FFmpeg Installation, Usage, Options, and Commands

FFmpeg is a powerful tool that can execute video/audio conversion, compression, extraction, concatenation, etc. via command line. This article aims to “avoid confusion even for first-timers” by summarizing basic command structure and frequently used options in tables with usage examples. Also includes practical recipes ready for copy-paste.

Installation

• macOS (Easy to use Homebrew):

1. Install Homebrew (only if you haven’t)

2. Install ffmpeg (execute following command from terminal) brew install ffmpeg

3. Check version ffmpeg -version

• Windows:

  • Official distribution or choco install ffmpeg (Chocolatey), etc.

  • Check with ffmpeg -version after installation.

• Linux:

  • Use distribution’s package manager (e.g., sudo apt install ffmpeg).

Basic Command Structure (Most Important)

FFmpeg basic form is below. Conceptually it’s flow of “input → processing → output”.

ffmpeg [global options] [input options] -i [input file] [output options] [output file]

Role of Each Part

Points (Order is Important)

• For most options, “which output it affects” is determined by position. In principle, options written “before” output filename are applied to that output.

• Specify input with -i, then line up codec, bitrate, filters (-vf/-af), etc., and write output filename at end.

• Multiple outputs possible in single command (place options right before each output).

Command Example

ffmpeg -y -i input.mp4 -c:v libx264 -crf 23 -c:a aac -b:a 128k -vf "scale=1280:720" output.mp4

Command Example Breakdown Image

ffmpeg \
  [global] \            # -y (overwrite output file without confirmation)
  -i input.mp4         # Input (container: MP4, contains video/audio streams) \
  -c:v libx264 -crf 23    # Video codec settings (libx264) and quality (CRF) \
  -c:a aac -b:a 128k      # Audio codec (AAC) and audio bitrate \
  -vf scale=1280:720      # Video filter (e.g., resize) \
  output.mp4              # Output

Terminology Memo (For Beginners)

Frequently Used Options Quick Reference (With Usage Examples)

Note: For H.264/H.265 quality priority, -crf+-preset is basic. Only consider -b:v (2pass recommended) when there’s clear target size.

Note 2: -r has different meaning on input side and output side. -r placed before input is specification “consider input frame rate as this”, unnecessary for normal MP4 etc. Output side -r specifies “output target fps”.

Ready-to-Use Commands (Copy-Paste OK)

1) MOV→MP4, CRF 25 specification

ffmpeg -i input.mov -crf 25 output1.mp4

2) Video trimming (30 seconds from 1-minute point)

ffmpeg -i input.mp4 -ss 00:01:00 -t 30 -c:v libx264 -crf 22 -c:a aac -b:a 128k output_clip.mp4

Memo: Placing -ss “after” input improves frame accuracy (speed slightly decreases).

3) Fast rough trimming (keyframe basis)

ffmpeg -ss 60 -i input.mp4 -t 30 -c copy output_fast.mp4

Memo: Place -ss “before” input, no re-encoding with -c copy. Cut point becomes approximate.

4) Mute audio (video re-encoded)

ffmpeg -i input.mp4 -an -c:v libx264 -crf 23 output_noaudio.mp4

5) Extract only audio (WAV or MP3)

# WAV (uncompressed)
ffmpeg -i input.mp4 -vn -c:a pcm_s16le -ar 48000 -ac 2 output.wav

# MP3 (compressed)
ffmpeg -i input.mp4 -vn -c:a libmp3lame -b:a 192k output.mp3

6) Resize to 1280x720 resolution

ffmpeg -i input.mp4 -vf scale=1280:720 -c:v libx264 -crf 22 -c:a aac -b:a 128k output_720p.mp4

7) Export with target bitrate (2Mbps)

ffmpeg -i input.mp4 -c:v libx264 -b:v 2M -c:a aac -b:a 128k output_2m.mp4

Example: -b:v 2M. “Video quality is not guaranteed. Try with your desired bitrate.”

8) Quality priority (CRF basis)

ffmpeg -i input.mp4 -c:v libx264 -crf 20 -preset medium -c:a aac -b:a 160k output_crf20.mp4

9) Concatenate multiple videos (assuming same codec/resolution/frame rate)

# 1) Create list file (e.g., files.txt)
# file 'part1.mp4'
# file 'part2.mp4'
# file 'part3.mp4'

# 2) Concatenate with concat demultiplexer
ffmpeg -f concat -safe 0 -i files.txt -c copy merged.mp4

10) Burn in subtitles (SRT)

ffmpeg -i input.mp4 -vf subtitles=subs.srt -c:v libx264 -crf 22 -c:a copy output_subbed.mp4

11) Rotate 90 degrees (clockwise)

ffmpeg -i input.mp4 -vf "transpose=1" -c:a copy output_rotated.mp4

12) Convert frame rate to 30fps

ffmpeg -i input.mp4 -r 30 -c:v libx264 -crf 22 -c:a aac -b:a 128k output_30fps.mp4

Specifying -r 30 is common. However, “frames are not interpolated, they are thinned/duplicated”

Common Questions/Troubleshooting

Reference Links

• Official site: https://ffmpeg.org/

• CRF explanation (English): https://slhck.info/video/2017/02/24/crf-guide.html

Above summarizes FFmpeg’s “basic template”, “standard options”, and “ready-to-use recipes”. First try running samples with copy-paste, then adjust parameters as needed.