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Vertical lines in 480i with Conexant video encoder


8769F
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Hi everyone,

There are numerous posts throughout the interwebs with people reporting vertical lines showing in the boot animation and MS dashboard when running in 480i.  The standard response when people bring up the issue seems to be be 'check your capacitors' and 'just force 480p'.  I've seen some people report their caps are either fine, or they replaced them with no change, and I know that forcing 480p does fix the issue, but what I would like to understand is, are there systems using the Conexant encoder which don't suffer from this 480i issue, or is there anyone who had the issue who actually solved the issue by replacing caps and if so, which capacitors solved the issue?

Thanks for any feedback.  This just seems like one of those issues which have affected a number of people but that the community maybe doesn't understand the actual cause.

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3 hours ago, 8769F said:

Hi everyone,

There are numerous posts throughout the interwebs with people reporting vertical lines showing in the boot animation and MS dashboard when running in 480i.  The standard response when people bring up the issue seems to be be 'check your capacitors' and 'just force 480p'.  I've seen some people report their caps are either fine, or they replaced them with no change, and I know that forcing 480p does fix the issue, but what I would like to understand is, are there systems using the Conexant encoder which don't suffer from this 480i issue, or is there anyone who had the issue who actually solved the issue by replacing caps and if so, which capacitors solved the issue?

Thanks for any feedback.  This just seems like one of those issues which have affected a number of people but that the community maybe doesn't understand the actual cause.

My pal console does the same with component cable when using interlaced PAL signal, it's universal thing for consoles with conexant chip. Everything fixes when using 480p mode. I don't have means to test with composite, i may test with original scart cable, but not sure where i put it. :\

Focus and xcalibur chips dont have this problem.

Original xbox really had crappy video output compared to less complex, but reliable ps2 video output. Microsoft really failed at this.

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7 minutes ago, prtscn said:

My pal console does the same with component cable when using interlaced PAL signal, it's universal thing for consoles with conexant chip. Everything fixes when using 480p mode. I don't have means to test with composite, i may test with original scart cable, but not sure where i put it. 😕

Focus and xcalibur chips dont have this problem.

Original xbox really had crappy video output compared to less complex, but reliable ps2 video output. Microsoft really failed at this.

Great information thanks.  Composite works fine for me, so it's just the component inputs at 480i.  I was really hoping to establish with some good certainty that consoles with Conexant encoders just have this behavior, and it's not indicative of a failed/failing component.  I think that solidifying this can help people with the problem in the future so they understand it's expected behavior, and that while they can recap to their hearts content it's not going to change the bars.

Happy to hear from any others as well for more confirmation.  And if anyone has a Conexant console that doesn't show the problem that would be particularly interesting to discover.

I'm actually looking at signals from a Conexant and a Focus encoder on a scope right now just to see if I can 'spot' the bars in the waveforms.

Thanks!

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1 minute ago, 8769F said:

Great information thanks.  Composite works fine for me, so it's just the component inputs at 480i.  I was really hoping to establish with some good certainty that consoles with Conexant encoders just have this behavior, and it's not indicative of a failed/failing component.  I think that solidifying this can help people with the problem in the future so they understand it's expected behavior, and that while they can recap to their hearts content it's not going to change the bars.

Happy to hear from any others as well for more confirmation.  And if anyone has a Conexant console that doesn't show the problem that would be particularly interesting to discover.

I'm actually looking at signals from a Conexant and a Focus encoder on a scope right now just to see if I can 'spot' the bars in the waveforms.

Thanks!

check if it outputs have correct clocks, etc.

funny how less advanced console had better pal/ntsc output. Less is more. And if you read more, xbox is a nightmare story, how it process ntsc/pal signals, simply makes from bad to worse.

https://www.avforums.com/threads/xbox-flicker-filter-and-why-the-picture-is-soft-from-rgb-scart.196390/

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22 hours ago, prtscn said:

check if it outputs have correct clocks, etc.

funny how less advanced console had better pal/ntsc output. Less is more. And if you read more, xbox is a nightmare story, how it process ntsc/pal signals, simply makes from bad to worse.

https://www.avforums.com/threads/xbox-flicker-filter-and-why-the-picture-is-soft-from-rgb-scart.196390/

Still looking at the Y luma/sync waveforms and (through lack of experience I'm sure) nothing is jumping out at me.  My read on the article above doesn't mention vertical bars only softness, but do you think the flicker filter is to blame?

Going to stare at these waves a bit more.  Attached is a sample, with the top being the good clean signal from a 1.6 system, and the other the dirty Connexant.  Obviously these are a wide shot so the detail isn't there for analysis, but I'm zooming into different parts and looking to see if I can point to something.

 

OGXBox-CH1_16Clean-CH4_13Bars.png

Edited by 8769F
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5 hours ago, 8769F said:

Still looking at the Y luma/sync waveforms and (through lack of experience I'm sure) nothing is jumping out at me.  My read on the article above doesn't mention vertical bars only softness, but do you think the flicker filter is to blame?

Going to stare at these waves a bit more.  Attached is a sample, with the top being the good clean signal from a 1.6 system, and the other the dirty Connexant.  Obviously these are a wide shot so the detail isn't there for analysis, but I'm zooming into different parts and looking to see if I can point to something.

 

OGXBox-CH1_16Clean-CH4_13Bars.png

You may connect all 3 wires at the same time, maybe other colors do something. I may test 50i with only 1 wire on TV, to see if anything changes from jailbar perspective.

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Progress this morning.  I was really struggling because all of the stock dashboard screens where I could see the 480i jailbars had movement in them because of background animation stuff so it was really hard to compare two signals.  Then it hit me that I had some modded systems running XMBC4Gamers that I could force into 480i, and then load up an NTSC color test pattern.  Once I did that I was able to start to see some differences in the signal that likely corresponds to the jailbars.  See some attached pictures for examples.  Channel 1 is a version 1.6 which has no jailbars, and Channel 4 is a 1.2 with Connexant that shows the issue.

While this doesn't solve any issues it at least gives a quantitative look at what many in the community have seen.  At this point unless someone comes forth with a Conexant system which doesn't show jailbars in 480i, I think the conclusion should be that this is behavior of the Conexant chipset and it's not a symptom of bad caps.

480iJailbars-CH1v16-CH4v12-001.png

480iJailbars-CH1v16-CH4v12-002.png

480iJailbars-CH1v16-CH4v12-003.png

480iJailbars-CH1v16-CH4v12-004.png

Edited by 8769F
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