The mp4box command is a tool that is part of the MPEG-4 Systems Toolbox. It is used to mux streams into an MP4 container. With mp4box, users can display information about an existing MP4 file, add subtitles to an MP4 file, and combine audio and video from different files into a single MP4 file.

Use case 1: Display information about an existing MP4 file

Code:

mp4box -info path/to/file

Motivation: Displaying information about an existing MP4 file can be useful for troubleshooting or inspecting the file details. It provides details such as the file format, duration, bitrate, media streams, and metadata.

Explanation:

• mp4box: The command itself.
• -info: The option to display information about the MP4 file.
• path/to/file: The path to the MP4 file.

Example Output:

* Movie Info *
        Timescale 1000 - Duration 00:01:30.000
        Fragmented File: no
        File suitable for progressive download (moov before mdat)
        File Brand isom - version 1
        Created: Mon Apr 12 15:53:36 2022

File has 1 track(s)
...

Use case 2: Add an SRT subtitle file into an MP4 file

Code:

mp4box -add input_subs.srt:lang=eng -add input.mp4 output.mp4

Motivation: Adding subtitles to an MP4 file allows viewers to have captions for the video content. This is particularly important for accessibility purposes or when content is in a language that the viewer may not understand.

Explanation:

• mp4box: The command itself.
• -add: The option to add a file to the MP4 container.
• input_subs.srt:lang=eng: The SRT subtitle file to be added. The :lang=eng argument specifies the language of the subtitle file as English.
• -add: The option to add another file to the MP4 container.
• input.mp4: The input MP4 file to which the subtitle will be added.
• output.mp4: The output MP4 file with the added subtitle.

Example Output: None (Successful execution produces no output)

Use case 3: Combine audio from one file and video from another

Code:

mp4box -add input1.mp4#audio -add input2.mp4#video output.mp4

Motivation: Combining audio from one file and video from another allows users to synchronize audio and video content in a single MP4 file. This is commonly used in video editing or multimedia production workflows.

Explanation:

• mp4box: The command itself.
• -add: The option to add a file to the MP4 container.
• input1.mp4#audio: The input MP4 file (input1.mp4) from which the audio track will be extracted and added to the output.
• -add: The option to add another file to the MP4 container.
• input2.mp4#video: The input MP4 file (input2.mp4) from which the video track will be extracted and added to the output.
• output.mp4: The output MP4 file with the combined audio and video.

Example Output: None (Successful execution produces no output)

Conclusion:

The mp4box command is a versatile tool for working with MP4 files. It allows users to display information about existing MP4 files, add subtitles to MP4 files, and combine audio and video from different files into a single MP4 file. By understanding and using the various command options, users can effectively manage and manipulate MP4 files to suit their needs.