Onkyo video processor is the cause of video colour banding

geogan

Well-known Member
So I have been seeing horrible colour banding in various movies and TV programmes since I upgraded my projector to Sony VPL-40ES.

It usually was apparent in scenes which have low lighting and gradient type images such as Game of Thrones or moody dark movies.

Affect is similar to this (but moving and strobing as the patterns change with light changes):

colour-banding.png


Any way for a long time I blamed Sony's SXRD technology for the problem because I couldn't see any other reason for it - after all I had set the video mode on the Onkyo TX-SR608 reciever to "Through" mode and didn't have it set to process the image in any way.
With "Through" mode you would expect a bit-for-bit copy of HDMI In -> HDMI Out

But it appears this is not the case with this reciever (and maybe others - more on that later)

So I was astounded to discover that if I removed the Onkyo reciever completely from the HDMI chain and just went source direct to projector (or even, as I have, source to Sony headphone amp to HDMI splitter box to projector) then the banding was gone - back to normal compression artifacts associated with source material only (which may be slightly bandy because of severe compression).

So then I had to figure out how/why the reciever was doing this - there was nothing in manual and nothing in menus to turn off.

Then I searched online and saw a post talking about the "Through" mode not completely removing processing and there was a secret operation to remove video processing completely.

This is it:

Onkyo TX-SR608 - Important find | AVForums

"If you really want to turn off all video processing:
Press VCR/DVR and RETURN on the AV receiver at the same time.
Select "Skip" in the "VideoProcessor" setting by pressing RETURN repeatedly on the display.
To reset back to the original setting, press the same button at the same time. "

P1140141(1).JPG

P1140142(1).JPG


When I do this and set to SKIP, the banding goes completely (you can tell the operation is major change because it causes the display to go blank as the source/display re-do HDMI handshaking)

The downside is you no longer have the on-screen Onkyo menus/volume overlays


I don't know how many other Onkyo models this affects, but any Onkyo owners could try to do similar procedure and see what happens.
Don't know if this is something to do with the Faroudja chip (does this do the overlays?)


Here's what it looks like in a scene from last weeks "Game of Thrones" on Sky Atlantic HD (33 minutes in where Sanza goes to visit Reek in the dog kennels if you want to check this scene on your own reciever)

This was a difficult image to capture - required a Panasonic GH4 camera in full manual mode mounted on large tripod to capture as the scene is very dark.

I have slighly overexposed the image so you can see the banding - it is very clear when I view projected image with my own F1.0 eyes but F3.5 lens is not so good!
Both images were taken with same settings of 1.6 seconds exposure at F4.1 and minimum camera ISO of 200 (no idea why GH4 can't do ISO 100)

VPROCESSOR:USE

P1140123(1).JPG


Zoomed to top-left:
P1140123-crop.JPG


Here's what it looks like with processing skipped through hidden menu in reciever.
Note it still looks a tiny bit banding but that's just the camera capture - on screen it looks more or less a smooth gradient.

VPROCESSOR:SKIP

P1140124(1).JPG


Zoomed to top-left:
P1140124-crop.JPG


I have seen similar results using a Windows desktop uncompressed 24-bit gradient background - with processing on you get horrible gradients and colour patterns, with it off you get a natural smooth gradient.

I may post these too as it is even more obvious with these examples...



Doing this also apparently fixes other things I noticed like stutter in certain display modes in certain movies. See below post:

Onkyo TX-SR608 - Video "stutter"? - Blu-ray Forum

"You guys need to call onkyo and complain. I called today and and told them of all the problems and they said "we don't listen to forum people, they need to call us about problems". They said they haven't heard of any of the issues yet. I had them test stuff on theirs while I was on the phone and sure enough the guy said he noticed the stutters every 10 seconds or so! They also acknowledged that they did see that the passthrough wasn't sending the signal untouched like it should but it was due to their new chip they used and there isn't a way to fix it. I'm trying to get my money back on mine as these are defects that as for now Onkyo is saying can't be fixed with a firmware update. One of the main reasons I got this unit is the new overlaid OSD and having to go into a secret menu and disable it is not my idea of a fix for picture and performance issues.

I have had the same problem with my 707, though it was easy to get around it. It only happened with 24p in my case, you have to set the video processor to skip on my particular unit (though before a certain firmware it reset each time after a power cycle).

Here a quote from the manual of the 707:
Video equipment can be connected to the AV receiver by using any one of the following video connection formats:
composite video, S-Video, component video, or HDMI, the latter offering the best picture quality.
For optimal video performance, THX recommends that video signals pass through the system without upconver-
sion (e.g., component video input through to component video output).
It is also recommended that you press the [VCR/DVR] and [RETURN] buttons on the AV receiver at the same
time. Select “Skip” in the “VideoProcessor” setting on the display. To reset back to the original setting, press the
same button at the same time.


I think this bug is present in every model that features Faroudja DCDi Cinema... at least every Onkyo model. My new 1007 suffers from this as well. It is very noticeable on scrolling credits.

Apparently the tools at Faroudja took the 24p too seriously. The problem is that the Faroudja chip is attempting converting a 23.976p signal to a 24p output. So every 40s or so... a frame is dropped. Way to go Faroudja.
"
 
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Cyprio

Active Member
I guess the only way around this and keeping the overlays is to send video direct to the tv, but only if you're fortunate enough to have a 2 x hdmi output bluray player. Though this will not solve the problem if you have more than 'one' source passing through the receiver - not good!

Edit : sorry, no, you still lose the overlays - so not worth it.
 

geogan

Well-known Member
I guess the only way around this and keeping the overlays is to send video direct to the tv, but only if you're fortunate enough to have a 2 x hdmi output bluray player. Though this will not solve the problem if you have more than 'one' source passing through the receiver - not good!

Edit : sorry, no, you still lose the overlays - so not worth it.
Yes it's not the best, but it's better than nothing. The fact that they included a secret bypass for the processing chip in the firmware tells you they they it might cause problems.

As long as the image is the same now as removing the reciever altogether then I'll live with it.

But I don't like that they kept it secret and had me going mad with banding for a long time since getting the SXRD projector which showed it up glaringly!

I can live without the overlays for now.
 

KelvinS1965

Distinguished Member
When I had an Onkyo 818 I remember there were some particular settings to ensure the video processing was bypass and not just using 'through' ('direct' plus something else seems to come to mind?). I use a JVC X500 and a Lumagen 2041 video processor so I wouldn't want a lowly AVR messing with the video, yet I don't recall issues with mine.

Thankfully I sold the 818 (never did like the sound of it) so I'm using a really old school pre HDMI processor until I can get a DTS:X one probably next year. It's surprising how soon you get used to not having overlays on the screen, this is despite all my gear being outside the room. I do have a fairly simple set up, but I know the typical listening levels I watch films at and I've set the maximum volume up to deal with this. I just hold the volume button down a few seconds then watch a film at this pre determined level. Of course if you feel the need to keep checking other settings then I suppose you must have overlay...
 

Iris86

Standard Member
That is unbelievable. Even the processing skipped picture looks bad (I'd reject a master like that fast!) but what the AVR is doing to it is nuts.
 

geogan

Well-known Member
When I had an Onkyo 818 I remember there were some particular settings to ensure the video processing was bypass and not just using 'through' ('direct' plus something else seems to come to mind?). I use a JVC X500 and a Lumagen 2041 video processor so I wouldn't want a lowly AVR messing with the video, yet I don't recall issues with mine.

Thankfully I sold the 818 (never did like the sound of it) so I'm using a really old school pre HDMI processor until I can get a DTS:X one probably next year. It's surprising how soon you get used to not having overlays on the screen, this is despite all my gear being outside the room. I do have a fairly simple set up, but I know the typical listening levels I watch films at and I've set the maximum volume up to deal with this. I just hold the volume button down a few seconds then watch a film at this pre determined level. Of course if you feel the need to keep checking other settings then I suppose you must have overlay...
Yeah the amp is just sitting to the right so I can look over to see the volume etc so that's not a problem. Would be bad alright if it was in another room.

You would think Onkyo would ahve made sure that the video processor they use to generate menus, volume and other screen overlays from amp would NOT be modifying or degrading the actual image in any way when the overlays are not even present on the screen!

The annoying thing though is this SKIP setting is not persistent so every time I turn on the amp I will have to do this hidden override as it starts up in USE mode - think someone said on forum somewhere that later models were persistent with this setting (on later firmware) - so obviously Onkyo is aware of this fudge-up with this video processing chip so made sure the hack fix can be made persistent.

It would put me off buying an Onkyo amp again too soon in near future that's for sure...
 

Mark.Yudkin

Distinguished Member
It would put me off buying an Onkyo amp again too soon in near future that's for sure...
Be fair - why would you expect an all-singing, all-dancing, cost almost nothing A/V receiver to do a better job that the dedicated TV you bought to display the picture?

The THX spec requires pass-through video. This is why THX receivers such as Onkyo's must support pass-through video and why the product's manual must tell you how to achieve THX video.

There are exceptions, but in general, the AV receiver is usually the worst place to process the video. Your results are by no means specific to Onkyo.
 

geogan

Well-known Member
Be fair - why would you expect an all-singing, all-dancing, cost almost nothing A/V receiver to do a better job that the dedicated TV you bought to display the picture?

The THX spec requires pass-through video. This is why THX receivers such as Onkyo's must support pass-through video and why the product's manual must tell you how to achieve THX video.

There are exceptions, but in general, the AV receiver is usually the worst place to process the video. Your results are by no means specific to Onkyo.
What? You appear to have completely misunderstood my whole post.

I don't expect or want the amp to do any video processing.

What I wanted it to do was absolutely nothing to the signal it's passing through. The problem with this amp is the "Through" mode which it allows you to pick does not do this.

It still processes and degrades the passing through HDMI video signal in video "Through" mode.

But it doesn't say this anywhere in manual - the manual makes you believe that pass-through does what you would expect it to do. And it appears so did Onkyo until they discovered the Faroudja chip they used didn't do this.

This is nothing to do with any THX processing.

They put a faulty/buggy overlay display chip in there (possibly the Faroudja one but I can't be sure if that's what does the overlays too).
 
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