Renaming the video or audio track inside an MKV container is possible using mkvmerge. The --track-name option allows you to set a custom name for any track (audio, video, or subtitle) in the container.

Here’s how you can rename a track within an MKV file:

Step 1: Identify Track Information

First, list the tracks to find the IDs and determine which track you want to rename:

mkvmerge -i input.mkv

Example output:

File 'input.mkv': container: Matroska
Track ID 0: video (V_MPEG4/ISO/AVC)
Track ID 1: audio (A_AC3) [English]
Track ID 2: audio (A_AAC) [French]
Track ID 3: subtitles (S_TEXT/UTF8) [French]

Step 2: Rename Tracks

Use the --track-name option to rename a specific track by its ID. For example:

mkvmerge -o output.mkv \
  --track-name 1:"English Audio" \
  --track-name 2:"French Commentary" \
  input.mkv

Explanation:

  • --track-name 1:"English Audio": Renames track ID 1 (the English audio track) to “English Audio”.
  • --track-name 2:"French Commentary": Renames track ID 2 (the French audio track) to “French Commentary”.
  • -o output.mkv: Specifies the output file.

Automate Renaming Tracks Based on Language

If you want to automatically rename tracks based on their language, you can use a script.

Bash Script Example

#!/bin/bash

# Directory to scan (default: current directory)
SEARCH_DIR="${1:-.}"

# Function to rename tracks
rename_tracks() {
    local file="$1"

    # Temporary file for mkvmerge commands
    local temp_file="temp.mkv"

    # Create mkvmerge options dynamically
    options=""
    while IFS= read -r line; do
        if [[ "$line" =~ Track\ ID\ ([0-9]+):.+language:\ ([a-z]{3}) ]]; then
            track_id="${BASH_REMATCH[1]}"
            lang="${BASH_REMATCH[2]}"
            options+="--track-name $track_id:\"${lang^} Track\" "
        fi
    done < <(mkvmerge -i "$file")

    # Apply the renaming
    if [[ -n "$options" ]]; then
        eval "mkvmerge -o \"$temp_file\" $options \"$file\""
        mv "$temp_file" "$file"
        echo "Renamed tracks in: $file"
    fi
}

# Process files recursively
find "$SEARCH_DIR" -type f -name "*.mkv" | while read -r file; do
    rename_tracks "$file"
done

How to Use:

  1. Save the script as rename_tracks.sh.
  2. Make it executable:
    chmod +x rename_tracks.sh
  3. Run it in the directory containing MKV files:
    ./rename_tracks.sh /path/to/directory

This script will:

  1. Scan each MKV file in the directory and subdirectories.
  2. Rename tracks based on their language (e.g., a track with language: eng becomes “Eng Track”).