-n, --dry-run - Dry run mode: show what would be done without actually doing it
-f, --force - Force overwrite existing files
-h, --help - Print help information

How It Works

Video File Selection: The tool automatically finds the largest file (by file size) in the specified directory and uses it as the video file. This means:
- If there's only one video file, it will be selected
- If there are multiple files, the largest one (by size) will be selected
- Only files (not directories) are considered
- The selection is based on file size, not file name
Audio File Matching: The tool looks for an audio file with the same base name as the video file, but with .m4a extension. For example:
- Video: video.mp4 → Audio: video.m4a
- Video: episode_01.flv → Audio: episode_01.m4a
Processing Steps:
- Converts the audio file from M4A to AAC format
- Renames the original video file to original.<extension> as a backup
- Merges the video and audio into a single file
- The merged file is saved as <original_name>.mp4 (always MP4 format, regardless of input format)

Examples

# Merge video and audio in current directory
bilibili-merge

# Merge video and audio in a specific directory
bilibili-merge /path/to/video/directory

# Dry run to see what would be done
bilibili-merge -n

# Force overwrite existing files
bilibili-merge -f

# Combine options
bilibili-merge -n -f /path/to/directory

Notes

The tool requires ffmpeg to be installed and available in your PATH
By default, the tool will not overwrite existing files (use -f to force)
The original video file is automatically backed up as original.<extension>
The output file is always in MP4 format, regardless of the input video format
In dry-run mode, you'll get a shell script that you can review or execute manually