https://wiki.archlinux.org/index.php/FFmpeg

• 1 Package installation
• 2 Encoding examples
  • 2.1 Screen cast to .webm
  • 2.2 Recording webcam
  • 2.3 VOB to any container
  • 2.4 x264 lossless
  • 2.5 Single-pass MPEG-2 (near lossless)
  • 2.6 x264: constant rate factor
  • 2.7 YouTube
  • 2.8 Two-pass x264 (very high-quality)
  • 2.9 Two-pass MPEG-4 (very high-quality)
    • 2.9.1 Determining bitrates with fixed output file sizes
  • 2.10 Adding subtitles
    • 2.10.1 Softsubs to hardsubs
  • 2.11 Volume gain
  • 2.12 Extracting audio
  • 2.13 Stripping audio
• 3 Preset files
  • 3.1 Using preset files
    • 3.1.1 libavcodec-vhq.ffpreset
      • 3.1.1.1 Two-pass MPEG-4 (very high quality)
• 4 Package removal

YouTube Downloader Site
http://www.youtubedownloadersite.com/help.html
Iphone Video (MPEG-4 MP4) 

ffmpeg -i %1 -vcodec mpeg4 -s 480×320 -r 29 -b 900k -ar 44100 -ab 96k -ac 2 %1.mp4

ffmpeg -i %1 -vcodec mpeg4 -qscale 15 -s 480×320 -r 29 -b 900k -ar 44100 -ab 96k -ac 2 %1.mp4

ffmpeg -i %1 -vcodec mpeg4 -qscale 7 -s 480×320 -r 29 -b 900k -ar 44100 -ab 128k -ac 2 %1.mp4

ffmpeg -i %1 -vcodec mpeg4 -qscale 1 -s 640×480 -r 29 -b 1500k -ar 44100 -ab 128k -ac 2 %1.mp4