Decoder Confusion

[deria]

Hi,

I've been meaning to ask this for a while, but haven't managed to get around to it.

I use the NVIDIA PureVideo decoder. I have two issues with my setup:

1) Ghosting, for lack of a better term. Its hard to describe, but if I'm watching a show (particularly one with dark areas) I can often see a strange effect on the video. For example, say the screen is showing a person and then fades to black. When it does, I can sort of see a halo or outline of the persons head against the back background.

At first I thought I just had crappy recordings. I'm not sure now, though. I switched to the SageTV built-in decoder, and the ghost is no longer evident (with the same recording). Is there anything I can do to improve this with the NVIDIA decoder?

2) Is there an effective alternative decoder available? I don't mind buying one. My video card isn't even an NVIDIA card anymore (its an ATI X1600). When I bought the card, it said it supported Avivo which I assumed to mean would at least include an mpeg decoder, but it apparently doesn't. What do I need to do to get a decoder that uses the hardware acceleration features of the video card?

EDIT:

I should mention that I'm using Windows Vista, and VMR9. I tried using Overlay, and even though it looks better (to me) it force Vista into the basic UI mode which isn't cool.

[Taddeusz]

I'm not sure there is a way to correct it but I've noticed that under VMR9 the PureVideo decoder is not using the correct black and white levels and comes out very color banded compared to when it's running in overlay mode. This is easy to fix with older nvidia cards because you can drop back to an older video driver that doesn't do that under VMR9.

I mainly watch everything on my SDTV now running through a MediaMVP. My SageTV box is now merely a server and is no longer also used as a client. A much better situation for me since I don't need to have the noisey computer next to the TV.

My only real suggestion for you is to put it into overlay mode and see how you like it. AFAIK nvidia doesn't seem to have any plans for further development of their PureVideo decoder, particularly to support Vista Media Center. I would consider that rather reliable considering the latest available version is now almost a year old.

I believe the PureVideo decoder, for the most part, was a jump start so that people could immediately take advantage of PureVideo on their nvidia cards while all the major decoders (PowerDVD, WinDVD, etc) worked to take advantage of their acceleration. Now that they all both support PureVideo and consequently AVIVO there is no need for them to continue development of their decoder.

BTW, AVIVO is merely the name of ATI's built-in video acceleration technology. It doesn't imply a decoder but is only a platform for other's to use to better accelerate video playback on their video cards. A decoder that is written to take advantage of AVIVO is required in order to take advantage of those capabilities.

[kricker]

Ive been using the Open Source decoder you can find a link to here. I do not think it takes advantage of any hardware acceleration though. In my experience though it looks darn good.

[Mahoney]

The PureVideo Decoder isn't your problem. I saw exactly the same thing with a ATI X1600 using the ATI/CyberLink decoders.

If the decoder uses hardware acceleration (as the PureVideo decoder does) then most of the image quality is decided by the hardware, not the decoder. The AVIVO stuff is in the hardware, and the problem we both have seems to be a feature of it, in some instances at least (perhaps it's X1600 specific?). I raised a bug and tried to get them to sort it, but ran out of steam on chasing it up. Now I've got an nVidia card, which doesn't have the issue.

Just out of interest, are you in a PAL country? (I am, and I wondered if it was a case of ATI not having much experience with anything other than NTSC.)

[Taddeusz]

As I said, I had this same problem on an nvidia card, an AGP 7600GS. For me, switching back to the last 80 series drivers fixed my problem. nvidia did something in their later drivers that screwed up the output white and black levels.

For ATI cards I would recommend trying a different decoder. The Cyberlink PowerDVD decoder is very good and takes advantage of AVIVO. I personally think Cyberlink's decoder looks great, but everyone's mileage varies. Also take note that the newest version of PowerDVD is written to work with Vista. Which PureVideo is NOT and probably never will be.

I don't believe nvidia has any plans to update their PureVideo Decoder to fix bugs on it. Particularly for ATI/AMD cards. And at the same time why should ATI/AMD work to fix bugs with their competitor's decoder? It doesn't even support AVIVO acceleration.

[Mahoney]

As I said, I had this same problem on an nvidia card

No, you didn't. You said "I've noticed that under VMR9 the PureVideo decoder is not using the correct black and white levels and comes out very color banded compared to when it's running in overlay mode".

That doesn't sound like what he is describing or I saw. It's more like a shadow after movement - a bit like mouse trails, though fading, when a light thing moves or disappears against dark backgrounds. I see nothing like it using the latest nVidia decoders with an 8800GTS or a 6150.

The Cyberlink PowerDVD decoder is very good and takes advantage of AVIVO

This is the precise decoder with which I saw this issue.

why should ATI/AMD work to fix bugs with their competitor's decoder?

Who said anything about ATI fixing bugs in a competitor's decoder? I was using an X1600 with the ATI/Cyberlink decoder. As I said.

It doesn't even support AVIVO acceleration.

The PureVideo decoder supports hardware acceleration, and if you are using an X1600 hardware acceleration equals AVIVO. Unless you positively know otherwise, my understanding is that decoders that use hardware acceleration are a pretty thin layer using a common interface, and so any decoder that uses hardware acceleration will get the benefits of AVIVO when you use it with an X1x00.

[deria]

Hm, so the problem might be the X1600 instead of the PureVideo decoder. Thats.... not good. I don't see the problem with the SageTV decoder, so in the meantime I guess I'll use that. The only trouble with the SageTV decoder is that its not very tolerant of errors in the .mpg file (and because I'm using Firewire recording, I often have errors in the .mpg file).

[stanger89]

Originally Posted by Taddeusz

I'm not sure there is a way to correct it but I've noticed that under VMR9 the PureVideo decoder is not using the correct black and white levels and comes out very color banded compared to when it's running in overlay mode. This is easy to fix with older nvidia cards because you can drop back to an older video driver that doesn't do that under VMR9.

I'm getting the correct levels with the 93.71 drivers and latest nVidia decoders on my 6800.

[kricker]

Originally Posted by deria

Hm, so the problem might be the X1600 instead of the PureVideo decoder. Thats.... not good. I don't see the problem with the SageTV decoder, so in the meantime I guess I'll use that. The only trouble with the SageTV decoder is that its not very tolerant of errors in the .mpg file (and because I'm using Firewire recording, I often have errors in the .mpg file).

Try the decoder I linked to above. I find it much much better then the Sage decoder. If you don't like it you can remove it, it uninstalls very cleanly.

[Taddeusz]

Originally Posted by Mahoney

The PureVideo decoder supports hardware acceleration, and if you are using an X1600 hardware acceleration equals AVIVO. Unless you positively know otherwise, my understanding is that decoders that use hardware acceleration are a pretty thin layer using a common interface, and so any decoder that uses hardware acceleration will get the benefits of AVIVO when you use it with an X1x00.

I could always be wrong but it's my understanding that the PureVideo and AVIVO hardware accelerators on the cards are dependent on a compatible decoder not just simply a "hardware decoder." That they have their own unique interfaces. While having a common interface would be ideal I wouldn't expect two competing companies to maintain compatibility with each other on such a fundamental level. I do know that decoders prior to the development of PureVideo and AVIVO but that still have hardware acceleration cannot take advantage of those technologies. They are not written to address the specific interfaces of each.

The PureVideo Decoder is made to do tasks in software if the hardware isn't available to do the job. I personally wouldn't expect the full tilt acceleration from an ATI AVIVO capable card that you would get from an nvidia PureVideo capable card while using the PureVideo Decoder. At the very least the PureVideo Decoder would not be optimized to run on a competing video card.

Again, I could always be wrong. They each could just be acceleration technologies veiled within market speak under a common interface. But unless absolute proof tells me otherwise I'm led to believe that their interfaces are mutually incompatible.

[vvulture]

I am using a ATI x1600pro PCIex card in my client.

From experience, the best combination i have come across is using :

- Catalyst 7.1 or 7.2 ( get them HERE )
- AVIVO 7.4
- Apply TRDenoise registry hack ( see HERE for details ) There's a lot to read, but it's worth it. I have attached the ATI Findreg tool for you. <-- Does not work with Vista
- Use powerDVD 7.3

I ended up with an awesome picture. But i strongly recommend a clean install as well just to be safe.
Oh, and i am also using K-Lite coded package 3.01Full for Divx etc...

cheers

[jprine01]

I'd just like to ad I'm using ATI x1600 HDMI w/Nvidia PureVideo Decoder. The very first day I noticed VERY BAD ghosting and shadows behind stuff (I guess that might be called streaking too?)
All I did was disable hardware acceleration in PureVideo settings and everything looked o.k.

Now I'm trying to get rid of some of the background fuzz on both my computers.
My ATI x1600, and my other computer w/Geforce 8600GTS..
They both show too much compression in the backgrounds (example: sky shot on HD channel, I see sections of the sky that are about the same color grouped into blocks moving back and forth as the screen changes making it look blocky, I guess it could also be described as ants moving around)
I see all this fuzz/ants just watching a dvd full screen in sage on either computer so its not my tuners.
If I compaire a DVD playing in Sagetv w/1920x1080 desktop (1080p TV) resolution vs.
DVD in my stand alone dvd player set on 720p upconversion the DVD player looks at least twice as good.

[stanger89]

Sounds typical of a display miscalibration issue, such a problem will make otherwise unnoticable artifacts obvious.

[samgreco]

Originally Posted by kricker

Ive been using the Open Source decoder you can find a link to here. I do not think it takes advantage of any hardware acceleration though. In my experience though it looks darn good.

Kricker,

I downloaded this codec and installed. Zoom Player sees it fine, but Sage doesn't see it at all. Nor does it see the newest DScaler codec . I'm using Sage 6.1 (latest). Did you do anything with Sage?

Anyone have any ideas?

[deria]

I thought I'd post an update.

The source of the ghosting is the temporal denoising feature of the video card. You can turn it off on Windows XP *only*. On Windows Vista, which is what I'm running, your only option is to disable deinterlacing entirely (which is a terrible idea, don't do it), switch to a decoder that doesn't use the AVIVO features, or buy a video card that doesn't suffer from this issue (ie: NVIDIA).

I'm very disappointed with ATI. The thread that was linked to a few posts above this one talks in-depth about this problem, includes screen shots, and details the 12 month history of the bug.

The final upshot was that ATI ackowledged it is a problem, released a registry hack for Windows XP drivers, and stated that they won't do anything at all about it on Windows Vista.

I'll be buying an NVIDIA card today, and I won't be buying an ATI card again, ever.

[kricker]

Originally Posted by samgreco

Kricker,

I downloaded this codec and installed. Zoom Player sees it fine, but Sage doesn't see it at all. Nor does it see the newest DScaler codec . I'm using Sage 6.1 (latest). Did you do anything with Sage?

Anyone have any ideas?

Yes you need to add lines into the .properties file of Sage or SageClient:

videoframe/additional_video_filters=MPV Decoder Filter

For Dscaler to work you need

videoframe/additional_video_filters=MPV Decoder Filter;Dscaler Mpeg2 Video Decoder

[vvulture]

Originally Posted by deria

I thought I'd post an update.

The source of the ghosting is the temporal denoising feature of the video card. You can turn it off on Windows XP *only*. On Windows Vista, which is what I'm running, your only option is to disable deinterlacing entirely (which is a terrible idea, don't do it), switch to a decoder that doesn't use the AVIVO features, or buy a video card that doesn't suffer from this issue (ie: NVIDIA).

I'm very disappointed with ATI. The thread that was linked to a few posts above this one talks in-depth about this problem, includes screen shots, and details the 12 month history of the bug.

The final upshot was that ATI ackowledged it is a problem, released a registry hack for Windows XP drivers, and stated that they won't do anything at all about it on Windows Vista.

I'll be buying an NVIDIA card today, and I won't be buying an ATI card again, ever.

If you are using the PC as a dedicated Sage rig, why do you need to use Vista ?? Go with XP and apply the patch. It's well worth it...
Regardless, i think that ATI cards have a better picture quality than nVidia for HTPC application.
Like i said, if it's a dedicated HTPC rig, just run XP.

cheers

[samgreco]

Thanks Kricker. Easy. Now to play...

[deria]

Originally Posted by vvulture

If you are using the PC as a dedicated Sage rig, why do you need to use Vista ?? Go with XP and apply the patch. It's well worth it...
Regardless, i think that ATI cards have a better picture quality than nVidia for HTPC application.
Like i said, if it's a dedicated HTPC rig, just run XP.

cheers

Well, primarily I went with Vista becasue thats what the system had on it when it got promoted to PVR (due to the demise of the previous system named PVR).

Beyond that... well, its Vista Ultimate. It wasn't cheap, and it provides alot of functionality above and beyond what Windows XP offers. The problem in this case isn't the operating system, its the video card drivers.

Unfortunately, ATI is not interested in supporting thier cards under Vista.

NVIDIA is better, but it has its own problems (specifically, overscan compensation doesn't work on the NVIDIA drivers under Vista yet).

Its basically six of one, half a dozen of the other when it comes to video cards under Vista. In six months, hopefully things will have improved. For now, I've chosen the lesser of two evils and gone with the NVIDIA. I can live with the overscan since I can adjust it in SageTV and I don't use the desktop for anything else.