As Perrone said, the type of media plays a big part but I would recommend that you use Preview (Auto). I can playback AVCHD at full 29.970 frame rate in Vegas Pro 9.0c on my anemic Centrino Duo T2500 2.0Ghz laptop using Preview (Auto). It stutters terrible using Preview (Full) or Preview (Half) and I wouldn't even think of using Good or Best.

~jr

To add to Perrone and John's comments, it sounds like you're using Pro 9.0 and this "switching" of preview rates is one of the new features that was added with this release.
It can be disabled by right-clicking in the Preview window and disabling the Adjust Size and Quality for Optimal Playback option.
Then you're free to set the Preview window playback options as desired.

Mike

Video clips are all AVI (uncompressed) files, 1280x720x32 or 1280x720x24.
On some spots there are two or three tracks of video clips plus some still images or text media.

Audio are wav files, 96,000 Hz, 24 bit, stereo, or 32,000 Hz, 16 bit, stereo.

Vegas Pro 9.0c

Will try Preview (auto) tonight and see what happens.

Add: Just saw Mike's suggestion. I will give that a try too, but wondering if that will still give me a decent fps.

> Video clips are all AVI (uncompressed) files, 1280x720x32 or 1280x720x24.

Two or three tracks of uncompressed HD requires a fairly beefy RAID 0 with more than 2 discs to maintain the throughput. Are you sure these are uncompressed HD? and if they are, are you sure that your hard drive is not the bottleneck? Uncompressed 720p would be about 280GB/hr (4.7GB/min).

~jr

I am sure about two tracks of video clips. I made them using the AVI (uncompressed) format. The same about the still images and text media, they are all 1280x720 resolution. Yes, although these clips are short, each of them exceeds 1 GB in general.

On some spots there is video clip in another track (that would make it a third track of video clips). That one I am not 100% sure. It could have been some other loss format. The resolution could also have been lower.

I didn't think about the hard drive. That could very well be the bottleneck. There is only one hard drive in this pc. SATA II, 7200 rpm, 1TB. Any suggestion on this area?

There is absolutely NO WAY you are going to get smooth playback of uncompressed HD with your setup. I'd suggest you use a codec more suitable to your hardware. Or that you purchase a RAID array, which is a good idea anyway.

> There is only one hard drive in this pc. SATA II, 7200 rpm, 1TB. Any suggestion on this area?

It has long been suggested that video editing workstations have a minimum of two hard drives (some recommend at least 3) and that you never place your media on the C: drive where you are fighting windows for the swap file and application files. So at a minimum I would recommend that you get another hard drive for your video projects.

As far as what kind, first determine if the hard drive is the problem. Is the hard drive light on solid when playing the files back or does it just blink on occasionally as the drive is read? There are also programs that will test the throughput of your hard drive to see if it's capable of sustaining 4.7GB.min. I use two 500GB drives in a 1TB RAID 0 for all of my HD editing but I don't edit uncompressed.

As far as what's needed to edit uncompressed HD, you can refer to Blackmagic Design's article on Disk Arrays for Uncompressed HD Video where they recommend a RAID 0 with at least 6 10K drives. Yikes! Some say that three 7200rpm drives striped together can deliver data rates up to 174MB/sec. The Blackmagic Intensity manual claims that the data rate of uncompressed 1080i footage is 120MB/sec. So you could get away with a RAID 0 of only 3 drivers.

I've never worked with uncompressed HD so perhaps someone here who has can give you more guidance. The only guidance that I can give is that I really don't think you want to work with uncompressed HD. Use a near-lossless intermediary codec like Cineform or a lossless codec like Huffyuv or Lagarith instead.

~jr

You're saying you have one hard drive - total - for your system? That's not going to cut it, especially for uncompressed 720p.

Take a look at the throughput chart here. According to this chart you'd need about 105 MB/s thoughput for one uncompressed stream at 720p. You've got two. <Edit - changed Mb/s to MB/s>

That 105MB/s is the minimum sustained throughput your hard drive needs for a single stream. Ideally you'd want much more and of course you'd want it to be available without interruption.

If your minimum throughput is greater than that then you ought to be able to play prerenders from disk even if the timeline itself won't play. And if you're previewing at half or quarter resolution playback would improve.

The RAM preview is also uncompressed, but in memory. Presumably if you set your RAM preview to 2GB and then actually render a RAM preview you'll get just as much into memory as a 2GB uncompressed file would contain. You need to watch out, though, that you're not starving other things for memory when you do this. That'll defeat the purpose.

Rob Mack

Great advices and info. I will check out the articles later.

The preveiw playback was actually quite smooth. There was only one spot where I could see a little stutter for a second or two. So that wasn't that bad. It was the video quality of playback that I was trying to improve. There were a only a few very brief moments the playback was Best(Full).
For the most part, it was Preview (Half). It never got worse than that though. Sounds like this is already the best the hardward setup can do.

I have a Western Digital Caviar Black SATA 3.2gb/7200rpm in an older pc. I think I can get it out to put in this one.

It probably won't make much difference in preview if I don't use RAID configuration. However, I have been hesitated to go RAID because of the risk of losing data if one drive fails. Do you think this is an over-concern?

Any thoughts on one of those 10,000 rpm drives? Will that help without the need to go RAID?

I've seen articles saying that a 10k to 15k RPM drive can perform as well as a 2-disk RAID array. They usually don't have a lot of capacity compared to 7200 RPM fare but if you're thinking about RAID this is a simpler option.

RAID can be a mixed bag. Yes, a striped RAID-0 array doubles your chances of failure but if you're doing backups that's not so horrible a risk. How often do your drives fail currently, after all?

One thing about RAID is that cheaper setups (on-motherboard controllers) add a processing load to your CPU. That can actually slow down a render a little. If you get a very good ($$) RAID controller card it'll do the processing itself. Usually you do this for RAID-5 support but any integrated RAID ought to be improved by using a good controller card instead.

You can blow a lot of money on very high end RAID. We've got three 16-disk Rorke units at work that probably cost a very pretty penny.

Rob

As you can see, I am not familiar with RAID. I even misspelled it earlier. I have never had a hard drive failure so far (knock on wood), but the double chance of that happen is something on my mind.

Sounds like I either have to live with what I have now or get a higher performance hard drive for OS and apps and two SATA drives for data (one for source, the other for output). I will also try the Lagarith.

Thanks all for your advices.

If you use RAID 10 for your drives a failure of one drive won't result in any data loss and they read as fast or faster than RAID 0 arrays because they can read from all 4 disks at the same time instead of just 2. RAID5 will also give you the ability to lose one drive without data loss but it's not as fast as RAID 0 or 10 for reads or writes.

Thanks,

RAID 10 looks attractive, too. For the same price of a 10,000rpm drive, I can probably get two 7200rpm ones. I already have one on the new pc, another one on an older pc, both 1TB. That will make 4 disks. I did a check and it seems there are enough room for 4 disks inside the case. I probably also need a RAID controller card?

But the first thing I need to decide is whether or not this pc in its current setup (i7 860, Win 7 Home, ATI HD 5850) is worthy of the upgrade. The other option is to save the money for a completely new hardware setup when the next generation of CPU comes along.

Thanks. I have learned a lot by asking this question.

I'm concerned that you might have missed the most important question here, do you really need to be working with uncompressed HD files?

Bob.

Yeah, you could be working with much smaller "visually lossless" files by purchasing Cineform's NEO Scene. It can be purchased for the cost of a single 1.5 TB drive.

http://www.cineform.com/neoscene/

Depending on your mother board = you may or may not have to get a RAID controller card. I use a 3ware 9650SE with a battery back up for 1 of my array's (RAID10) and the ICH10R on the board for the other array (RAID5) in my system. These 2 contain the same data with the exception of the OS which is on it's own partiion on the RAID10 Array. Most newer MBs have an ICH10R south bridge which will handle RAID10 for you.

If you have a couple 5.25inch bays unused - they can be converted to 3 drive bays using a back plane if you don't have enough HDD bays already in the case. I converted 4 unused 5.25 bays to 6 HDD bays which combined with the 3 bays already in the case gives me 9 to work with - a spare is used for a single disk I do periodic back ups too and remove the rest of the time, the RAID5 is a 4 disk array (you can have more than 3 disks in a RAID5, minimum is 3).

"I have tried to increase the Dynamic RAM Preview Max (MB) to 1,000 and 2,000 where the total available is 7,163 MB. It didn't seem to help."

Preview ram does not work that way. It reserves a certain amount of ram for previewing highlighted areas

If you need to preview a complex part of the time line at full frame rate then highlight the area in question then press shiftB. This loads that highlighted part into the reserved chunk of memory for full playback via memory.

It has nothing to do with preview performance in the way that you are thinking. In fact if you don't use "shiftB" then all of that ram you have reserve is totally wasted.

"In fact if you don't use "shiftB" then all of that ram you have reserve is totally wasted."

Worse, having too much RAM allocated to preview can have a quite negative impact on preview performance.

Bob.

As far as I'm concerned, I just treat Cineform codec video like it was uncompressed. I simply can't see any difference, even after multiple generations. There is a bit of color shift if you go past 10 or more generations but that is mainly due to multiple YUV to RGB color conversions rather than the codec, and you can simply check the "use RGB" tab if you are worried about it.

Cineform also smart renders so that most rerenders are just file copies rather than rerenders.

With Cineform I can use an average off the shelf USB 2 hard drive for most projects which is really nice as well.

Hi all, Great advices and info. To get to the bottom of this and hopefully help others who may also want to improve preview quality, I did the following tests. Please review the results and let me know if my interpretations are correct.

To make things simple, I choose a 9-second AVI (uncompressed) 1280x720 clip as the test material. First, I made another clip of same using AVI compressed with Lagarith. Second, I rendered the uncompressed AVI clip to Sony MXF format. Thus, I had 3 clips.

I unchecked the 'Adjust Size and Quality for Optimal Playback' option in preveiw and set the preview quality to 'Best(Full)'. Each of the clip was place on one track, nothing above or under it ( in other words, one layer). Here were the results:

Uncompressed AVI: 29.97 fps (full frame rate) all the way. No stutter. Hard drive light: constant red indicating busy.

Lagarith AVI: Fluctuated between 18 and 29.97 fps, mostly 21-26 fps. Hard drive light: Blinking in a relaxed pace, indicating less busy.

MXF: 29.97 fps all the way. No stutter. Hard drive light: not on most of the time, hardly blink - not busy at all.

Adding up to two layers of MXF clips on top of each of the above with Chromakey effect had minimal effects on their respective playback framerate.

Conclusion: My pc can playback one layer of uncompressed AVI plus at least two layers of MXF clips, at full framerate.

Question: Why couldn't the AVI clip compressed with Lagarith play back at full framerate despite its much smaller size and less demand on hard drive? The need to decode slowed down the pc? It seemed something other than hard drive throughput might play a big role in preview performance.

I then went on to test if my pc could playback two layers of uncompressed AVI. The answer was no. The frame rate dropped to somewhere between 11 and 24.

I repeated the above test using a 5-second clip as test material. The results were similar.

Continued from the post immediately above...

One observation: The 'Adjust Size and Quality for Optimal Playback' option must have used a very conservative algorithm to determine playback quality. When I used that option the playback quality was either Preview(Full) or Preview (Half), when in fact my pc can play back at full frame rate at Best(Full). The worst video quality I got was using the Preview (Auto) option, however. That one must have used an even more conservative algorithm.

So here is a strategy based on your inputs and the tests. Let me know if it makes sense.

I will use one layer of uncompressed AVI, while converting the other two layers into MXF format, or use CineForm Neo Scene as an upgrade.

The only concern that I have with using intermediates is that I am new to editing. While experienced editors may have a good idea what they will get without having to actually see, I totally rely on what's presented in front of me to determine if the color correction or any other effects are working or not. So if the intermediates have color shifts then it could be a problem.

If I absolutely need to use two layers of uncompressed AVI, then I will: 1) use the Dynamic RAM preview by highlighting and shiftB, or 2) simply do a pre-render into uncompressed AVI (the file will be huge though), or 3) Go RAID 10.

Now on RAID 10, I am not sure it alone will work since hard drive throughput may not be the only problem. There can be something else in my pc setup that's the bottleneck.

> The only concern that I have with using intermediates is that I am new to editing

If you use Cineform you have nothing to worry about. What you see is what you get. MXF is also a great option for you from the looks of your performance tests.

> If I absolutely need to use two layers of uncompressed AVI...

Just curious... How did you acquire these uncompressed HD files? I know this has been said before but it bears repeating. You gain nothing by using uncompressed video since you probably didn't capture uncompressed HD via SDI because you would have needed a serious RAID and SDI card just to capture it.

Forget about uncompressed, render everything to MXF or Cineform and just have fun editing.

~jr