I have used the Smart Proxy feature of Vegas. The proxies it generates are 720p24 XDCAM EX 35Mbps VBR files. No frame rate resampling is done. This is mpeg-2 video and it decodes very fast.

The only thing I used it on were GoPro 1080p60 AVC files, which were also about 30Mbps. Since the 60p was encoded as 24p, without resampling, at similar bitrates, my proxies were about 2.5 times bigger than the sources, but decoded with *much* better performance. Perfect performance really.

The proxy is used when you are in Draft or Preview playback quality. Good and Better use the original source file. This all just happens automatically. Rendering is always at a minimum of Good, so the originals are used for that.

These proxies are encoded like 720p EX 35 Mbit but used in the Vegas timeline their fps informations are handled kind of single frames (no frame rate branding first) before Vegas conforms their framerate information to the framerate of the original files. So if your footage is 60p, the fps information of your timeline proxies will be processed bit similar to an image sequence with 60 fps information. In this certain case the fps information will not be read by a proxy file header but by the orginal file.
Analyzing the .sfvp0 files will give confusing results. Them are no good to be used solely in any way. They strongly need information from their root files.

and so as Marco is suggesting the efficiency of the built-in proxy has some less flexibility than may be desired. Prefer the control in Gearshift and Vegasaur.

I tried Vegas own proxy feature but switched back to Vegasaur because you get so much more control over the proxies format with Vegasaur.

@ oldsmoke - what flavour proxy('s) do you prefer?

@usher

I use proxies only for my 4K workflow and I use Sony MXF 1920x1080 29.97p. This makes for a very smooth editing experience. I use Vegasaur to create the proxies but I don't use the Vegas compatible files nad rather go for "Replace Media" at the end of the proxy creation process.