The number one complaint from users of Sony Vegas Pro or Sony Vegas Movie Studio HD Platinum, is about the playback lag in the Preview Window which makes the video stutter.
In this tutorial I will explain the main reasons why this occurs and also offer some solutions. This article is actually one of four that I have uploaded in an attempt to offer the widest possible solutions to this common problem. The next three tutorials in this series are listed at the bottom of this article.
Technology changes that exacerbated the problem
This problem became a big epidemic when people started to upgrade from using Standard Definition Cameras to AVCHD Video Cameras, but were still using their old computer running a Duo Core CPU. Full 1080p HD Video is up to six times larger in file size compared to Standard Definition video that DVDs use. So that means that your CPU "Central Processing Unit - the brain of your computer", needs to do six times the work to play it back when editing with Vegas. On an older computer, 1080p HD Video will virtually freeze up the whole machine.
The other big problem with HD Video Cameras is the Video Codec they use to save your videos. The vast majority of cameras use AVCHD H.264 video codec which is highly compressed. What that means is that Vegas has to do a lot more work to "decode" the video as it is playing it back in real time - this definitely adds to the lag problem. If you were to convert your AVCHD Video into a non-compressed .avi codec before importing it into Vegas, you would notice a big improvement in playback quality, however this method requires that you have tonnes of Hard Drive space. Uncompressed video is MASSIVE - AVCHD video can go from being a couple of hundred Megabytes to Gigabyte file size - it's a real catch 22 situation.
So the number one thing you can do to improve playback quality in Vegas, is to make sure your computer has at least a modern 4 X Core CPU running at a decent GHz speed. If you're on an old clunker then it is time to buy a new computer if you really are serious about editing HD Video.
All the other components in your computer also have an important influence on how well videos playback in Sony Vegas. A decent GPU "Graphics Processing Unit", fast and clean Hard Drives and plenty or RAM "Memory" also need to be looked at. Increasingly Sony Vegas and other video editing programs, are now utilising the power of your GPU to speed up rendering times and increase the playback quality in the preview window. I have plenty of other articles on this website that talk about how to optimise your computer for video editing, so I won't go any further onto this tangent.
Sony Vegas Preview Window Settings
The easiest way to help reduce lag in the Preview Window is to have a close look at your Sony Vegas settings. The Preview Window has four quality and size setting combinations that have a big influence on the playback quality. Setting everything to the highest settings is a recipe for failure, so try reducing the quality settings until the lag disppears. In the video below I will show you exactly what to do.
GPU Acceleration in Sony Vegas Pro 11
If you are using Sony Vegas Pro 11 then please make sure that you have your GPU selected from the Video Preference Settings. Having this turned ON will definitely improve the playback quality. Once again, I show how to do this in the video below.
Proxy Video Editing
Proxy Video Editing is a process where you create lower quality Standard Definition copies of your original HD videos and edit/create your project in Vegas using these lower quality versions. Then once you have finished all your editing you then replace the SD Versions back with the original HD Video files and render your project with them. Proxy Video Editing should totally eliminate any lag in the Preview Window.