>>108465
Okay, I'll write a brief guide on how to set up and use ffmpeg on Windows for
>>108452 .
Download the ffmpeg binaries (ffmpeg.exe, ffplay.exe, and ffprobe.exe) and put them in a folder where you'll never move them. I put mine in a folder named "ffmpeg" on the root of my C: drive.
Click on the start button and type "env" and select "Edit the system environment variables".
In the window that opens, click "Environment Variables".
Select "PATH" and click "Edit".
Click "New".
Paste the complete path to the folder containing your ffmpeg binaries. In my case, it's "C:\\ffmpeg".
Click "Ok" on all three windows.
You can now run ffmpeg from anywhere on your system.
To quickly open a powershell window in any folder, just hold shift and right click in an empty space in the windows and select "Open PowerShell window here" (note that this won't work if you are viewing a search result of a folder).
Opening a PowerShell window within a folder just means that the shell is automatically navigated to that folder when opened, meaning that you don't have to copy and paste full paths to files, just local paths, which are usually just the file name itself.
Actually using ffmpeg is not that hard. You might have to refer to the documentation occasionally, but the basics are simple.
-i is used to define an input. You can have as many input files as you need.
-map is used to map a file or parts of it to particular output streams. -map 0:v for example will map the first input file to the video stream of the output, -map 1:a will map the second file to the audio stream of the output. (computers start counting at 0, please remember this).
-c is used to describe what codec should be used. -c:v copy tells ffmpeg to simply copy the video from the input to the output, skipping the step of re-encoding. If the type of file you want to output doesn't support the codec of the input file, you'll get an error if you try to copy it. This is why the command I provided doesn't use -c:a copy, because webms can't have an mp3 audio stream, and most soundposts use mp3 files.
The very last argument in an ffmpeg command should be the output file itself. You can name this whatever you want.
You don't always need all of these arguments either, in most cases you can get away with just typing
ffmpeg -i video .webm -i audio .mp3 -c:v copy out.webm and it will just work. I only included the map arguments to account for cases where a video file is used as an audio source.
If you need more info, go here. It will have the answer to 90% of all questions you could ask about it.
https://ffmpeg.org/ffmpeg.html
Here's one tip you might not find in the documentation.
If you're encoding an mp4 file, make sure to include
-pix_fmt yuv420p so that your file will work on all operating systems/web browsers. Ffmpeg defaults to yuv444p.