How do people get their speedruns timed perfectly to the ms? The only tool I have is LiveSplit, which requires me to push a button at the beginning and the ending. I don't trust my own reaction time to be frame perfect.

Some games have autosplitters. They split from beggining to end by themselves.

There are also programmes which allows you to look at a video's each frame.

Some games have autosplitters that will do the work for you, and other games are timed by IGT in which you just add up the level times you get throughout the run. Simple mathematics.

For other games that are timed RTA, the majority of them are not optimised enough to warrant timing to the frame and are simply timed to the second. These ones are easy to do just by looking at the run, even via timestamps.

For the games that really do require framecounting, you'll often end up doing it the 'hard way'; download the video of the run, stick it in a video editor and do it yourself. It's not too tricky to isolate the frame the run starts on and the frame where the run ends, then count the frames between those two points. You'd then convert it into a timing format, assuming the framerate of the video matches the framerate of the game.

DL video, frame count, convert frames to time.

i personally use this http://www.watchframebyframe.com/ to review other runner run and i use avidemux to edit my run and retime them before putting them on youtube

There are a few games with autosplitters, and then some that have an IGT system (although a lot of these games switched to RTA timing, too) There are also other runs timed RTA that you might as well not framecount (for example, if the run's over 25-30 minutes, there's a pretty good chance that they won't even display the millisecond timer here on Speedrun.com). But, if it's a shorter, more optimized run without an IGT system, you'll have to framecount. There are multiple ways to do this. There are freeware programs, like Avidemux, that show the current frame you're at (which makes it way easier to determine how long the run really was), and even VLC has a way of doing this (although VLC does not display this option by default, you can enable it via a menu option: View > Advanced Controls, and then there should be another row, the last button is a frame-by-frame button)

When I tried http://www.watchframebyframe.com/ I had a problems:

1. How can I know video fps?

2. Other Moderators have thousandths seconds, and I only hundredths.

3. Every time I meassuring time, I get different time

4. If it's possible, can someone tell me formule of counting time by frames.

Whatever website that is, is severely outdated. Most people use https://retime.mcbe.wtf/ , https://somewes.com/frame-count/ , or https://noobjsperson.github.io/speedrun-timer/ . Some people still use https://github.com/Slush0Puppy/retime/releases but this one as accuracy issues and theres really no need to download an application. https://github.com/zugebot/Jerrins-Retiming-Tool is useful if your game has a complex form of retiming, but usually communities make autosplitters for better accuracy, since youtube compression can make retiming inaccurate.

Avidemux can also be used, but its best used with raw footage from local recording, torrents, or mega/dropbox submissions. Once again, youtube compresses footage.

To get framerate, right-click on a yt video and click "stats for nerds". A bunch of stats will appear, with one of them being the frame rate. Most common framerates are 60, 30, and 25, but you will occasionally see 57, 27, 29, 19, and 11. For leaderboard accuracy sake, its best to round to a number divisable by 6.