Vegas Preview Lag and my h.264 videos

[WhiteClaw48]

So, I'm new to all of this and may not ask the question like an expert would but here goes:

I'm currently using Sony Vegas 10 to edit my videos. A lot of my videos come as mkv h.264. I convert them to avi using alltoavi. Then I import them into Sony Vegas and start hacking away. When I have just one clip of the video on the timeline it runs smoothly...however, if I overlap another clip to do a fade in etc...it starts lagging horribly in my preview window.

I heard that Sony no likey h.264...is there something I can do to change this? Most of my videos come this way

[Pwolf]

well two things, when you convert it to avi, are you re-encoding them or does the program just move the h264 streams to an avi container? also, this is normal considering that the fade has to be rendered in order for you to see it. a simple fade usually doesn't slow down too much but depending on your computer specs, it's quite possible.

Best option is to convert your source to something lossless like Huffyuv, Lagarith, or UTVideo.

[WhiteClaw48]

Excellent information! What do you recommend I use to convert them to Lagarith? I've been using alltoavi to convert the mkv h.264 to avi but I think you're right and they're just putting them in a container.