Rendering Time related to CPU or Disk

plmdhale wrote on 3/3/2003, 11:16 AM
Have really been enjoying VV4 DV capturing, editing, and making DVD's. Has really helped my hobby - getting grandkids and family activities to the TV screen. The question I have regards rendering time. As an example, I captured 1 hour of video from the DV camcorder. Using Windows 2000 Server with AMD DURON 1200 ghz with 256 meg memory and 7200 rpm IDE Maxtor 80gig with plenty of space, it took about 2 hours to render as 'good' MPEG2. O.K. No big deal, that machine can just set over there and work, I'll do something else. But, after a few days comes the itch to make it better, so my computer shop installs new AMD Athalon 2100 CPU and 1 gig DDR memory, same OS, Same disk drives. So I take it home, load up the same project and select 'render as' again with the same settings expecting better render times, but to my surprise, the render time was still 2 hours, maybe 2 or 3 minutes faster. Is there a VV4 memory available setting I'm missing?? Or is the render time based on the disk drive speed which wasn't changed and is no faster? Any ideas??
Render time seems to be 2 times the amount of video. (Not griping about VV4 here - it certainly performs as advertised, just trying to understand the relationship to the hardware.)

Thanks

Paul Hale

Comments

mikkie wrote on 3/3/2003, 12:06 PM
Harder question then it seems at first blush...

If you're using a compression format that's more CPU intensive, as winmedia 9 for example, then the number of cpu's and their horsepower will matter. It will make a difference with MPEG2 as well, but as you found out, not necessarily something really drastic.

Some has to do with the processor itself, & there are folks that say that rendering video with a P4 instead of an Athlon XP+ makes a difference - remember that most, but not all functions of the XP+ chip are roughly the same as a P4 of the comparable MHz. An Athlon 2100 XP+ is still somewhere around 1.6 GHz I think, so upgrading might not have been as big a jump as you thought.

If you didn't have the motherboard replaced, that would be a factor, as well as which one you're using - some are much faster then others. While total ram is important, it's a bit less so with rendering video IMO. There's also several speeds of DDR available, and faster is better *IF* your motherboard can run at the faster speed this DDR is rated at.

Hard drive speed matters as you have to read a video stream from the drive and re-write it somewhere else. 7200 is nice, but 10,000 obviously is nicer. Also bear in mind that the data has to get to the drive, and there can be quite a few bottlenecks there depending on your set up. Reading from one drive, writing to another on a separate channel helps, & ideally neither drive should be on the same bus as your system drive. Running drives at UDMA 6 is better then UDMA 1, 2, or 3.

Lastly, might be read as herasy here, but there are faster mpeg2 encoders.
cyanide wrote on 3/3/2003, 12:12 PM
It always amazed me that if you doubled your processor speed, say from 500 mz to 1 ghz, you only saw about a 10 - 20% speed increase. If you really want to shorten render times, a dual P4 3 ghx with 1 gig of rambus memory should help quite a bit.
JackHughs wrote on 3/3/2003, 12:39 PM
I think you can eliminate drive speed as a possible cuplrit. Even with the fastest CPU's rendering remains so time intensive that any hard drive should be more than capable of delivering the necessary raw material and receiving the finished product in a timely manner. Now, if you have other applications running simultaneously - each greedily demanding its fair share of CPU cycles, then rendering performance will surely suffer.

JackHughs
GrizzlyIke wrote on 3/3/2003, 1:47 PM
Previous threads indicate that rendering time is related more to the amount of transitions, generated media, etc. This was driven home to me during the following project. I made a nine-window frame using a "veg" file downloaded from Sundance. I filled the eight perimeter frames with video and the center frame with generated media. Total length of clip - 1.0 minute; total rendering time - ten hours, 40 minutes (600 Mhz processor). Made a four-window frame and filled it with stills. Render time was under ten minutes. Hope this makes you feel better.

Grizzly Ike
cyanide wrote on 3/3/2003, 1:54 PM
Actually, a 2-hour render for a 1-hour clip isn't all that bad...
wcoxe1 wrote on 3/3/2003, 3:06 PM
First question:

Did you upgrade your motherboard?

If you didn't you POSSIBLY have a bottleneck there that can not be overcome by increased CPU speed, alone, except under certain circumstances. This is something which I have seen on dozens of occasions in the local computer shop. They are honest enough to tell people that upgrading a CPU doesn't always give the expected results, even with new, faster RAM.

They do the job twice, with no extra charge, to let people SEE the difference by installing ONLY a CPU, or a new CPU and new, faster RAM, let them run it for a few days, then changing the motherboard out with one designed for the new, higher powered CPU (and new, faster RAM, if any). If the customer doesn't see enough difference, they will put the old motherboard and RAM back in at no charge for anything but the new CPU (and any RAM they might want).

They tell me they have NEVER had someone want to go back to the old motherboard with only a CPU upgrade. Great sales method. They have a WONDERFUL reputation.