AVI uncompressed, sound stutters, behaving strange

ingvarai wrote on 5/24/2009, 5:10 AM
Something just happened, strange..
I have captured fom VHS using a Canopus 300 device. I am almost sure that the media I stored is AVI uncompressed media. G-Spot reports "dvsd codec", I do not know what this is though.

Putting a 10 seconds clip on the Vegas time line, I set the project properties to match the media, 720x576 50i lower field first PAL.
Pixel format 8 bit.

When rendering to uncompressed AVI, the file gets ten times bigger, it was 50 Mb and becomes almost 500 Mb. When playing it back in Windows media player, the the sound stutters all the time. I have never seen anything like this. The new 500 Mb AVI uses _RGB codec according to G-Spot.

I also would like to mention that rendering takes ages, I do not remmember that rendering this low res AVI source to a low res AVI dest file would be slow at all, when rendering uncompressed.

I have also tried to render 1920x1080 AVCHD to uncompressed AVI, sound stutter here too, playback is jerky.
Rendering to Lagarith or Canopus HQ codecs is fine. Just AVI uncompressed gives this weird trouble. I have used Vegas 18 months now and never seen (heard) anything like this.
ingvarai

Comments

srode wrote on 5/24/2009, 5:23 AM
I would guess you are seeing the effect of drive speed limiting the feed of audio/video to your computer - big media files and slow drives don't work smoothly. A RAID 0 Array might speed things up.

Either that or your player is not keeping up due to the CPU/MB.
farss wrote on 5/24/2009, 5:36 AM
"I have captured fom VHS using a Canopus 300 device. I am almost sure that the media I stored is AVI uncompressed media"

Nope, just plain old DV at 25Mbps, that's what G-Spot is telling you as well.

Bob.
TheHappyFriar wrote on 5/24/2009, 5:49 AM
rending to uncompressed AVI in HD will make files in the GB size pretty easy too (I'd suggest QT PNG, it's uncompressed, smaller &, for some reason, looks better).


Playing back uncompressed takes a lot of hourse power in the CPU+drive. But it also normally renders faster vs DV to another codec, IF the drive can keep up. When you render from DV to something else it needs to uncompress, render & recompress. uncompressed to something else eliminates a step.
ingvarai wrote on 5/24/2009, 6:32 AM
would guess you are seeing the effect of drive speed limiting the feed of audio/video to your computer

[Red face, blushing, want to hide]
You are right! I very well know this, because even if I store footages on USB drives, I always do my work on very fast SATA drives. This time my head was confused, so I rendered to this USB drive.. Correcting this, all is fine, it renders faster than real time and no stutter at all. Thanks alot, and please don't snigger behind my back!

ingvarai
farss wrote on 5/24/2009, 6:49 AM
Uncompressed places the least demand on the CPU as only minimal decoding is required. Given that Ingvarai is rendering to HD, uncompressed is going to give a HUGE file size and for nothing given that he's starting mostly from VHS captured to DV. A far more rational codec would be the XDCAM 422 codec. At 50Mbps it gives a workable file size and seems easy enough on the CPU from my tests on basic quad.

Certainly in SD there's perhaps a small speed advantage from uncompressed however in HD drive and disk i/o bandwidth is going to slow things down a lot unless you've got serious hardware.

Bob.
ingvarai wrote on 5/24/2009, 6:51 AM
disk i/o bandwidth is going to slow things down a lot unless you've got serious hardware.

I never thought about this. OTOH, I do have fast disks, 10 000 rpm.
farss wrote on 5/24/2009, 7:09 AM
Unless you're running SAS drives and several of them, good luck.
Uncompressed HD is over 1Gbps, a few 15K SAS drives in RAID might be in order.
Also 70% of the data is pretty much wasted. If you've upscaled DV to HD it's really 2:0.5:0.5 and you're storing it at 4:4:4:4, don't forget the alpha channel!

Bob.
ingvarai wrote on 5/24/2009, 9:19 AM
I am running several WD Raptor 10k rpm in RAID 0, striping. I have no idea to what extent disk access is the bottleneck. I thought it was compression / decompression that slows things down.
15 k is not planned here so far, maybe when I get a mobo with dual i7 Nehalem CPUs..

ingvarai