HD clips not impressing me

[oddball]

I have a NEC 20WGX2 20" LCD display that can handle 1680x1050 res. I thought this would be good enough to test a few HD clips on even though they are 1080P.

But thus far all the clips I have looked at in WMV, Quicktime, H.264 and MPEG2 .TS files look somehow lacking. I am outputing to the screen using a Nvidia 6600GT through the DVI out. I also have installed the Purevideo decoder and a recent build of ffdshow.

What I am seeing is higher resolution video but not neccessarily higher quality. In fact what I am seeing is large amounts of posterisation which makes the image look like it's been encoded in 8bit color at times. The color banding is very obvious. No smooth blends from one shade to another.

Can anyone tell me if this is normal? If so then I am shocked. Is it simply a case of the bitrate being too low in these HD clips? Too much compression?

I have tried VMR7/9 (Slow and juddery on this AMD XP 3200) and standard overlay.

I'm a bit confused as to why it does not look as great as everyone has hyped it up to be.

Example capture below. Note the gradiation in the fog above her. This is not the result of the JPG compression this is in the actual HD trailer.

[dbzgundam]

I have a NEC 20WGX2 20" LCD display that can handle 1680x1050 res. I thought this would be good enough to test a few HD clips on even though they are 1080P.
Try a CRT, and then calibrate your LCD as best you can.

But thus far all the clips I have looked at in WMV, Quicktime, H.264 and MPEG2 .TS files look somehow lacking. I am outputing to the screen using a Nvidia 6600GT through the DVI out. I also have installed the Purevideo decoder and a recent build of ffdshow.
Most HD clips on the web suck, it's true. From what many reviewers have said, the upcoming HD formats (HD-DVD/Blu-Ray) show vast improvements over things such as HDTV broadcasts, Quicktime trailers, and WMV9 videos

What I am seeing is higher resolution video but not neccessarily higher quality. In fact what I am seeing is large amounts of posterisation which makes the image look like it's been encoded in 8bit color at times.
Because it is.

Can anyone tell me if this is normal? If so then I am shocked. Is it simply a case of the bitrate being too low in these HD clips? Too much compression?

I have tried VMR7/9 (Slow and juddery on this AMD XP 3200) and standard overlay.

I'm a bit confused as to why it does not look as great as everyone has hyped it up to be.

It's normal, but I'm sure it is also being amplified by your LCD display.

[Eeknay]

Those Quicktime "HD" trailers all have terrible banding. It's been that way as long as I can remember.. Best bet for HD trailers is more akin to what they show on channels like HDNet, usually 1080i at high bitrates (~18Mbit/s).

[Pookie]

Depends on the quality of the source and the quality (and type) of encoding:

http://fileserver1.jpghosting.com/images/tn_kfh_76cdc1be985a6111813d778fce0f041e.png (http://fileserver1.jpghosting.com/images/kfh_76cdc1be985a6111813d778fce0f041e.png)

vs

http://fileserver1.jpghosting.com/images/tn_j2_69c359eeceaa4eaee51a7988a8ac3296.png (http://fileserver1.jpghosting.com/images/j2_69c359eeceaa4eaee51a7988a8ac3296.png)

[AlexeyS]

Most HD clips on the web suck, it's true.
Agree. Mostly because DivX, WMV and some other codecs can't keep high resolution of HD video.

[CruNcher]

http://www.cineon.com/conv_10to8bit.php
read this to understand why this banding occurs in the quicktime trailers

also this http://www.cineform.com/products/ProspectHD.htm#10bit and that http://www.cirquedigital.com/howto/color_tutorial.html

[mike_lee]

The only HD worth anything now is the porn and it's shockingly good. . . I'm told.

(OK now I'll finally get PMs :-)

[oddball]

OK managed to view something that actually looks good! A sample clip of Shrek in 1920x1080i. However to decode it at a decent speed with no glitches I had to use Nvidia's Purevideo with hardware acceleration. ffdshow is *CRAP* at decoding HD MPEG2.

I wish someone would optimize the MPEG2/1 decoder libraries in ffdshow :(

[mike_lee]

I'm curious why you feel it's necessary to make ffdshow work with mpeg2 since you have purevideo? I find the ffdhow filters adequate at best. (ffdshow's strength to me is in it's various processing abilities)

[oddball]

You answered your own question. The various processing options like adding borders etc.

[CruNcher]

(ffdshow's strength to me is in it's various processing abilities)
that you can't use if you wan't hardware accelerated playback
and nobody yet did a interface for ffdshow (libavcodec) to support DXVA and never will be because it's a painfull work

[mike_lee]

Can't you just change it's merit to preferred so it is always added to the filter chain? That's what I do, so when my purevideo decoder is up so is ffdshow and I can apply a color preset.

[oddball]

Can't you just change it's merit to preferred so it is always added to the filter chain? That's what I do, so when my purevideo decoder is up so is ffdshow and I can apply a color preset.

Detailed explanation please.

[mike_lee]

ffdshow >
video decoder configuration >|
info and debug>
debug> change slider (merit) to high or very high
(not real confident on this method, i do it but I also add the filter to my external filers (below)


method 2
media player classic >
options>
external filters>
add ffdshow and set it to preferred

[oddball]

Does not seem to work for me even in MPC. It uses the ffdshow audio decoder but not for video. Only Nvidia video decoder is shown. If I set it to ffdshow as the codec for MPEG2 it plays it with ffdshow but not Purevideo so I lose hardware acceleration.

[sigmaris]

After the PureVideo system has decoded the MPEG2 stream, the actual picture data is in the GFX card's memory (because it was decoded by the GPU). The video renderer then "arranges" with the GFX card to have it display this picture data on screen, without moving the data back into system memory. The GPU can in some cases also deinterlace the decoded picture.

To process the decoded picture with FFDshow (to crop, resize, deinterlace) it needs to be worked on by the CPU. This would require copying the decoded picture data back to the system memory so the CPU could work on it. This would be very slow and negate any performance benefits gained by using the GPU to offload the decoding.

And this is why even the PureVideo decoder will fall back to decoding MPEG2 (or H.264 or whatever) using the CPU alone, if the next filter it is feeding is not a video renderer that it can "negotiate" with to present the picture data from its location in the GFX card memory.

[oddball]

Which sucks bigtime. I like to be able to reduce the overscan on my TV out using the borders option in ffdshow. However the inbuilt MPEG3 libv decoder is MUCH too slow to decode a 1920x1080i .ts file unless you have a really fast system. If I use the Purevideo decoder it hardly makes a dent in my AMD 3200 XP processor.

I am looking for a workaround but from you just described it appears there is none :(

[CruNcher]

exactly, sigmaris very well explained thx so now everyone is gonna understand why it's impossible to Manipulate anything in Hardware accellerated mode from outside but their is a possibility ;) and thats VMR9 Renderless you can apply shaders onto the Stream and Manipulate it that way more problematic will be getting the data outside of the GPU into a stream.

[mike_lee]

as I was installing the new ffdshow I remembered one thing you must do to make it always come up.

codecs
raw video
(choose) all supported

[oddball]

That works. But it still pulls my system down to it's knee's. Oh well. Will just have to do without for now.

[mike_lee]

That works. But it still pulls my system down to it's knee's. Oh well. Will just have to do without for now.

Oh that's a new problem from the start. I had the same issue it took me days and I have no idea how I eventually fixed it. It was one of these 2 things.

Hyper threading had been turned off and I changed various bios settings.

I control the codecs I use by listing them in external filters in ffdshow, and I disabled all the useless codecs (don't delete them or your pc will crash disable them with the media player classic utility or radlight (something like that) . wmv9 was using 35% CPU I got it down to 4% (my PC is brand new, so maybe it would be 80% on my old pc)

Get GraphEdit and run the clip, you'll see it will only use 2-5% cpu, GraphEdit will be useful to you. I will be gone for 2 days but I'll check this message when I get back.

[oddball]

Yes I use graphedit to see what filters are being used. However if you see my other thread about decoding MPEG2 at 1080i I have another problem. I found for MPEG4 stuff CoreAVC is absolutely astounding. Very well coded decoder.