>Find data:
ffmpeg -i video.mp4
>example result, excluding the ffmpeg data:
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.41.100
  Duration: 01:22:02.50, start: 0.000000, bitrate: 3667 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 3500 kb/s, 30 fps, 30 tbr, 90k tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 160 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
>among other things, in the 'Stream #0:0' line, you can find the fps of the file

>Trim stuff:
>either
ffmpeg -ss 00:01:00.5 -i input.mp4 -to 00:02:01.1 -c copy output.mp4
>or, if you want to specify the duration in seconds
ffmpeg -ss 00:01:00.5 -t 60.6 -i input.mp4 -async 1 output.mp4
>the last one depends on fps
>say, you have 30 fps, so any ms would have to be a multiple of 1/30 or ~0.033

>Youtube:
youtube-dl -F [link]
>this should give you the list of available video and/or audio formats
>and then you do
youtube-dl -f [number]+[number] [link]
>first number has to be video, tho
>second number is optional if the first one doesn't say video only