Comments

winrockpost wrote on 4/21/2006, 8:55 AM
thats about right
Chienworks wrote on 4/21/2006, 8:56 AM
It seems like with that system it should be faster than that. But, uncompressed frames have a lot more data to sift through so Vegas has to do more reading and processing to display each frame.
Marco. wrote on 4/21/2006, 9:07 AM
Because of the extremely high data rates of uncompressed video you'd need very fast hard-drive systems and busses.

Marco
rmack350 wrote on 4/21/2006, 9:32 AM
If I recall, Uncompressed with Alpha actually played back a little faster than without. It's been a while and I don't remember why that should be. Seems counterintuitive since the file is a little bigger and requires more disk throughput. In any case I never got either to play at full framerate off a single disk.

<time passes...> Not only is it counterintuitive, It's also wrong. I just made to renders and, as expected, Uncompressed with Alpha has a slower playback rate that Uncompressed without Alpha. Looking at the details in the project media window I see that the file without alpha has an average total data rate of 31.67 MBytes/sec. The same thing with an alpha channel has a data rate of 42.15 MBytes. I was playing them off a firewire drive which is not the fastest source to begin with.

In contrast, the same thing rendered as Sony YUV says it's data rate is 21.174 MBytes. A DV25 render of the same thing reports back as 3.8 MBytes/sec.

If you need to save video with an alpha channel (say your are going to encode as Flash VP6 with alpha) then Uncompressed is the way to go. The quicktime animation codec is a good second choice.

You could probably get full framerate with uncompressed off a 10k rpm Raptor or a striped array of 2 disks or more.

Rob Mack
jkrepner wrote on 4/21/2006, 11:28 AM
Okay, so it's more of a disk throughput issue than computing power. Got it.

I guess that makes sense. I used to cut uncompressed video at faster playback rates on the VT2 on a P3, but I also had 4 SCSI drives stripped.

Would a hardware stripped 2 or 3 SATA drive array get to 29.97? The 10K drives are only 73GB if memory serves me correctly.

Thanks.
winrockpost wrote on 4/21/2006, 11:41 AM
i doubt it, remember even though ithe box may say different, Vegas is mainly a DV and HDV editor. IMO .There are those that have Vegas set up to edit uncompressed, but i think it will take more than a couple striped sata drives.
jkrepner wrote on 4/21/2006, 12:01 PM
I hope "they" change that soon. Not all new cameras are DV or HDV and not all files are DV25.

Thanks.
winrockpost wrote on 4/21/2006, 12:32 PM
Dont get me wrong, Vegas can do it now,, just not by itself, its software, you have to have some ad ons ,such as blackmagic card,probably
SCSI drives and some speed,, someone that knows about it thats doin it will pipe in and tell you how.
Chienworks wrote on 4/21/2006, 12:57 PM
"I hope "they" change that soon. Not all new cameras are DV or HDV and not all files are DV25."

Vegas can do all that now. Vegas doesn't have the problem and nothing has to be done to it to handle uncompressed and high-end video formats. Its the hardware that is too slow to handle all the data that fast.
rmack350 wrote on 4/21/2006, 2:18 PM
Douglas is doing it and I think others are as well.

You have a tradeoff when you use uncompressed. There's a lot less cpu overhead because you aren't decompressing anything, but you need a lot more disk output.

When I tried out a single SD stream of 32bit uncompressed this morning I was getting a little over 20 fps from a firewire drive. 27 fps for the 24bit version, still from the firewire drive. I'd be willing to bet that the 10k Raptor drives (up to something like 160 GB now) could play a single stream easily.

When you're editing you often need more than a single stream though. A crossfade will need to get both pieces of media and I suspect that the more discs in array, the easier that will be. In a four disk array each head ought to have more time to get to the spot on the platter that has the data. I'm just guessing at that but it makes some sense to me.

People don't usually edit a project that is entirely uncompressed, but as you start to work with 10 bit media at HD resolutions you're going to need more thoughput even for compressed media.

Rob Mack
TheHappyFriar wrote on 4/22/2006, 6:14 AM
ok, could you say HOW you're previewing this stuff? If I preview uncompressed 24-bit TGA's at DV resolution in the preview window at any quality (~34 seconds worth @ 30fps progressive), I have no problem playing them back at 30fps in the preview window (again, any size or setting. Full, auto, etc). Uncompressed AVI WIHT ALPHA the same results (I just used the uncompressed template defaults).

That was off a Western Digital 120gb 7200rpm ATA 133 drive with eigther 2 or 8mb cache (not sure, can't find out how much ATM but I got it on sale). It's ~70% empty (just use it for games & misc video stuff, like this test).

Now, on my C drive, I got the EXACT same results as you: 15fps max.

I don't have great system specs eigther... AMD 64 3000 & 1gb generic DDR 400 with on sale/clearence HD's. :) The only thing "wierd" about my system is that I have a 3gb swap on the non-C drive.
RBartlett wrote on 4/22/2006, 7:29 AM
YUY2, RGB24 and RGB32 do seem to have both a processing and disk I/O "tax" when run through Vegas. For example NewTek had multiple realtime uncompressed and (mainconcept-DV or PICVideo aided) alternatives codecs running with full preview (on windowed VGA viewports) and the external interfaces even on lowly PentiumIV 1.4GHz systems quite a few years ago. Mostly because they got to the point where they were rewriting directshow elements and they also scratched out hand written assembly code deep down at the level that most developers would instead buy-in or download a general purpose DLL/SDK/API code for.

However I've heard folks claiming to get full field/frame representation (with DV-preview too) of uncompressed standard def (D1) sources with Vegas. Also with digital-intermediate variations of HD res material (whether or not from HDV sources).

Now I've found that DV and MJPEG works OK through Vegas on the system I bought back in ~2003. I can scale, position and put simple filters on the material and it plays OK. Much else and I am left in draft mode window-preview, and I can see my material performing sluggishly VGA-preview or DV-preview. I expect to need a new PC, but I am mindful that other editors can do some of the basic Vegas functions faster.

A $40 parallel IDE drive can sustain >40MBytes/sec across the entire surface, unlike SCSI there will be a CPU/DMA tax unless you use specialist drive controller. Ideally you throw a dual- Opteron, dual-core Athlon64 or dual-Opteron-dual-core at this and buy yourself some more I/O and NLE headroom. These are the $1000->$2500 type workstation systems.

So given that a $40 drive is good enough for almost two uncompressed standard def streams (without alpha), and that WMP can play them in YUY2 and RGB format with only the compromise regarding the interlaced fields being drawn together by way of Windows not being all that video centric. It follows that there is a technical wall that is only overcome when you both own Vegas and a half decent system with no weak link in the chain between the file on the disk and your scrubbing/playing media from Vegas. SonyYUV ought to be another exception to the latency issue, but I've not had the experience to say that this is so.

What is important though is that when we quote 15fps or 30fps preview that we state whether fields are of any significance in this project (ie interlaced sources) or if we have a whole stack of filters and effects on the timeline. Vegas is pure software, NewTek VT is pure software, WMP is, ShowShifter is, .....

Onboard (southbridge) SATA controllers are becoming superb achievers and with new memory bandwidths (DDR2, DDR667, XDRAM with low latency versions that keep following the initial launches etc) all together with unshared PCI-express bandwidth "lanes" and superb CPUs - this situation ought only to get better even if Sony stand completely still on us.

I just wanted to point out that system performance (not having AV/personal-firewalls running, suitably sized and placed virtual-memory swap files, optimisations to what you else you have in the process table, secondary storage, adequate amounts of memory) are really just as important as disk I/O performance and access times.

Single stream HD uncompressed is what you need to spend ~$3000-$8000 on the base system before you buy what hard disk capacities you need. IMHO. I am not talking Vegas here, as AFAIK, DigitalIntermediate is the only way to go with this NLE right now.