user/rand_media_pl.sh

   1 #!/usr/bin/env bash
   2 # Description:
   3 #   - Finds audio and video files with specified extensions up to a max depth of 8.
   4 #   - Uses ffprobe to measure their durations.
   5 #   - Creates a playlist starting at a random location within the total runtime.
   6 #   - Stores durations and file paths in a dotfile for faster subsequent runs.
   7 #   - Prompts the user whether to use the cached data or regenerate it.
   8 #   - Uses an EDL file to specify the starting offset for the first file.
   9 # Usage: rand_media_pl.sh [DIR]
  10 # Version: 0.1.0
  11 # Dependencies: Bash 4, ffprobe, mpv, bc, shuf, GNU Parallel
  12
  13 yell() { echo "$0: $*" >&2; } # Print script path and all args to stderr
  14 die() { yell "$*"; exit 111; } # Same as yell() but exits with code 111
  15 must() { "$@" || die "cannot $*"; } # Runs args as command, reports args if command fails
  16
  17 # Configurable variables
  18 SEARCH_DIR="${1:-.}"  # Default to current directory if no argument is provided
  19 MAX_DEPTH=8;
  20 EXTENSIONS=("*.flac" "*.mp3" "*.opus" "*.m4a" "*.m4b" "*.mp4" "*.mkv" "*.webm");
  21 CACHE_FILE=".playlist_cache";
  22
  23 declare -gA file_durations;
  24 declare total_duration;
  25
  26 # Function to prompt the user
  27 prompt_yes_no() {
  28     yell "STATUS: User input required.";
  29     local prompt_message="$1";
  30     local user_input;
  31     while true; do
  32         read -rp "$prompt_message [y/n]: " user_input;
  33         case "$user_input" in
  34             [Yy]*) return 0 ;;
  35             [Nn]*) return 1 ;;
  36             *) echo "Please answer yes or no." ;;
  37         esac;
  38     done;
  39 };
  40
  41 # Function to find files with specified extensions
  42 find_media_files() {
  43     yell "STATUS: Finding media files.";
  44     local find_cmd=("find" "-L" "$SEARCH_DIR" "-maxdepth" "$MAX_DEPTH" "-type" "f" "(");
  45     for ext in "${EXTENSIONS[@]}"; do
  46         find_cmd+=("-iname" "$ext" "-o");
  47     done;
  48     # Remove the last "-o" and add ")";
  49     unset 'find_cmd[-1]';
  50     find_cmd+=(")");
  51     "${find_cmd[@]}";
  52 };
  53
  54 # Function to generate the playlist cache
  55 generate_playlist_cache() {
  56     yell "Generating playlist cache. This may take a while..."
  57     # Initialize or empty the cache file
  58     : > "$CACHE_FILE";  # Truncate or create the cache file
  59
  60     total_duration=0;
  61     while IFS= read -r file; do
  62         # Get the duration using ffprobe
  63         duration=$(ffprobe -v error -show_entries format=duration \
  64             -of default=noprint_wrappers=1:nokey=1 "$file");
  65         declare -p file duration 1>&2;  # Debugging statement
  66
  67         # Validate the duration
  68         if [[ -n "$duration" && "$duration" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
  69             # Append the file path and duration to the cache file
  70             printf "%s|%s\n" "$file" "$duration" >> "$CACHE_FILE";
  71             total_duration=$(echo "$total_duration + $duration" | bc);
  72         else
  73             yell "WARNING: Invalid duration '$duration' for file '$file', skipping." 1>&2;
  74         fi;
  75     done < <(find_media_files | parallel readlink -f '{}' | sort -u; );
  76
  77     total_duration_s="$(printf "%.1f" "$total_duration"; )";
  78     total_duration_h="$(echo "scale=1; $total_duration / 3600" | bc -l; )";
  79
  80     yell "Total duration of playlist: ${total_duration_s} seconds (${total_duration_h} hours).";
  81 };
  82 # Function to read the playlist cache
  83 read_playlist_cache() {
  84     # Input: file_durations associative array
  85     #        total_duration scalar
  86     yell "STATUS: Reading playlist cache."
  87
  88     total_duration=0
  89     while IFS='|' read -r file duration; do
  90         declare -p file duration 1>&2  # Debugging statement
  91
  92         # Validate the duration
  93         if [[ -n "$duration" && "$duration" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
  94             file_durations["$file"]="$duration"
  95             total_duration=$(echo "$total_duration + $duration" | bc)
  96         else
  97             yell "WARNING: Invalid duration '$duration' for file '$file', skipping." 1>&2
  98         fi
  99     done < "$CACHE_FILE";
 100 };
 101 # Function to get byte count of file name
 102 prepend_path_bc() {
 103     # Desc: Prepends a file path with %[path bytecount]%
 104     # Usage: prepend_filename_bc [FILE]
 105     # Input:  arg1    str  file path
 106     # Output: stdout  str  %[int path length]%path
 107     # Example: 'foo.txt' yields '%7%foo.txt'
 108     # Depends: GNU Coreutils 8.32 (for 'wc')
 109     #          BK-2020-03: yell(), die(), must()
 110     # Ref/Attrib: See “Syntax of mpv EDL files” https://github.com/mpv-player/mpv/blob/master/DOCS/edl-mpv.rst#syntax-of-mpv-edl-files
 111     fin="$1";
 112
 113     if [[ ! -f "$fin" ]]; then
 114         yell "WARNING:File does not exist:${fin}";
 115     fi;
 116
 117     bytecount="$(printf "%s" "$fin" | wc -c; )";
 118     re='[0-9]';
 119     if [[ ! "$bytecount" =~ $re ]]; then
 120         die "FATAL:Not an int:${bytecount}; $(declare -p fin bytecount)";
 121     fi;
 122     printf "%%%s%%%s" "$bytecount" "$fin";
 123 };
 124
 125 # Main script
 126 if [[ -f "$CACHE_FILE" ]]; then
 127     if prompt_yes_no "Playlist cache detected. Do you want to use it? (Faster)"; then
 128         read_playlist_cache;
 129     else
 130         generate_playlist_cache;
 131         read_playlist_cache;
 132     fi;
 133 else
 134     generate_playlist_cache;
 135     read_playlist_cache;
 136 fi;
 137
 138 # Check if any files were found
 139 if [[ ${#file_durations[@]} -eq 0 ]]; then
 140     declare -p file_durations 1>&2;
 141     die "FATAL: No media files found.";
 142 fi;
 143
 144 # Ensure total_duration is not empty
 145 if [[ -z "$total_duration" ]]; then
 146     die "FATAL: total_duration is empty.";
 147 fi;
 148
 149 # Convert total_duration to an integer
 150 total_duration_int=$(printf "%.0f" "$total_duration");
 151
 152 # Check if total_duration_int is a valid integer
 153 if ! [[ "$total_duration_int" =~ ^[0-9]+$ ]]; then
 154     die "FATAL: total_duration_int is not a valid integer.";
 155 fi;
 156
 157 # Generate a random integer between 0 and total_duration_int - 1
 158 random_point=$(shuf -i 0-$((total_duration_int - 1)) -n1)
 159 yell "DEBUG: total_duration=$total_duration, total_duration_int=$total_duration_int, random_point=$random_point" 1>&2;
 160
 161 # Get sorted list of files
 162 mapfile -t sorted_files < <(printf '%s\n' "${!file_durations[@]}" | sort; );
 163
 164 # Find the file and offset corresponding to the random starting point
 165 accumulated_duration=0;
 166 accumulated_duration_int=0;
 167
 168 for idx in "${!sorted_files[@]}"; do
 169     file="${sorted_files[$idx]}";
 170     duration="${file_durations["$file"]}";
 171     declare -p idx file duration accumulated_duration 1>&2;  # Debugging statement
 172
 173     # Validate the duration
 174     if [[ -n "$duration" && "$duration" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
 175         new_accumulated_duration=$(echo "$accumulated_duration + $duration" | bc)
 176         # Convert accumulated durations to integers for comparison
 177         accumulated_duration_int=$(printf "%.0f" "$accumulated_duration")
 178         new_accumulated_duration_int=$(printf "%.0f" "$new_accumulated_duration")
 179     else
 180         yell "WARNING: Invalid duration '$duration' for file '$file', skipping." 1>&2
 181         continue
 182     fi
 183
 184     if (( random_point < new_accumulated_duration_int )); then
 185         offset=$(echo "$random_point - $accumulated_duration_int" | bc; );
 186         yell "Starting playback from $offset seconds into file: $file";
 187
 188         # Create an EDL file
 189         edl_file=$(mktemp);
 190         yell "DEBUG:EDL file at:${edl_file}"; # debug
 191         echo "# mpv EDL v0" > "$edl_file";
 192
 193         # Add first file to start playback at random offset position
 194         file_bc="$(prepend_path_bc "$file")"; # See https://github.com/mpv-player/mpv/blob/master/DOCS/edl-mpv.rst#syntax-of-mpv-edl-files
 195         printf '%s,%s\n' "$file_bc" "$offset" >> "$edl_file";
 196
 197         # Append the rest of the files
 198         declare -p file offset idx sorted_files edl_file 1>&2; # debug
 199         for (( i=idx+1; i<${#sorted_files[@]}; i++ )); do
 200             next_file="${sorted_files[$i]}";
 201             next_file_bc="$(prepend_path_bc "$next_file")";
 202             yell "STATUS:Adding:$next_file";
 203             printf '%s\n' "$next_file_bc" >> "$edl_file";
 204         done;
 205
 206         # Start playback using mpv
 207         mpv "$edl_file" || exit 1;
 208
 209         # Securely delete the EDL file
 210         if [[ -n "$edl_file" && -f "$edl_file" ]]; then
 211             rm "$edl_file";
 212             exit 0;
 213         else
 214             die "FATAL: edl_file is either unset or not a valid file, skipping deletion.";
 215         fi;
 216     fi;
 217     accumulated_duration="$new_accumulated_duration";
 218     accumulated_duration_int="$new_accumulated_duration_int";
 219 done;
 220
 221 die "FATAL: Could not find file corresponding to random point.";