HT Slider,

Thanks for the reply. I have a G35 MOBO and the PQ is much much better than I got with a nvidia GPU over the VGA connector into an old panasonic plasma panel. I have recently upgraded the display to HD with HDMI and over HDMI PQ is even better. Having said that I am concidering one or other of the G45 MOBOs you mention get hardware HD decoding. I don't have any of the problems you mentioned in your post.

Ben

This is a very intresting thread...  Am I having similar problems?

Budje:

I also tried the “UseBT601CSC=1” register setting, but this changed nothing.

Or am I missing something here completely?

Are you viewing standard definition (480i/p) or high definition content (720p/1080i/p)?

EDIT:  should have said "standard definition (480i/p/525i/p or anything less than 720p)"

BT.601 (http://en.wikipedia.org/wiki/CCIR_601) defines the standard colorspace used for digital standard definition video (SDTV broadcasts, DVDs, etc.).

BT.709 (http://en.wikipedia.org/wiki/Rec._709) defines the standard colorspace used for digital high definition video (HDTV broadcasts, HD-DVDs, Blu-ray, etc.).

ATI cards treat HD video as using BT.709 so it should produce the correct grey levels for HD by default (assuming you are either using a monitor or using an HDTV with an HDMI connection combined with ATI's HDMI dongle).

Unfortunately ATI cards treat SD video as using sRGB, not BT.601.  sRGB is the "Personal Computer" and Internet standard colorspace and uses an RGB range of 0-255 (not the standard used for video).  Both BT.601 and BT.709 essentially use an RGB range of 16-235 so you can see where this would cause a significant problem for us using our PCs to play back video (TV, DVD, etc.).

EDIT:  Note ATI considers anything with a vertical resolution of less than 720p to be SD.

With ATI cards, if you don't add the UseBT601CSC=1 registry setting, all video with a vertical resolution of less than 720p will processed and treated as sRGB and this produces a strange, washed out image.

The other thing that adds to the confusion is what I have said above only holds true if the ATI video card is using hardware decoding to process the video.  If a software codec is used (like FFDShow), the codec will use its own processing (and typically treat SD video correctly as using BT.601).

Assuming you are having trouble with SD content, likely the reason you didn't see a change with the UseBT601CSC=1 registry entry is because it probably wasn't placed in the correct location.  It is actually quite difficult to figure out where this needs to be added.

One option (probably the best) is to download DXVA Checker from http://bluesky23.hp.infoseek.co.jp/dxvac/DXVAChecker_1900.zip and use it to make the registry change for you.  This is also an excellent tool for diagnosing where hardware decoding is being used vs software and examining what the capabilities of your video card are.  Unfortunately the on-line documentation for DXVA Checker is in Japaneze, but you can "sortof" read it through this link:  http://translate.google.com/translate?sourceid=navclient&hl=en&u=http%3a%2f%2fbluesky23%2ehp%2einfoseek%2eco%2ejp%2findex%2ehtml%23DXVAChecker

If you download and run DXVAChecker (if running Vista, right click on DXVAChecker.exe and run it as Administrator), simply right mouse click anywhere on the main screen and select "Video Acceleration Settings".  In here, scroll down to "UseBT601CSC", turn it on, and set the value to 1.

After that, with XP reboot, or with Vista simply restart Media Center (or whatever you are using to play your video) and you should immediately see a huge difference with SD content.

The way I typically figure out where to add UseBT601CSC=1 without DXVAChecker is to:

1. Start regedit
2. Open up HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Video
3. Scan through the various video devices listed inside this key and find the one with a 0000 and a 0001 where inside the 0000 key contains the key "Catalyst_Version" along with the driver version you are running (for example 08.7).  Note that if you have installed different ATI cards in that system that there may be multiple keys from the older cards.
4. Under that key, open up UMD\DXVA
5. Inside here, create a new string value, rename it "UseBT601CSC" and then change the value to 1.

Another approach is to:

1. Open Catalyst Control Center.
2. Inside Information Center, Graphics Software, copy the 2D driver file path and past it into Notepad.
3. Open regedit and go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class
4. Find the key numbered {????????????} that you pasted earlier into Notepad.
5. Open this key\000\UMD\DXVA and follow step 5 above.

One very common problem is to add the string to the wrong location.  As you can see it is somewhat difficult to find the correct location.  The easiest solution is to simply use DXVAChecker.exe.  I haven't seen it miss yet.

BTW, I tried Ian's registry edits and on my two ATI based systems I couldn't see any changes.  Have any of you found they work with ATI cards?  Which OS version (SP1, TV Pack, etc.) are you running? 

I am running fully updated Vista Home Premium systems, complete with SP1 and all of the patches, but I do not have the TV pack installed.  My video cards are an ATI HD2600XT and an ATI 3870, both with Catalyst 8.7 installed.

Thanks for this quick response :-)

First, it works now! Your trick with DVBchecker reveiled that indeed the setting was still off. Now I could change the "UseBT601CSC" to 1, and as far as I could see now, it is much better now. Now I have an normal lighted image. Black = black. I will offcourse do more checks, but the DVB-C mpeg-2 looks as it is supposed to be.

Are you viewing standard definition (480i/p) or high definition content (720p/1080i/p)?

All. The problem was with the normal PAL signals (so 525i), no NTSC here. With 720p, 1080p the problem went away after changing the LEVEL setting in CoreAVC.

One option (probably the best) is to download DXVA Checker from http://bluesky23.hp.infoseek.co.jp/dxvac/DXVAChecker_1900.zip and use it to make the registry change for you.  This is also an excellent tool for diagnosing where hardware decoding is being used vs software and examining what the capabilities of your video card are.  Unfortunately the on-line documentation for DXVA Checker is in Japaneze, but you can "sortof" read it through this link:  http://translate.google.com/translate?sourceid=navclient&hl=en&u=http%3a%2f%2fbluesky23%2ehp%2einfoseek%2eco%2ejp%2findex%2ehtml%23DXVAChecker

If you download and run DXVAChecker (if running Vista, right click on DXVAChecker.exe and run it as Administrator), simply right mouse click anywhere on the main screen and select "Video Acceleration Settings".  In here, scroll down to "UseBT601CSC", turn it on, and set the value to 1.

After that, with XP reboot, or with Vista simply restart Media Center (or whatever you are using to play your video) and you should immediately see a huge difference with SD content.

This did the trick!

One very common problem is to add the string to the wrong location.  As you can see it is somewhat difficult to find the correct location.  The easiest solution is to simply use DXVAChecker.exe.  I haven't seen it miss yet.

Indeed :-)

BTW, I tried Ian's registry edits and on my two ATI based systems I couldn't see any changes.  Have any of you found they work with ATI cards?  Which OS version (SP1, TV Pack, etc.) are you running? 

I am running fully updated Vista Home Premium systems, complete with SP1 and all of the patches, but I do not have the TV pack installed.  My video cards are an ATI HD2600XT and an ATI 3870, both with Catalyst 8.7 installed.

I am using Vista Ultimate SP1. Catalyst 8.8. No TV pack (not available here in the Netherlands). My videocard is the onboard ATI3200 (Gigabyte 780G GA-MA78GM-S2H).

I will try more later on this evening!

I have a G35 on-board GPU. DXVAChecker does not give me the option to select "Video acceleration setting...", its greyed out.

How do I set UseBT601CSC? Do I need to for my GPU?

Thanks

Ben

EBH:

I have a G35 on-board GPU. DXVAChecker does not give me the option to select "Video acceleration setting...", its greyed out.

How do I set UseBT601CSC? Do I need to for my GPU?

Thanks

Ben

UseBT601CSC is specific to ATI video solutions.

Hopefully Intel understands that SD video uses BT.601 and HD uses BT.709 and defaults to producing correct grey levels out of the box.

Nvidia does (use BT.601 for SD - without any registry hacks needed), although in my experience Nvidia cards are simply not capable of producing consistent and calibrated grey levels with all software (with Nvidia cards, the grey levels change depending on the software and/or rederer in use).  I found Nvidia cards worked well for Media Center, but Media Player and PowerDVD produce incorrect grey levels unless I use the Nvidia control panel to recalibrate - and then Media Center produced incorrect grey levels (note I am running Vista).

Have you tried running any video calibration source video on your Intel system?

bryanb:

Does the TV Pack offer any improvements to video quality, specifically deinterlacing?  I believe it uses a different decoder than the standard Vista Media Center decoder.

There are minor noticeable differences in the image quality between the Vista RTM, Vista SP1 and Fiji MPEG-2 decoders, but I can't really say any one specifically looked better than the others for playback (I actually haven't tried the RTM Fiji decoder, but I assume it is similar (other than no h.264) to the beta decoders).

One thing that does differ significantly between the 3 is how quickly the image is restored after pressing "skip", "replay", or stop/play when watching HD Recorded TV (at least with digitally recorded HD Recorded TV, using FireSTB to record it).  With the original RTM version, the image restored immediately.  With the SP1 decoder, the screen would most of the time go black and pixelated for about 1/2 a second or more.  With Fiji, the screen would often go black and pixelated for a little less than 1/2 a second and sometimes would produce an image right away.

I've also tried verious Cyberlink MPEG-2 decoders as well as Nvidia's DVD decoders.  All of them produce similar image quality (IMO and with my ATI 2600/3870 video cards), but ALL of these 3rd party decoders instantly produce an image following a skip, replay, or stop/play.  The downside is ALL of the 3rd party decoders seem to have issues somewhere (for example possibly not being able to skip chapters on DVDs, or not being able to FF/RW with some content, etc.).

So far, I prefer the original Vista RTM decoder (but I am currently running the official SP1 decoder because I'm trying to figure out why my Media Center keeps crashing when trying to play HD content - even with a 100% fresh install, fully updated, and now it has started crashing again after installing PowerDVD Ultra).

One thing I should point out is these days almost all of the video processing is done through hardware DXVA, and not using a software decoder.  Essentially the decoder sends the video to the video card and asks the card to do something with it (decode it, scale it, deinterlace, etc.).  Since all of the decoders I have talked about almost entirely use DXVA for all video processing, it is not surprising that the image quality is very similar between them all.  For Media Center, I would say in general we are better off to simply stick with the default Microsoft decoder.

HT Slider

I have an Nvidia 8500GT.  with the newest beta drivers, you can define the video levels from 16-235 or 0-255.  When I choose 0-255, the setup video in VMC (the one with the moving "X") the X does not show up.  when I choose 16-235 I can see it.  However, I was watching a BluRay Movie in Arcsoft and blacks were way off, as in no shadow detail at all in darker areas.  I switched back to 16-235 and it works fine. I'm confused at the results and wonder if you have any experience with these issues.  You seem to be "the man" when it comes to video cards.

Maybe I'm not understanding something either, but I thought it important for the card to pass BTB and WTW.

Montyward:

HT Slider

I have an Nvidia 8500GT.  with the newest beta drivers, you can define the video levels from 16-235 or 0-255.  When I choose 0-255, the setup video in VMC (the one with the moving "X") the X does not show up.  when I choose 16-235 I can see it.  However, I was watching a BluRay Movie in Arcsoft and blacks were way off, as in no shadow detail at all in darker areas.  I switched back to 16-235 and it works fine. I'm confused at the results and wonder if you have any experience with these issues.  You seem to be "the man" when it comes to video cards.

Maybe I'm not understanding something either, but I thought it important for the card to pass BTB and WTW.

I'm glad to hear at least Nvidia has added this capability.  Hopefully the "other" video device manufacturers will follow their lead.

From your description, it sounds like this new setting allows you to select the output video level.  If you have an HDTV hooked up, you would want this set to 16-235 (BT.709).  If you have a PC monitor hooked up, you would want this set to 0-255 (sRGB).  I suspect Nvidia will still default to these (when it interprets the display correctly), but this new setting probably allows us to override the setting as required for some displays.

Your example above sounds like it is doing the right thing (assuming you have an HDTV hooked up; or a monitor that is operating in HDMI/YCbCr mode).  I'll try to explain why below, but essentially you want to calibrate your system so the moving X is "just" visible (not invisible) in the calibration test you used.  When you couldn't see the X, you were loosing a lot of darker scene detail.

I'm trying to think of a way to explain my thoughts without adding confusion to this whole situation...(and it is very confusing...)

Sources:

• Standard video sources, such as analog and digital TV Tuner cards, DVDs, Bluray, HD-DVD, and other digitally captured video streams all work essentially with the range 16-235 for grey/color levels (with RGB this is 16-235 for red, 16-235 for green, and 16-235 for blue).
• For video, everything less than 16 is considered BTB (blacker than black) and everything above 235 is considered WTW (whiter than white).
• Note that with regular video, there is actually a full range of 0-255 communicated, it is just that only 16-235 is intended to be visible.
• Photographs, PC applications, video games, Internet browsing, etc. all work with the range of 0-255 for grey/color levels.

PC processing:

• Although this isn't strictly true, in general and from a regular end users point of view, PCs process everything into an sRGB colorspace with 0-255 levels.  In other words the original video range of 16-235 is expanded into 0-255.
• Note that since video content starts off with video levels (16-235) and this is then converted to sRGB (0-255), that any BTB and WTW is typically lost.
• When I say "any BTB and WTW is typically lost" I mean 0-16 becomes 0 and 235-255 becomes 255 after the expansion.
• Some hard core video enthusiasts prefer to use special codecs (like FFDShow) and configure them so video expansion does not take place during video processing.  This way BTB and WTW is maintained along with the visible range of 16-235.
• Also, since all of the processing (including output) is performed by the video card these days, it would be possible for BTB and WTW to be maintained if the video card/driver was designed to maintain it (I know my ATI 3870 does not).
• Note that to me loosing BTB and WTW doesn't matter at all.  My TV would never be calibrated to see it, so I don't loose anything.  However loosing BTB and WTW does make it so some calibration videos do not work (that rely on BTB and WTW).

Output to a display:

• If an HDTV is used, the video card needs to compress and convert the sRGB into whatever the HDTV requires.  Most newer digital HDTVs require YCbCr (not RGB) with a 16-235 range.  Most older HDTVs that support digital inputs (DVI) require RGB with a 16-235 range.
• If a PC monitor is used, the video card needs to send it the full range sRGB (0-255).
• One glitch is right now video cards do not properly support older HDTVs with digital inputs.  My Toshiba 51X83 is an example of a 51" HDTV with a digital DVI port (that includes HDCP content protection) and video cards always drive it incorrectly by sending RGB 0-255 to it.
• By adding an output toggle in the video driver, I would be able to force the video card to use 16-235 and resolve many  issues.
• One thing to consider here if we compare the original source where 16-235 was visible out of an original 0-255 range to the final output, out final output is now truly a 16-235 range without any BTB or WTW.
• Running a few number through from the source video to what is sent to your HDTV:  16 ends up being 16, 17 ends up being 17, but 15 ends up being 16, 10 ends up being 16, 5 ends up being 16, etc.
• Here is where things get a little messed up - calibration test patterns.  Video test patters used to calibrate grey levels typically show objects slightly within BTB and WTW.  Normally we would calibrate so these BTB and WTW objects are "just" INVISIBLE.  The problem is that PCs typically loose BTB and WTW during the video processing stage.  This means that for grey level test patters to work on a PC, we either need the PC to be setup so it doesn't loose BTB and WTW, or we need video test patterns that "only" use the 16-235 range.  In other words, 16 is black and 235 is white. Further to this, the X should be "just" VISIBLE if calibrated correctly (since there is only one true "black" from a PC, the X is actually brighter than black).  If you can't see the X, your blacks are too dark. 
• In other words, when you selected 0-255 for the output, the reason the X was invisible was because your display needs a 16-235 "visible range".

I hope this helps.....

I guess the biggest problem is that blacks looked too dark in Arcsoft (no detail) while being okay in VMC, or vice versa.

My TV is an older Samsung DLP and I'm connecting via HDMI.  My video card also has the option to change from RGB to YCbCr, currently set at RGB.  If I set it at YCBCr then perhaps the problem will be fixed since it will pass on the proper video level. 

Thanks for your expertise, I think I understand what is going on.  I have always calibrated it to just hide the moving X, so I will keep it a bit brighter than I have in the past and see how it looks.

Montyward:

I guess the biggest problem is that blacks looked too dark in Arcsoft (no detail) while being okay in VMC, or vice versa.

My TV is an older Samsung DLP and I'm connecting via HDMI.  My video card also has the option to change from RGB to YCbCr, currently set at RGB.  If I set it at YCBCr then perhaps the problem will be fixed since it will pass on the proper video level. 

Thanks for your expertise, I think I understand what is going on.  I have always calibrated it to just hide the moving X, so I will keep it a bit brighter than I have in the past and see how it looks.

I found I was not able to get the correct grey levels in both Media Center and PowerDVD Ultra simultaneously with an Nvidia card.  No matter what settings I used, I could only get one or the other in calibration.  I wonder if Arcsoft has the same issue with Nvidia cards?  Note that for some (ridiculous) reason PC video cards (both ATI and Nvidia at least) insist on driving my HDTV with RGB 0-255 (sRGB).  My HDTV has a DVI connection on it (no HDMI) and I have since discovered that every single person I've talked to who has an HDTV with a DVI port has this same issue (I really dug into this issue, even going so far as ensuring my EDID was correct and I even tried a fresh Vista install as well as spoke to both ATI and Nvidia about it + sent in detailed bug reports requesting both ATI and Nvidia add the ability to select YCbCr, RGB 0-255, or RGB 16-235 for digital output).

I have been told that Nvidia cards (in the past at least) do correctly use YCbCr with HDTVs with HDMI ports plus they produce correct grey levels between applications (again only if HDMI is used).

I suggest you try driving your HDTV with YCbCr with a 16-235 range (the standard range for YCbCr) and see how things look.  This is what HDTVs with HDMI ports on them expect as default (most will also accept RGB 16-235 and some can be tweaked in the settings to accept RGB 0-255).

Burn yourself a Bluray and/or HD-DVD calibration disk and use that to test Arcsoft's performance and compare it to Media Center.  My preference is to use a calibration DVD to check "Media Center's calibration", but you can use the moving X (note that the white shirt video will calibrate for white at 255, not 235)

I have DVE for Blu Ray on order and I will check it out.  Changing colorspace to YCbCr will be the first thing I do, as I know that it has been set at RGB. 

Hopefully I get some continuity between programs.