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Hi all,

Out of curiosity (and in case anyone has some kind of magic trick): why does the image flickers on my 2 older flatscreens (around 2010) but no issues on my 2021 QLed TV???

My set up is : generic AV cable (white + yellow) -> RCA splitter -> RCA to HDMi upscaler (with 1080p 720p switch)

I know nothing is faulty as each item works well seperately and the setup works fine on my 2021 flatscreen.

On my old flatscreen where I play retro, I have 0 issues with my other retro consoles except my SMS 1. Weird?!?!

Willing to give details, pictures, video if anyone needs more info :)

Thanks!

It's possible the older TV just doesn't like the signal being fed to it. Especially if the upscaler isn't handling the (technically out of spec) signal being fed into it correctly.

Also, for what it's worth. Products such as the RetroTink line will probably get a much better result (in terms of input lag, quality, and compatibility) than generic Composite to HDMI converters.

Flygon wrote

(technically out of spec)

In what sense do you mean out of spec? Are these RCA to HDMI converters not simply designed to take some defined analogue signal (e.g. PAL / NTSC) and retransmit it as an HDMI-compliant digital signal?

@Kimoya I am curious to know what kind of flickering you mean, so a video might be interesting if you have time. If it's quite occasional (e.g. every 10 - 60 seconds) momentary dropouts it might imply that the screens are losing timing sync on the signal. I've seen this before on my own travels with HDMI in particular when there's too much jitter on the signal and / or the conductor lengths are mismatched; and definitely I've got some screens which are really tolerant of signal quality and one in particular which is extremely fussy.

On the other hand, if it's high frequency flicker of the order of framerate, I think that would imply some timing discrepancy at a lower level. I implemented a crude doubling upscaler by interlacing the lines and this resulted in noticeable flicker on LCD screens, because they don't have the same persistence of luminescence profile that old CRT screens had - you can easily perceived interlacing at 30Mhz. Your upscaler may be taking a similar shortcut to line upscaling! The alternative is to use line buffers which is certainly more expensive in hardware to implement.

It's feeling like the quality of the upscaler is the most likely factor here, although you could also play around with different cables and cable lengths too, especially on the HDMI side.

Thanks for your input!

Yes its a cheap generic upscaler. I bought it to bypass a color cycling issue I had using the componant input (again, only with SMS, other consoles worked fine!!).

The problem is intermittent and varies in intensity depending on the game. You ll see average flickers with Wonder Boy in the video below, but My Hero has much worse flickering?!

Yeah okay I see what you mean!

Very quick gut feel looking at that is that the upscaler to HDMI link is not the problem; rather I think the upscaler is having trouble maintaining video sync on the analogue side, so I'd immediately be wondering about the analogue cabling.

Have you tried it with just the video component, i.e. no audio?

Just tried and no change.

As said, it works flawlessly on my 2021 Qled Samsung TV.

Flickers are on a 20(09-10-11) Panasonic, and even on an older flatscreen. On that older flatscreen which has RCA input, it works fine straight with the RCA cable so I know the cable is fine.

I do have another old samsung flatscreen, I should give it a try.

Cool, so sounds like you've proven the splitter is okay, and by plugging the composite video directly into one of the flickery TVs, you've proven that the hardware in that TV is at least capable of making the A to D conversion well enough to render the video directly (although it likely won't be going via HDMI to do so); seems like the only logical conclusion is that the upscaler is the problem.

Whether it's outputting bad HDMI or whether the HDMI is within tolerance and it's the video sync that's the problem, either way I suspect that your newer TV is simply more tolerant of the minor imperfections than the older ones.

Might be time to trial some new upscalers!

EDIT: out of interest, does it do any better if you switch the upscaler to 720p? If the problem is on the HDMI side, I would have expected switching to 720p to make things somewhat or even much better. If no difference, likely the upscaler is struggling with the video sync.

Flygon wrote

Products such as the RetroTink line will probably get a much better result (in terms of input lag, quality, and compatibility) than generic Composite to HDMI converters.

Also, thanks for link to RetroTink, @Flygon, that looks like a really fantastic product line - I'm constantly discovering all this great work people are doing through this forum, it's really inspiring.
(for those who care about such details, from inspecting the photos looks like RetroTink uses an Analog HDMI transmitter chip, which is a solid choice when price point isn't a huge issue. Would be interested to know how they are achieving the line doubling – or 5x-ing for that matter – in hardware...)

Yes I tried the switch 720p and 1080p, it does modify the intensity of flickers depending on games, but it does not solve the issue.

willbritton wrote

Flygon wrote

(technically out of spec)

In what sense do you mean out of spec? Are these RCA to HDMI converters not simply designed to take some defined analogue signal (e.g. PAL / NTSC) and retransmit it as an HDMI-compliant digital signal?

The one thing I know is out-of-spec about most retro consoles is being designed for 240p (or whatever its PAL equivalent is) rather than the official 480i spec.
CRTs could be tricked to playing along.
I saw that issue as far back as my PS2. My generic component cable would display PS2 games just fine, but pop in a PS1 game and the video becomes glitched.

That's not really being out of spec though. A console with NTSC output by definition can only produce a composite analogue signal encoding 525 interlaced scanlines per frame which is 262.5 lines per field. Similarly, a console with PAL output by definition can only produce a composite analogue signal encoding (in most geographies) 625 interlaced scanlines per frame which is 312.5 lines per field.

When you say "240p" that really doesn't have a great deal of meaning in the world of the main composite analogue standards of the time. The SMS created a 192 line high display (for most games - it could go up to 240) simply by driving the analogue standard with the interlaced lines from the display (96 per field for 192 high displays) and attaching some appropriate amount of border to the top and bottom of the picture to account for the remaining 70 or 71 lines (for NTSC) per field.

None of that is "out of spec" - from the TV's point of view it's no different at all from receiving a broadcast over the RF interface, demodulating it and displaying it.

When it comes to HDMI, there are a finite number of standard video formats that HDMI displays (technically known as "sinks") can possibly support, and some very strict rules about how they should be encoded. Apart from 640x480@60Hz, which all displays are required to support according to the HDMI specs, figuring out which video formats are supported by an HDMI sink is the responsibility of the source (the thing producing the picture, e.g. console) and there is a spec detailing exactly how that negotiation happens.

So the RCA to HDMI upscaler has three jobs:
1. Decode an analogue standard (e.g. NTSC, PAL, SECAM)
2. Scale the image up so that it fits into one of the HDMI standard video formats (in this example only two standards are relevant - 720p and 1080p at 60Hz)
3. Encode the scaled signal to the chosen HDMI format.

None of any of that in concept could be considered "out of spec", in that you can read the specs and find all of it to be correct! However the hardware implementation in the upscaler can of course be suspect. It's worth noting that it's not particularly trivial to do this conversion, especially from PAL analogue which is 50Hz as opposed to 720p and 1080p's 60Hz, so I'm not hugely surprised that e.g. the $10 converters that one can find out there might not be completely up to the job!

KingMike wrote

My generic component cable would display PS2 games just fine, but pop in a PS1 game and the video becomes glitched.

This kind of intrigued me, and interestingly I came across this footnote on Wikipedia:

Quote

Contrary to popular belief, the PS2's YPBPR/component output fully supports 240p and games from the original PlayStation. However, 240p output isn't part of the YPBPR standard, thus not all HDTVs support it. Upscaling can be used as a workaround.

I checked my own PS2 and in the System Configuration settings you can switch between RGB and YPbPr output. You might find that simply switching to RGB output will solve your PS1 game problems. That said, my PS2 can play PS1 games fine on either mode, but I suppose that's down to my TV...
(note that this 240p out-of-specness is specifically to do with the YPbPr component interface and not to do with analogue in general or with the composite video found on the SMS)

What KingMike means by 240p being “out of spec” is that these consoles modify the timing of odd fields to be early so that the both the odd and even fields occur on the same lines instead of being interleaved. The result is 240p instead of 480i.

I don’t think that will change going to component output, but it’s all about trying which combinations of TV, TV settings, converter, cable, etc work and which don’t. Good luck.

UPDATE INFO

I realized there was one cable I did not test: the RCA that came with my brand new RCA splitter, plugged between the RCA switcher and the upscaler.

Turns out small things like this can make a huge difference depending on wich TV you try.... 1rst other RCA cable I tried, awful...flclickering 95% of the time. 2nd one I tested : almost perfect! A few flickers here and there but nothing compared to the video I posted!

I didnt test on my other TVs but Im curious about the results

Ah that is interesting! As I said, had a hunch looking at your YouTube video that something might be degraded on the analogue side. My best theory is still that the analogue signal is degraded to a sufficient extent that the upscaler occasionally misses some sync info and the older TVs don't "fill in the blanks" in the same way that your newer TVs do.

But I think I misunderstood before - you actually have an RCA _switch_ between your SMS and the upscaler? I thought you were just talking about a simple splitter cable to pass the mono audio audio to dual left/right RCA.

Did you try it without the switch - i.e. direct from the SMS to the upscaler?

Anyway, glad it's working better now!

Yes I have a 3-in /1-out RCA switcher so I can play 3 retro consoles through 1 hdmi upscaler.

I dont remember if I tried straight from SMS to the upscaler, might as well try. But yeah very happy as the whole goal was to be able to play those consoles on that particular TV :)

Author	Message
Kimoya Joined: 23 Jul 2022 Posts: 9	Flickering on some flatscreens via hdmi upscaler Posted: Mon Aug 15, 2022 2:16 am
Kimoya Joined: 23 Jul 2022 Posts: 9	Hi all, Out of curiosity (and in case anyone has some kind of magic trick): why does the image flickers on my 2 older flatscreens (around 2010) but no issues on my 2021 QLed TV??? My set up is : generic AV cable (white + yellow) -> RCA splitter -> RCA to HDMi upscaler (with 1080p 720p switch) I know nothing is faulty as each item works well seperately and the setup works fine on my 2021 flatscreen. On my old flatscreen where I play retro, I have 0 issues with my other retro consoles except my SMS 1. Weird?!?! Willing to give details, pictures, video if anyone needs more info :) Thanks!

Flygon Joined: 30 Jun 2016 Posts: 196 Location: Melbourne, Australia	Posted: Mon Aug 15, 2022 7:16 am
	It's possible the older TV just doesn't like the signal being fed to it. Especially if the upscaler isn't handling the (technically out of spec) signal being fed into it correctly. Also, for what it's worth. Products such as the RetroTink line will probably get a much better result (in terms of input lag, quality, and compatibility) than generic Composite to HDMI converters.

willbritton Joined: 06 Mar 2022 Posts: 670 Location: London, UK	Posted: Mon Aug 15, 2022 8:21 am
	Flygon wrote (technically out of spec) In what sense do you mean out of spec? Are these RCA to HDMI converters not simply designed to take some defined analogue signal (e.g. PAL / NTSC) and retransmit it as an HDMI-compliant digital signal? @Kimoya I am curious to know what kind of flickering you mean, so a video might be interesting if you have time. If it's quite occasional (e.g. every 10 - 60 seconds) momentary dropouts it might imply that the screens are losing timing sync on the signal. I've seen this before on my own travels with HDMI in particular when there's too much jitter on the signal and / or the conductor lengths are mismatched; and definitely I've got some screens which are really tolerant of signal quality and one in particular which is extremely fussy. On the other hand, if it's high frequency flicker of the order of framerate, I think that would imply some timing discrepancy at a lower level. I implemented a crude doubling upscaler by interlacing the lines and this resulted in noticeable flicker on LCD screens, because they don't have the same persistence of luminescence profile that old CRT screens had - you can easily perceived interlacing at 30Mhz. Your upscaler may be taking a similar shortcut to line upscaling! The alternative is to use line buffers which is certainly more expensive in hardware to implement. It's feeling like the quality of the upscaler is the most likely factor here, although you could also play around with different cables and cable lengths too, especially on the HDMI side.

Kimoya Joined: 23 Jul 2022 Posts: 9	Posted: Mon Aug 15, 2022 2:17 pm
Kimoya Joined: 23 Jul 2022 Posts: 9	Thanks for your input! Yes its a cheap generic upscaler. I bought it to bypass a color cycling issue I had using the componant input (again, only with SMS, other consoles worked fine!!). The problem is intermittent and varies in intensity depending on the game. You ll see average flickers with Wonder Boy in the video below, but My Hero has much worse flickering?!

willbritton Joined: 06 Mar 2022 Posts: 670 Location: London, UK	Posted: Mon Aug 15, 2022 2:28 pm
	Yeah okay I see what you mean! Very quick gut feel looking at that is that the upscaler to HDMI link is not the problem; rather I think the upscaler is having trouble maintaining video sync on the analogue side, so I'd immediately be wondering about the analogue cabling. Have you tried it with just the video component, i.e. no audio?

Kimoya Joined: 23 Jul 2022 Posts: 9	Posted: Mon Aug 15, 2022 2:37 pm
Kimoya Joined: 23 Jul 2022 Posts: 9	Just tried and no change. As said, it works flawlessly on my 2021 Qled Samsung TV. Flickers are on a 20(09-10-11) Panasonic, and even on an older flatscreen. On that older flatscreen which has RCA input, it works fine straight with the RCA cable so I know the cable is fine. I do have another old samsung flatscreen, I should give it a try.

willbritton Joined: 06 Mar 2022 Posts: 670 Location: London, UK	Posted: Mon Aug 15, 2022 4:10 pm
	Cool, so sounds like you've proven the splitter is okay, and by plugging the composite video directly into one of the flickery TVs, you've proven that the hardware in that TV is at least capable of making the A to D conversion well enough to render the video directly (although it likely won't be going via HDMI to do so); seems like the only logical conclusion is that the upscaler is the problem. Whether it's outputting bad HDMI or whether the HDMI is within tolerance and it's the video sync that's the problem, either way I suspect that your newer TV is simply more tolerant of the minor imperfections than the older ones. Might be time to trial some new upscalers! EDIT: out of interest, does it do any better if you switch the upscaler to 720p? If the problem is on the HDMI side, I would have expected switching to 720p to make things somewhat or even much better. If no difference, likely the upscaler is struggling with the video sync.

willbritton Joined: 06 Mar 2022 Posts: 670 Location: London, UK	Posted: Mon Aug 15, 2022 4:24 pm
	Flygon wrote Products such as the RetroTink line will probably get a much better result (in terms of input lag, quality, and compatibility) than generic Composite to HDMI converters. Also, thanks for link to RetroTink, @Flygon, that looks like a really fantastic product line - I'm constantly discovering all this great work people are doing through this forum, it's really inspiring. (for those who care about such details, from inspecting the photos looks like RetroTink uses an Analog HDMI transmitter chip, which is a solid choice when price point isn't a huge issue. Would be interested to know how they are achieving the line doubling – or 5x-ing for that matter – in hardware...)

Kimoya Joined: 23 Jul 2022 Posts: 9	Posted: Mon Aug 15, 2022 5:57 pm
Kimoya Joined: 23 Jul 2022 Posts: 9	Yes I tried the switch 720p and 1080p, it does modify the intensity of flickers depending on games, but it does not solve the issue.

KingMike Joined: 14 Oct 2008 Posts: 510	Posted: Mon Aug 15, 2022 6:32 pm
KingMike Joined: 14 Oct 2008 Posts: 510	willbritton wrote Flygon wrote (technically out of spec) In what sense do you mean out of spec? Are these RCA to HDMI converters not simply designed to take some defined analogue signal (e.g. PAL / NTSC) and retransmit it as an HDMI-compliant digital signal? The one thing I know is out-of-spec about most retro consoles is being designed for 240p (or whatever its PAL equivalent is) rather than the official 480i spec. CRTs could be tricked to playing along. I saw that issue as far back as my PS2. My generic component cable would display PS2 games just fine, but pop in a PS1 game and the video becomes glitched.

willbritton Joined: 06 Mar 2022 Posts: 670 Location: London, UK	Posted: Mon Aug 15, 2022 8:40 pm Last edited by willbritton on Tue Aug 16, 2022 9:34 am; edited 2 times in total
	That's not really being out of spec though. A console with NTSC output by definition can only produce a composite analogue signal encoding 525 interlaced scanlines per frame which is 262.5 lines per field. Similarly, a console with PAL output by definition can only produce a composite analogue signal encoding (in most geographies) 625 interlaced scanlines per frame which is 312.5 lines per field. When you say "240p" that really doesn't have a great deal of meaning in the world of the main composite analogue standards of the time. The SMS created a 192 line high display (for most games - it could go up to 240) simply by driving the analogue standard with the interlaced lines from the display (96 per field for 192 high displays) and attaching some appropriate amount of border to the top and bottom of the picture to account for the remaining 70 or 71 lines (for NTSC) per field. None of that is "out of spec" - from the TV's point of view it's no different at all from receiving a broadcast over the RF interface, demodulating it and displaying it. When it comes to HDMI, there are a finite number of standard video formats that HDMI displays (technically known as "sinks") can possibly support, and some very strict rules about how they should be encoded. Apart from 640x480@60Hz, which all displays are required to support according to the HDMI specs, figuring out which video formats are supported by an HDMI sink is the responsibility of the source (the thing producing the picture, e.g. console) and there is a spec detailing exactly how that negotiation happens. So the RCA to HDMI upscaler has three jobs: 1. Decode an analogue standard (e.g. NTSC, PAL, SECAM) 2. Scale the image up so that it fits into one of the HDMI standard video formats (in this example only two standards are relevant - 720p and 1080p at 60Hz) 3. Encode the scaled signal to the chosen HDMI format. None of any of that in concept could be considered "out of spec", in that you can read the specs and find all of it to be correct! However the hardware implementation in the upscaler can of course be suspect. It's worth noting that it's not particularly trivial to do this conversion, especially from PAL analogue which is 50Hz as opposed to 720p and 1080p's 60Hz, so I'm not hugely surprised that e.g. the $10 converters that one can find out there might not be completely up to the job!

willbritton Joined: 06 Mar 2022 Posts: 670 Location: London, UK	Posted: Mon Aug 15, 2022 11:14 pm
	KingMike wrote My generic component cable would display PS2 games just fine, but pop in a PS1 game and the video becomes glitched. This kind of intrigued me, and interestingly I came across this footnote on Wikipedia: Quote Contrary to popular belief, the PS2's YPBPR/component output fully supports 240p and games from the original PlayStation. However, 240p output isn't part of the YPBPR standard, thus not all HDTVs support it. Upscaling can be used as a workaround. I checked my own PS2 and in the System Configuration settings you can switch between RGB and YPbPr output. You might find that simply switching to RGB output will solve your PS1 game problems. That said, my PS2 can play PS1 games fine on either mode, but I suppose that's down to my TV... (note that this 240p out-of-specness is specifically to do with the YPbPr component interface and not to do with analogue in general or with the composite video found on the SMS)

asynchronous Joined: 14 Aug 2000 Posts: 742 Location: Adelaide, Australia	Flickering on some flatscreens via hdmi upscaler Posted: Tue Aug 16, 2022 1:17 am
	What KingMike means by 240p being “out of spec” is that these consoles modify the timing of odd fields to be early so that the both the odd and even fields occur on the same lines instead of being interleaved. The result is 240p instead of 480i. I don’t think that will change going to component output, but it’s all about trying which combinations of TV, TV settings, converter, cable, etc work and which don’t. Good luck.

Kimoya Joined: 23 Jul 2022 Posts: 9	Posted: Wed Aug 17, 2022 10:20 pm
Kimoya Joined: 23 Jul 2022 Posts: 9	UPDATE INFO I realized there was one cable I did not test: the RCA that came with my brand new RCA splitter, plugged between the RCA switcher and the upscaler. Turns out small things like this can make a huge difference depending on wich TV you try.... 1rst other RCA cable I tried, awful...flclickering 95% of the time. 2nd one I tested : almost perfect! A few flickers here and there but nothing compared to the video I posted! I didnt test on my other TVs but Im curious about the results

willbritton Joined: 06 Mar 2022 Posts: 670 Location: London, UK	Posted: Thu Aug 18, 2022 9:27 am
	Ah that is interesting! As I said, had a hunch looking at your YouTube video that something might be degraded on the analogue side. My best theory is still that the analogue signal is degraded to a sufficient extent that the upscaler occasionally misses some sync info and the older TVs don't "fill in the blanks" in the same way that your newer TVs do. But I think I misunderstood before - you actually have an RCA _switch_ between your SMS and the upscaler? I thought you were just talking about a simple splitter cable to pass the mono audio audio to dual left/right RCA. Did you try it without the switch - i.e. direct from the SMS to the upscaler? Anyway, glad it's working better now!

Kimoya Joined: 23 Jul 2022 Posts: 9	Posted: Thu Aug 18, 2022 6:10 pm
Kimoya Joined: 23 Jul 2022 Posts: 9	Yes I have a 3-in /1-out RCA switcher so I can play 3 retro consoles through 1 hdmi upscaler. I dont remember if I tried straight from SMS to the upscaler, might as well try. But yeah very happy as the whole goal was to be able to play those consoles on that particular TV :)

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