[Dan Sakols] “Im shooting at 30fps. for encodes I force an I frame every 24 frames as a rule of thumb. does that sound about right?”
This is entirely up to you and the resulting file sizes you want. More I frames typically means a larger overall file size when finished. If you have a lot of fast motion (cars, sports, etc.) then more frequent keyframes usually helps maintain quality. However, it’s just a guy taking against a static background then you can use less. Additionally, you can use less keyframes if you use 2-pass or multi-pass encoding as the software then analyzes the footage and decides where best to place the keyframes.
For most of what I do, I typically will place a keyframe at the same rate as the frame rate. So if I’m doing 30fps I’ll do a keyframe every 30 frames. If I’m doing 24fps then a keyframe every 24 frames, etc. So I usually end up with 1 keyframe per second. And I almost always use 2-pass encoding unless it’s a time crunch or I don’t care as much about the output (i.e. it’s just a rough preview).
Ryan Holmes
http://www.ryanholmes.me
vimeo.com/ryanholmes