How to Change WTV mpeg2 Decoder WMC7

[richard1980]

The assertion that the GPU hardware is the problem is weak because I have enabled CUVID DxVa/GPU Deinterlacing in LAV, so the GPU is doing the work just like when wmc uses the MS decoder.

CUVID is not DXVA. They are two different things. LAV only offers the ability to hardware accelerate deinterlacing when using CUVID or QuickSync, not DXVA2. Hence the reason the configuration screen says "Hardware/GPU Deinterlacing (CUVID/QS only)" and the option becomes unavailable when you change the hardware decoder to either of the DXVA2 options. This differs from Microsoft's DTV decoder, where hardware deinterlacing is performed via DXVA. So in summary, if you select CUVID or QuickSync you can enable the respective hardware accelerated deinterlacing function, but if you choose not to enable that feature or if you select DXVA as the hardware decoder, deinterlacing is done in software by the CPU.

[barnabas1969]

Anyone can see my system specs by clicking the button next to my username.

Great, thanks for adding your specs. That wasn't there when I posted my original question.

I use the latest whql official drivers...

That might actually be your problem. If you've read some posts here, you know that the "latest WHQL" drivers may cause you some problems. There are several threads here about which drivers work, and which don't.

[barnabas1969]

I don't know what all you guys are arguing about - different decoders render the image differently - that's what they do. The OP is saying he prefers the way LAV decoders decode/the resulting image they display compared to the default MS decoders. If you haven't seen a WTV file decoded with LAV decoders - then you can't say "I don't see the issue" because you have no idea what the image looks like decoded with LAV compared to MS decoders in the first place. You only know what the MS decoded image looks like. The OP is saying that he is seeing more apparent jaggies/artifacts in the MS decoders after seeing what they look like decoded with LAV - not that the MS decoded images are completely jaggy - just that there's a bit and that it is more apparent after viewing the image decoded with LAV and then going back to the MS decoders.

OP - yeah you're f*cked if you wanna use LAV and have copy-flagged content. You're either gonna have to accept/get used to switching back and forth between decoders, or stick with the MS decoders (or give up the flagged content - but I don't think we consider that an option).

I have no comment about which produces the better image, and I have no doubt that some decoders do a better job of deinterlacing, scaling, etc, and that software that uses the CPU can produce different results than software that uses the GPU.

All I know is that my Media Center PC produces a MUCH better image than the SA cable box that I had. I don't see the problems the OP is experiencing. I am using the default decoders.

So... the OP must have something different.

We now know that the OP is using an nVidia GT610. It should work fine. If you're an avid reader here, you should also know that different drivers and different settings can affect the performance of a GPU.

Now, I'm waiting for the answers to my other questions.

[tzr916]

My system specs have been there since I joined this site. Last time they were updated was a few weeks ago when I got a Quad Core processor.

What's funny is, I don't recall asking if anyone else is seeing my symptoms. I don't recall asking for help with Tv settings, driver settings, gpu's, driver versions, etc. I don't recall asking anyone for their opinion of the picture quality they see on their system. I don't recall asking whether changing the wmc decoder is "what I really want to do". I thought my OP was pretty clear. Changing the wmc decoder is exactly what I wanted to do. For some reason I got resistance here so I had to go elsewhere to get the help I was asking for. One person here did reply to my OP properly and provided a helpful link.

[richard1980]

I just looked up the GT 610, and discovered that it's a rebranded GT 520. Coincidentally, AnandTech reviewed the deinterlacing performance of the GT 520..and the review was not good. You can read the review here.

[richard1980]

I'd also like to point out that I initially posted after the initial solution had been posted, and my posts haven't been about whether changing the decoder is the right or wrong thing to do (in fact, I said it was one of 4 possible solutions), but aside from my response to barnabas' "I don't see what you see" post, my posts have been about why there is a difference between the Microsoft DTV decoder and the LAV decoder. Due to the requirement to be able to play copy protected content, I think the solution is very clear: You have to change the GPU.

[staknhalo]

You have to change the GPU.

Using his current GPU, LAV renders TV that is acceptable to him - so no, he doesn't. The problem is no matter what GPU/driver/whatever combo OP has, he will never be happy with the MS decoder after seeing the difference LAV makes in rendering - that's what he is saying but you all seem to be missing.

I assume that you are making the point that a different GPU could improve the MS decoder - and that's valid and true. But OP wants LAV because of the superior IQ it provides based on his current HW (whether you agree/disagree/have even ever seen it - it's superior to him and that's all that matters in his case), that's what this has always been about.

[tzr916]

I just looked up the GT 610, and discovered that it's a rebranded GT 520...

Link?

Would a GT630 be better?

[staknhalo]

I just looked up the GT 610, and discovered that it's a rebranded GT 520...

Link?

It is, you can find sources all over the internet via Google. Nvidia has a bad habit of rebranding.

[richard1980]

You have to change the GPU.

Using his current GPU, LAV renders TV that is acceptable to him - so no, he doesn't.

Did you forget about the part where LAV doesn't work with copy protected content? If you prefer, I'll rephrase: You have to change the GPU or stop watching copy protected content.

The problem is no matter what GPU/driver/whatever combo OP has, he will never be happy with the MS decoder after seeing the difference LAV makes in rendering - that's what he is saying but you all seem to be missing.

I assume that you also might be making the point that a different GPU could improve the MS decoder - and that's valid and true. But OP wants LAV because of the superior IQ it provides (whether you agree/disagree/have even ever seen it - it's superior to him and that's all that matters in his case), that's what this has always been about.

Microsoft's decoder DOES NOT do the deinterlacing. Microsoft's decoder uses DXVA to hand off deinterlacing to the GPU, so the deinterlacing performance when using Microsoft's decoder depends entirely on the quality of the GPU. Changing the GPU changes the deinterlacing quality, and it's entirely possible for a different GPU to match or exceed the deinterlacing quality observed when using LAV.

[staknhalo]

You have to change the GPU or stop watching copy protected content.

I can't argue with that; it's his only other alternative to having to switch between LAV and MS provided constantly, but...

and it's entirely possible for a different GPU to match or exceed the deinterlacing quality observed when using LAV.

...like you said, it's only possible. Not guaranteed. So OP could switch out the GPU just to see no change in PQ on his end; and end up still preferring to use LAV.

Edit: What I'm getting at - I don't think what the OP is seeing is differences in rendering between GPUs (from how I read it), but just the differences in using LAV vs MS & DVXA. So switching out the GPU if that's the case isn't going to do squat.

OP - give switching out the GPU a shot if you feel like it. If it doesn't do anything then like I said on the last page, the only option is to switch decoders when viewing flagged content, or, just end up sticking with the MS defaults.

[richard1980]

I just looked up the GT 610, and discovered that it's a rebranded GT 520...

Link?

It is, you can find sources all over the internet via Google. Nvidia has a bad habit of rebranding.

Agreed. I was actually looking for someone that had reviewed the GT 610's deinterlacing when I ran across a forum post that claimed they were the same GPU...so naturally I started searching for confirmation and found many results confirming it. Just Google "GT 610 vs GT 520".

The GT 630 is a rebranded GT 440. The GT 630 would certainly be better than the GT 610, but whether or not it offers an acceptable level of performance is a different matter.

...like you said, it's only possible. Not guaranteed. So OP could switch out the GPU just to see no change in PQ on his end; and end up still preferring to use LAV.

I have ruled out the possibility of using LAV because it doesn't work with copy protected content and switching decoders all the time is not a viable solution (as was indicated by the OP in post 11). The only remaining solution is to change the GPU (assuming changing the driver and/or settings doesn't work...according to the AnandTech review I previously posted, NVIDIA stated that the poor deinterlacing performance was due to hardware limitations, so changing the driver/settings isn't going to help). Obviously the chosen GPU should perform to the standard the OP wants, whether that be the same as or better than what he sees with LAV, but if he can't find a suitable GPU that performs to his liking, he'll have to compromise.

Edit: What I'm getting at - I don't think what the OP is seeing is differences in rendering between GPUs (from how I read it), but just the differences in using LAV vs MS & DVXA. So switching out the GPU if that's the case isn't going to do squat.

You're right...he isn't seeing difference in rendering between GPUs. The way he's got it set up, what he's seeing is the difference between two different hardware acceleration technologies within the same GPU. Neither LAV nor Microsoft's decoder are doing the deinterlacing...both are handing it off to the GPU, but they're doing it in different ways. When LAV is active, it's using the GT 610's CUDA implementation for deinterlacing, and when Microsoft's decoder is active, it's using the GT 610's DXVA implementation. And the reason he's seeing a difference between the two is because the GT 610's CUDA implementation obviously performs better than its DXVA implementation.

[Mike88]

Is there a flow chart that shows how the video and/or audio is handled?

I use WMC7 & an HD6450 video card. What's processed by the CPU & what's processed by the video card?. Some picture adjustments can be made in WMC & some in the AMD Catalyst Control Center. And if LAV filters or other software is used how does that change things?

I've never been able to find a diagram showing how all of this is tied together. Is there such a thing?

[richard1980]

You won't find a single flowchart because the exact process depends on what DXVA functions are built into the GPU and what DXVA functions the decoder is designed to try to offload to the GPU. However, you can gain a general understanding of how DXVA works here. Notably, the following is stated:

Graphics hardware can use the graphics processing unit (GPU) to process uncompressed video images. A video processing device is a software component that encapsulates these functions. Applications can use a video processing device to perform functions such as:

• Deinterlacing and inverse telecine
• Mixing video substreams onto the main video image
• Color adjustment (ProcAmp) and image filtering
• Image scaling
• Color-space conversion
• Alpha blending

A video driver can implement more than one video processing device, to provide different sets of video processing capabilities. Devices are identified by GUID. The following GUIDs are predefined:

• DXVA2_VideoProcBobDevice. This device performs bob deinterlacing.
• DXVA2_VideoProcProgressiveDevice. This device is used if the video contains only progressive frames, with no interlaced frames. (Some video content contains a mix of progressive and interlaced frames. The progressive device cannot be used for this kind of "mixed" video content, because a deinterlacing step is required for the interlaced frames.)

Every graphics driver that supports DXVA video processing must implement at least these two devices. The graphics driver may also provide other devices, which are identified by driver-specific GUIDs. For example, a driver might implement a proprietary deinterlacing algorithm that produces better quality output than bob deinterlacing. Some deinterlacing algorithms may require forward or backward reference pictures from the primary stream. If so, the caller must provide these pictures to the driver in the correct sequence, as described later in this section.

There are two major differences between LAV and Microsoft's DTV decoder:

1. LAV and Microsoft's decoder both support DXVA, but they don't both utilize the same DXVA video processing devices (for example, LAV's DXVA decoder does not offload deinterlacing to the GPU whereas Microsoft's decoder does).
2. LAV supports technologies that Microsoft's decoder doesn't. Microsoft's decoder only supports DXVA, but LAV supports DXVA as well as competing technologies such as NVIDIA's CUDA and Intel's QuickSync.

Ultimately, the problem here is that NVIDIA implemented both CUDA and DXVA into the GT 610, but the deinterlacing algorithm(s) used in their CUDA implementation are superior to those used in their DXVA implementation. NVIDIA could have created the same algorithm(s) for the DXVA side, but obviously they didn't. Instead, they focused more on their own video processing technology, which certainly isn't surprising....after all, CUDA competes with DXVA.

[Mike88]

Thank you for the information. I took a brief look at the link that you provided & will have to read it in detail.

[tzr916]

Coming from years of using OTA HD tuners, Clear Qam HD tuners, Bluray disc playback, and dvd up-scaling, I never saw any picture quality issues using much less GPU power. I chose the GT610 merely because it was cheap, fanless, and had hdmi. Had I known that Win7 WMC cable card was locked into MS decoder with no way to disable DXVA or use other decoders (like all other AV application I've ever used), I would have put more time into GPU research. Easy mistake given the rebadging situation, lack of HQV test results available, and hardly any complaints posted about WMC picture quality vs GPU.

With the GT610, I found that I could:
A. Use MS decoder and be constantly distracted by the crappy video quality
B. Force LAV in WMC- excellent video quality but buggy and no HBO
C. Use an external player with LAV- top notch video quality but more work to get remotes working, not very wife friendly, and no HBO

I decided to try a different GPU. After searching for HQV results, I went with a GT640 fanless. WMC with MS decoder does look much better. Almost 95% of the video defects I was seeing with the GT610 are gone. It's enough to be satisfied (for now). Just very disappointing that WMC decoder is DXVA / locked down and requires so much GPU just to get a decent picture.

[barnabas1969]

Many of us use GT-430 video cards without issue. I wouldn't say that a GT-430 is very powerful.

I've also tested the Radeon HD 6450, and it worked fine. You can find these two graphics cards for less than $50.

Here's one such example:

http://www.newegg.com/Product/Product.a ... 6814121439

[tzr916]

Never been an ATI fan/user.
Chose GT640 based on HQV vs GT430-
http://www.anandtech.com/show/5969/zota ... -review-/6
http://www.anandtech.com/show/3973/nvid ... e-gt-430/4

[jdtayloruk]

I know it’s very old but: http://www.hack7mc.com/2009/04/media-ce ... ows-7.html website is gone.

Its annoying I can’t get that utility.

[renojim]

Did you try the Wayback Machine?

https://web.archive.org/web/20130601092 ... laces-vmcd