can be more tolerant some not, additionally to insufficient level, SNR margin may be too low from SYNC stripper perspective (will lead to increased jitter and other problems).
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  11. Member Skiller's Avatar
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    The interference is indeed caused by the Composite video signal (which is only used for sync here, like all standard RGB-Scart cables do it) leaking into the RGB wires.

    A well shielded cable can cure this but the best way to eliminate it in the first place is not to use Composite video for sync but so called "CSYNC", which is basically a Composite video signal but without any video content (just H/V sync pulses). This would require a special cable that connects to a CSYNC output on your console – provided it has one.

    Maybe have a look at retrogamingcables.co.uk, they have special handmade cables for consoles which offer superb picture quality and features like CSYNC.

    Or get a decent S-Video cable; it would still look pretty good and is much easier to handle than RGB.
    Last edited by Skiller; 29th Jun 2017 at 09:11.
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    Originally Posted by Skiller View Post
    The interference is indeed caused by the Composite video signal (which is only used for sync here, like all standard RGB-Scart cables do it) leaking into the RGB wires.

    A well shielded cable can cure this but the best way to eliminate it in the first place is not to use Composite video for sync but so called "CSYNC", which is basically a Composite video signal but without any video content (just H/V sync pulses). This would require a special cable that connects to a CSYNC output on your console – provided it has one.

    Maybe have a look at retrogamingcables.co.uk, they have special handmade cables for consoles which offer superb picture quality and features like CSYNC.

    Or get a decent S-Video cable; it would still look pretty good and is much easier to handle than RGB.
    Unfortunately, there's a drawback for almost each of the possible upgrades: the console does not output composite sync (CSYNC) (which I have seen before, in a VGA to SCART converter for a PC), neither S-Video (and S-Video is not so common in my region: my DVD recorder does not have a S-Video input, neither do many TVs, and S-Video to SCART conversion does not usually work).

    I have seen that page before and it looks promising. However, I don't want to spend more money on any cables for a while. In addition, they did a very ugly thing some years ago:

    https://www.retrogamingcables.co.uk/nintendo/nes/nintendo-nes-av-composite-audio-video...e-tv-lead-cord

    https://www.youtube.com/watch?v=-xCsU_Ss9FY

    That product is obviously not going to provide "superb" quality... but still the reviews of the product and the video do claim so.

    Originally Posted by pandy View Post
    Well... active VGA splitter will provide proper signal conditioning - passive splitters will not separate you from typical problems - too low impedance - too many receivers connected to 75ohm output - this may reduce signal level, reduce bandwidth, introduce some phase distortions in analog signal and in very bad case scenario it may damage damage signal source (usually not the case but theoretically possible in badly designed HW).

    In your connection diagram - double load may be present ot CVBS line - this ma reduce level of signal - important for synchronization pulses - some devices can be more tolerant some not, additionally to insufficient level, SNR margin may be too low from SYNC stripper perspective (will lead to increased jitter and other problems).
    I have a VGA spliter, but it's passive. I think keeping analog signals in optimal conditions is too expensive for my hobbie purposes. However, I admit that I should have bought a better quality cable for the console. I do regret that.

    What region are you in?
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  13. Originally Posted by magiblot View Post
    I have a VGA spliter, but it's passive. I think keeping analog signals in optimal conditions is too expensive for my hobbie purposes. However, I admit that I should have bought a better quality cable for the console. I do regret that.

    What region are you in?
    Central Europe - Poland
    At least you could try to search for VGA amplifier/splitter like this https://www.amazon.com/Monoprice-2-Way-Splitter-Amplifier-Multiplier/dp/B001UW7YDS - should work perfectly. I mentioned VGA to BNC cables as they can be found in local PC parts shops for bargain price - currently almost no one use analog VGA.
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  14. Member Skiller's Avatar
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    Originally Posted by magiblot View Post
    In addition, they did a very ugly thing some years ago:

    https://www.retrogamingcables.co.uk/nintendo/nes/nintendo-nes-av-composite-audio-video...e-tv-lead-cord

    https://www.youtube.com/watch?v=-xCsU_Ss9FY

    That product is obviously not going to provide "superb" quality... but still the reviews of the product and the video do claim so.
    The NES, unless modified (which requires some very hard to get parts), doesn't output anything other than Composite video. Hence that's the best you can get from it, the cable is fine (?!).


    What console are we talking about in your case?
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    Originally Posted by pandy View Post
    Central Europe - Poland
    At least you could try to search for VGA amplifier/splitter like this https://www.amazon.com/Monoprice-2-Way-Splitter-Amplifier-Multiplier/dp/B001UW7YDS - should work perfectly. I mentioned VGA to BNC cables as they can be found in local PC parts shops for bargain price - currently almost no one use analog VGA.
    Unfortunately, it seems to me that the quality of these products is too high for what I'm doing. I'll take it into consideration if I ever do something serious, but I think this is not the time.

    I asked for your region because I feel like BNC cables for video are rarely used out of the professional sphere where I live (Spain). I don't know if I would be able to find these cheap here.

    Originally Posted by Skiller View Post
    Originally Posted by magiblot View Post
    In addition, they did a very ugly thing some years ago:

    https://www.retrogamingcables.co.uk/nintendo/nes/nintendo-nes-av-composite-audio-video...e-tv-lead-cord

    https://www.youtube.com/watch?v=-xCsU_Ss9FY

    That product is obviously not going to provide "superb" quality... but still the reviews of the product and the video do claim so.
    The NES, unless modified (which requires some very hard to get parts), doesn't output anything other than Composite video. Hence that's the best you can get from it, the cable is fine (?!).


    What console are we talking about in your case?
    Composite video will always look bad. Hence, I don't understand why the reviews of the product are so positive, and why they posted a video with an actual emulator capture of the game. That's what I claim.

    In my case, the console is a PAL GameCube:

    http://gamesx.com/wiki/doku.php?id=av:nintendomultiav
    http://members.optusnet.com.au/eviltim/gamescart/gamescart.htm#gamecube
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  16. Originally Posted by magiblot View Post

    Unfortunately, it seems to me that the quality of these products is too high for what I'm doing. I'll take it into consideration if I ever do something serious, but I think this is not the time.

    I asked for your region because I feel like BNC cables for video are rarely used out of the professional sphere where I live (Spain). I don't know if I would be able to find these cheap here.
    Well, seem you facing particular problems and you searching problem solution - that's why i proposed such approach.
    Prices are always to high but ... https://www.amazon.es/s/ref=sr_st?keywords=vga+bnc+cable&rh=i%3Aaps%2Ck%3Avga+bnc+cabl...price-asc-rank or https://www.ebay.es/sch/i.html?_from=R40&_sacat=0&_nkw=vga+bnc+cable&_sop=15

    https://www.amazon.es/Duplicador-UGREEN-Adaptador-monitores-1920X1440/dp/B01F37AVWQ/re...Duplicador+VGA

    FYI companies frequently throwing such cables - go to nearest computer junkyard and probably for a few euros you will be able to create whole required set.
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  17. Member Skiller's Avatar
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    Originally Posted by magiblot View Post
    In my case, the console is a PAL GameCube
    Alright, you have seen this cable right?

    https://www.retrogamingcables.co.uk/nintendo/gamecube/NINTENDO-GAMECUBE-RGB-SCART-CABL...ITE-SYNC-CSYNC

    It would fix the interference by curing the cause of it. And except maybe the price, I don't see anything wrong with that cable.

    Probably even the one wired for standard Composite video for sync would help because it's screened.
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    Originally Posted by Skiller View Post
    Originally Posted by magiblot View Post
    In my case, the console is a PAL GameCube
    Alright, you have seen this cable right?

    https://www.retrogamingcables.co.uk/nintendo/gamecube/NINTENDO-GAMECUBE-RGB-SCART-CABL...ITE-SYNC-CSYNC

    It would fix the interference by curing the cause of it. And except maybe the price, I don't see anything wrong with that cable.

    Probably even the one wired for standard Composite video for sync would help because it's screened.
    If I'm ever to upgrade my cable, I'll probably buy one from that page, despite what I said before about their NES cable.

    However, it's possible that my DVD recorder doesn't accept just composite sync instead of full composite video. I suspect this because the device wouldn't accept the video signal from the computer I use for playing on a CRT with a RGB to SCART adapter and the proper hardware configuration. I have to admit that I could only try with a progressive video mode (288p 50Hz, tolerated by the TV), so that might also be the reason. But I think the composite sync is farther from the standards than low-res progressive video.
    Last edited by magiblot; 30th Jun 2017 at 12:46.
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