framerate frustration: slow preview / high cpu use

[Rob Mack]

Well, even though my CPU is faster, it really shouldn’t be *that* fast just for this activity. You really just have a stretch of PAL DV playing. Vegas doesn’t need *that* much power to play straight DV25.

In task manager, is it Vegas that’s running at 98%? I’d assume it is but you’d want to make sure.

What else…Scopes running? Some sort of preview overlay? None of this accounts for that much CPU overhead…

Before this current CPU I was using an Ath64 3800 and never saw this sort of behavior in Vegas 7. But then, I’m in NTSC land so I hadn’t tried a PAL DV clip.

The output over firewire option should tell you something. If Vegas says it’s re-rendering then there’s something more going on.

What’s your preview ram set to? set it down to 16MB and see what happens?

Rob Mack

[Arthur Bueno]

Thanks for thinking this over Rob.
It is Vegas taking up almost all CPU power. Watching the task manager (performance tab) I can clearly see how as soon as I preview to a full size preview screen or the secondary monitor, the cpu usage rises.

You mention something that I don’t understand: you wrote “if you are seeing the message Preview on External Monitor (Frame Recompressed) then it’s a sure sign that what you are previewing is not just straight DV25”

Under Preferences/Preview Device there is an option “Recompress Edited Frames”.
If I put that off and playback through firewire, preview is fine and Vegas takes only about 14% CPU. The preview screen then says: “preview on external monitor”.

But with the Recompress option off and playing back to the secondary monitor, the image will show just the first image and won’t move. So in order to playback to a preview window or a secondary computer monitor I seem to be forced to activate the the “recompress edited frames” option. (preview window then says: frame recompressed).

[Arthur Bueno]

and to reply to your other questions: no scopes, no preview overlay, 100% track opacity, varied Ram to anything from 0 to 250 mb with no success.
In my last try though (with ram set to 16) preview full suddenly took only about 85 % cpu, an improvement already.

[Rob Mack]

It doesn’t sound like preview ram is an issue, but just so you know, if you set it too high you’ll force Windows to start swapping as you play because Vegas constantly caches frames in an attempt to improve subsequent playback.

Okay, on to the “recompress edited frames” idea. The basic idea is that with “recompress edited frames” turned on, and while previewing over firewire, you should see a message in the (local) preview window if frames are being recompressed. If you’ve got straight DV25 on the timeline and you’re previewing over firewire then you shouldn’t see that message because Vegas can just output what’s on the timeline without rendering.

What you’re doing is the inverse of what I’m talking about but that’s okay because it still tells us something. With “recompress” turned off, all that will play out over firewire is the straight DV25. Anything that needs rendering will just not play. In your case, you turned it off (really not the preferred way to run) and everything plays over firewire, confirming that you have straight DV25 with no rendering involved. So we’ve proved that there’s no rendering set as mediaFX, TrackFX, or OutputFX.

Conversely, your preview to secondary display stops playing. What that means I don’t know, but I assume it means that Vegas has to render to play on your secondary display. That seems odd to me but I’ll go try it out here…

(Time passes…) Okay. When previewing straight PAL DV25 to a secondary display I get about 9% Vegas CPU load (looking at the processes tab of task manager). In the performance tab the total CPU usage is about 16%, so there’s additional sstem load beyond Vegas.

My review settings are:
Preview/Full,
Device=Windows Secondary Display,
Display Mode=Use Current Settings,
Scale Output=off
Apply deinterlace=off
Use color management=off
Recompress=On
Display frames in video preview=off

I’m stumped. You shouldn’t see that much CPU usage from Vegas, even on a slightly slower system (and your’s isn’t really slow). At this point I’d look at taskman’s processes tab just to be sure all that CPU usage was Vegas proper. If not then I’d wonder if your disks or display card are putting an unexpected burden on the system, or if something like antivirus software was scanning the footage as vegas reads it.

Rob Mack

[Rick Mac]

Arthur,

Forgive me if someone has already suggested this ( I have not read the entire thread ). Your CPU ussage is way to high and should not be.
Since you get better framerates going out to external firewire I would be looking very hard at my Video Card Driver. Sounds to me like the problem is there. I would go to system/device manager and see if I have an exclimation mark beside my video card. If no mark I would download the latest drivers for my video card, uninstall my current card. Then rebbot. Do not let plug and play install drivers. Run the installtion program for new drivers. If that does not help try installing another video card if you have one laying around.

Let us know if that helps.

Regards, Rick.

[Arthur Bueno]

Rob, what you tell me about recompression really surprises me. For as long as I know Vegas (since version 3), or for as far as I remember (even on another computer), it allways gave the message “frame recompressed” when I outputted either through firewire or to a secondary monitor.
I might remember it wrong (no I don’t), but it definitely shows the message now (that is: as soon as I set “Options/Preferences/PreviewDevice/Recompress edited frames” to “on”).
I never understood why it was so, since if you play a simple dv file in a simple dv project nothing seems to need recompression.

To sum up some possibile culprits for the high cpu use:
– as Rick Mac suggested it might have something to do with the video driver since cpu use only occurs when playing to a computer monitor. I have a Nvidia 6800GT, updated the driver regularly and last time less than a month ago. Don’t see how I can do better.

– One other possible difference in my workflow: I allways capture with scenalyzer live (I love that program and wouldn’t want to miss it). Just tested playback with a clip captured by the Vegas Capture program, but playback gives the same high CPU use.

– I have a standalone mainconcept dv codec installed to render from VirtualDub (but in Vegas I setting the tag “ignore third party codecs” to on or off makes no difference in playback performance). For testing I just uninstalled the standalone MC-codec, no difference, still around 97 % cpu.

– The project format could be different from the media format, but I checked so many times all the settings of both media and project that I started to have dreams about them (PAL, 25 fps, 720 x 576, lower first, ratio 1.0926), they’re identical.

What I’d really like to know from other users: Am I the only one who

[Arthur Bueno]

sorry, I made a mistake. When outputing through firewire with “recompress edited frames” set to “on” I do indeed NOT get the “frame recompressed” message in the preview window, and the cpu usage is around a acceptable 20%.
So I get that message (and the high cpu use) only when outputting to a computer monitor or preview window.

[Rob Mack]

Arthur,

I also see frame recompressed when outputting to seconadry monitor, but not when playing a straight DV clip out via firewire. The firewire behavior is as it should be. I don’t know about the recompression when playing to the secondary screen, I don’t see the reason for it, assuming its just a frame buffer. Still, for me, Vegas itself is running at 9% CPU. There’s another 6 or 7% on top of that that seems to be the OS.

I’m wondering if the driver for your card is somehow also using the CPU? perhaps there are settings in it’s video overlay control panel, or color correction, or something…

Rob Mack

[Arthur Bueno]

Done some more troubleshooting: I totally uninstalled the drivers for the Nvidia 6800GT (removing all traces of previous installations), and reinstalled again. unfortunatly: no improvement in playback performance.
I then uninstalled the NVidia drivers again, and replaced the card with an old Radeon 9550, with newest drivers. After this playback to computer monitor remained about just as bad, with just as high cpu use.
This seems to rule out the videocard(drivers) as cause for bad playback. (I’ll probably go back to the NVidia card, since it can do GPU rendering for magic bullet plugins, which works ok).

Also tested HDV playback on both cards (m2t file in matching HDV project in V7). They give me around 5fps on to secondary monitor on preview full. Onpreview auto it never goes above something like 18 fps. I’m still wondering what performance other people get from HDV playback with systems like mine, and how they make it workable.