Desktop settings impact playback quality?

[tch65721]

Simple question.
I have an older 65" Mits RP that does 480i/480p/1080i only.
When the desktop is set so that it is usable (480i) playback of a Mpeg2 HD recording is smooth using VMR9 and Hardware acceleration. When the desktop is set at 1080i the playback stutters or "jerks" although the PQ seems a bit better. So the question; Do desktop settings impact Mpeg2 playback?

[cummings66]

In that context yes. Your graphics card and CPU has to work harder to display 1080i vs 480i and so what you seen is possible.

[tch65721]

Originally Posted by cummings66

In that context yes. Your graphics card and CPU has to work harder to display 1080i vs 480i and so what you seen is possible.

Huh?? So desktop settings determine sage playback quality?

[Mahoney]

Yes - if you set the desktop to 1080i, you are asking the computer to upscale the video from 480i to 1080i, and kick out a 1080i signal which is itself more taxing. So it's having to do the extra work to do that upscaling and to display the picture.

Sage doesn't dynamically drop the desktop resolution to the resolution of the video you are playing.

[tch65721]

Originally Posted by Mahoney

Yes - if you set the desktop to 1080i, you are asking the computer to upscale the video from 480i to 1080i, and kick out a 1080i signal which is itself more taxing. So it's having to do the extra work to do that upscaling and to display the picture.

Sorry, I don't understand. Did you miss that I said in my first post this was a Mpeg 2 HD file? Specifically, NBC HD OTA (1080i) captured with Vbox151/Sage with Sage quality setting at "Mpeg 2 Max Quality". I don't see why that would have to upscale.

You're not saying that Sage captures HD sources at 480i are you? That would truly suck.

What I see with the 1080i desktop is the action jumping ahead a bit, like a stutter. I think I'm seeing dropped frames. 480i desktop is perfectly smooth playback.

[Mahoney]

I missed your "HD" comment. You are right, if you are capturing HD then you are capturing whatever is broadcast. Sage's capture quality settings are irrelevant when capturing a digital signal, incidentally.

I'm now firmly guessing, but my guess is that your computer isn't up to deinterlacing 1080i. One of the irritating features of windows video playback is that even if you set the desktop resolution to 1080i and play back a 1080i file, Windows insists that the video is deinterlaced to 1080p and then reinterlaces it to output 1080i again.

It may be that when you set the desktop to 480i, the 1080i signal is downscaled to 480i prior to deinterlacing - and of course deinterlacing a 480i signal requires less horsepower than deinterlacing a 1080i signal.

[tch65721]

Originally Posted by Mahoney

I'm now firmly guessing, but my guess is that your computer isn't up to deinterlacing 1080i. One of the irritating features of windows video playback is that even if you set the desktop resolution to 1080i and play back a 1080i file, Windows insists that the video is deinterlaced to 1080p and then reinterlaces it to output 1080i again.

Whoa, that is amazingly stupid. I had no idea.
Yeah, my box may be too old. Althon XP 64 3200+, 1 meg ram, and a 6600GT.

[stanger89]

Originally Posted by tch65721

Sorry, I don't understand. Did you miss that I said in my first post this was a Mpeg 2 HD file? Specifically, NBC HD OTA (1080i) captured with Vbox151/Sage with Sage quality setting at "Mpeg 2 Max Quality". I don't see why that would have to upscale.

I too missed the HD comment, but that makes it all the more true. When you play video on a PC, everything is scaled to your desktop resolution. So when you play a 1080i HD recording and you have your desktop set to 480i, it's downscaled to 480i.

Outputting 1080i will be a significant improvement.

You're not saying that Sage captures HD sources at 480i are you? That would truly suck.

No, but if your resolution is set to 480i, then your graphics card is scaling to 480i on playback.

What I see with the 1080i desktop is the action jumping ahead a bit, like a stutter. I think I'm seeing dropped frames. 480i desktop is perfectly smooth playback.

Try enabling Fullscreen Exclusive Mode. Most nVidia cards have trouble with VMR9 at high resolutions without running in FSE mode. At least they used to.

[tch65721]

Originally Posted by stanger89

Outputting 1080i will be a significant improvement.

Not as much as you might think. If that is really 480i, I'm impressed. It looks great. There is a tiny difference in detail I can see switching back and forth but it isn't that much. It might be more apparent If I could see a side-by-side comparison.

Try enabling Fullscreen Exclusive Mode. Most nVidia cards have trouble with VMR9 at high resolutions without running in FSE mode. At least they used to.

You hit the nail on the head there. Tried FSE and works great. It might drop a frame now and then but only 2 or 3 times in an hour not every few seconds. Stunning improvement.
Funny thing is I tried FSE before and that Sage icon spun like crazy and computer finally froze... I had to reboot. I have no idea what changed so it works now but I'm sticking with this. Thanks!

[stanger89]

Originally Posted by tch65721

Not as much as you might think. If that is really 480i, I'm impressed. It looks great. There is a tiny difference in detail I can see switching back and forth but it isn't that much. It might be more apparent If I could see a side-by-side comparison.

Actually I agree, downconverted HD looks remarkably good.

You hit the nail on the head there. Tried FSE and works great. It might drop a frame now and then but only 2 or 3 times in an hour not every few seconds. Stunning improvement.

Might want to look at reclock for that. What you're seeing now might be the renderer dropping frames to keep video in sync with audio. Reclock does the reverse (which is basically unnoticable).

Funny thing is I tried FSE before and that Sage icon spun like crazy and computer finally froze... I had to reboot. I have no idea what changed so it works now but I'm sticking with this. Thanks!

Glad it's working

[bcjenkins]

Originally Posted by tch65721

Whoa, that is amazingly stupid. I had no idea.
Yeah, my box may be too old. Althon XP 64 3200+, 1 meg ram, and a 6600GT.

Proc and Video look okay, but I would add more memory..

I was running a 6600GT @ 1080i output using a 2.8 Ghz P4 HT. No issues.

Although, that was v 5. I am now using that box as a dedicated server with a faster client machine.

B

[tch65721]

Originally Posted by bcjenkins

Proc and Video look okay, but I would add more memory..

I'll give reclock a try stanger89. Thanks for all the tips.

[traker1001]

Althon XP 64 3200+, 1 meg ram, and a 6600GT

Yeah, 1meg of ram ain't much!