the_information_nexus/tech_docs/linux/ffmpeg_guide.md

Creating a basic guide to ffmpeg involves covering some of the most common and useful tasks you can perform with this versatile tool. ffmpeg is a powerful command-line tool that allows for video, audio, and other multimedia file processing. Here's a beginner-friendly guide to get you started:

Introduction to FFmpeg

ffmpeg is a comprehensive multimedia processing tool that supports a wide range of formats and tasks, including video and audio conversion, processing, streaming, and more. It's used by professionals and hobbyists alike for its flexibility and powerful capabilities.

Installing FFmpeg

Before diving into ffmpeg commands, ensure you have ffmpeg installed on your system.

• On Ubuntu/Debian:

  sudo apt update
  sudo apt install ffmpeg
  

• On Fedora:

  sudo dnf install ffmpeg
  

• On macOS (using Homebrew):

  brew install ffmpeg
  

Basic FFmpeg Commands

1. Converting Video Formats

One of the most common tasks is converting videos from one format to another. To convert a video file, use the following command structure:

ffmpeg -i input.mp4 output.avi

Replace input.mp4 with your source file and output.avi with the desired output filename and format.

2. Extracting Audio from Video

You can extract audio tracks from a video file into a separate audio file using:

ffmpeg -i input.mp4 -vn output.mp3

This command takes the audio from input.mp4 and outputs it to output.mp3, without the video part (-vn stands for "video no").

3. Trimming Video Files

To trim a video file without re-encoding, specify the start time (-ss) and the duration (-t) of the clip you want to extract:

ffmpeg -ss 00:00:10 -t 00:00:30 -i input.mp4 -c copy output.mp4

This command extracts a 30-second clip starting at the 10-second mark from input.mp4 to output.mp4, copying the streams directly without re-encoding.

4. Combining Video and Audio

To combine a video file with an audio track, use:

ffmpeg -i video.mp4 -i audio.mp3 -c:v copy -c:a aac output.mp4

This merges video.mp4 and audio.mp3 into output.mp4, copying the video codec and transcoding the audio to AAC.

5. Reducing Video File Size

To reduce the size of a video file, you can change the bitrate or use a different codec:

ffmpeg -i input.mp4 -b:v 1000k -c:a copy output.mp4

This command re-encodes the video to have a lower bitrate (1000k bits per second), potentially reducing the file size.

Tips for Learning FFmpeg

• Explore the Help Option: ffmpeg comes with extensive documentation. Run ffmpeg -h to see an overview or ffmpeg -h full for detailed options.
• Experiment with Different Options: ffmpeg has numerous options and filters that allow for complex processing. Experimenting is a great way to learn.
• Consult the FFmpeg Documentation: The FFmpeg Documentation is a comprehensive resource for understanding all of its capabilities.

Conclusion

This guide provides a starting point for using ffmpeg, covering some basic tasks. ffmpeg is incredibly powerful, and mastering it can take time. Start with these fundamental tasks, and gradually explore more complex commands and options as you become more comfortable with the tool.