feat(user/ffmpeg_parallel_encode.sh):Add parallel | ffmpeg script

diff --git a/user/ffmpeg_parallel_encode.sh b/user/ffmpeg_parallel_encode.sh
new file mode 100755 (executable)
index 0000000..ef0c4a7
--- /dev/null
+++ b/user/ffmpeg_parallel_encode.sh
@@ -0,0 +1,125 @@
+#!/bin/bash
+# Desc: Encodes video in parallel by processing time ranges directly from the input file.
+# Usage: ./ffmpeg_parallel_encode.sh input_video_file segment_duration_in_seconds
+# Version: 0.1.5
+
+# Limit the number of parallel jobs if necessary
+MAX_JOBS=8;   # Adjust this number based on your system's CPU capacity
+MAX_MEM=512M; # Adjust this number based on your system's memory
+
+set -e;  # Exit immediately if a command exits with a non-zero status
+set -u;  # Treat unset variables as an error
+
+yell() { echo "$0: $*" >&2; }  # Print script path and all args to stderr
+die() { yell "$*"; exit 111; }  # Same as yell() but exits with status 111
+must() { "$@" || die "cannot $*"; }  # Runs command, dies if it fails
+
+cleanup() {
+    if [[ -n "${temp_dir:-}" && -d "$temp_dir" ]]; then
+        echo "Cleaning up temporary files...";
+        rm -rf "$temp_dir";
+    fi
+    if [[ -n "${temp_list_file:-}" && -f "$temp_list_file" ]]; then
+        rm -f "$temp_list_file";
+    fi;
+}; # Function to clean up temporary files
+
+# Trap signals to ensure cleanup happens on script exit or interruption
+trap cleanup EXIT INT TERM;
+
+if [[ "$#" -ne 2 ]]; then
+    yell "Usage: $0 input_video_file segment_duration_in_seconds";
+    exit 1;
+fi;
+
+input_file="$1";
+segment_time="$2";
+
+# Check if input file exists
+if [[ ! -f "$input_file" ]]; then
+    die "Input file '$input_file' does not exist.";
+fi;
+
+base_name="$(basename "$input_file" | sed 's/\.[^.]*$//')";  # Strip extension
+segment_prefix="${base_name}_segment";
+encode_suffix="_encoded";
+declare -a segment_filenames;
+
+# Set umask to ensure files and directories are not accessible by others
+umask 0077;
+
+# Create a unique temporary directory for encoded files in the working directory
+timestamp="$(date +%s)";
+temp_dir="$(mktemp -d "${base_name}_${timestamp}_XXXXXX")";
+
+# Safety check: Ensure temp_dir is not empty and is a directory
+if [[ -z "${temp_dir}" || ! -d "${temp_dir}" ]]; then
+    die "Temporary directory creation failed.";
+fi;
+
+yell "Temporary directory created at $temp_dir";
+
+# Get the total duration of the input video in seconds
+yell "Getting total duration of input video...";
+duration_str="$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$input_file")";
+if [[ -z "$duration_str" ]]; then
+    die "Failed to get duration of input video.";
+fi;
+
+duration="$(printf "%.0f" "$duration_str")";  # Convert to integer seconds
+
+yell "Total duration: $duration seconds";
+
+# Calculate the number of segments
+num_segments=$(( (duration + segment_time - 1) / segment_time ));  # Ceiling division
+
+yell "Number of segments: $num_segments";
+
+# Generate start times and segment filenames, write to a temporary file
+yell "Preparing list of start times and filenames...";
+temp_list_file="$(mktemp -p "$temp_dir")";
+
+# Use a separator that is unlikely to appear in the data (ASCII Unit Separator)
+separator=$'\x1F';
+
+for (( i=0; i<num_segments; i++ )); do
+    start_time=$(( i * segment_time ));
+    segment_filename="${segment_prefix}_$(printf "%03d" "$i")${encode_suffix}.mp4";
+    segment_filepath="${temp_dir}/${segment_filename}";
+    printf '%s%s%s\n' "$start_time" "$separator" "$segment_filepath" >> "$temp_list_file";
+    segment_filenames[i]="$segment_filename";  # Store for later use
+done;
+
+# Encode segments in parallel without writing unencoded segments to disk
+yell "Encoding segments in parallel...";
+
+# Use GNU Parallel with the custom separator
+must parallel -j "$MAX_JOBS" --memsuspend "$MAX_MEM" --no-notice --bar --colsep "$separator" --arg-file "$temp_list_file" \
+    ffmpeg -hide_banner -i "$input_file" -ss '{1}' -t "$segment_time" -c:v libx264 -preset fast -crf 23 -c:a copy '{2}';
+
+# Step 3: Create a list file for concatenation
+segments_file="${temp_dir}/segments.txt";
+yell "Preparing for concatenation...";
+for (( i=0; i<num_segments; i++ )); do
+    segment_filename="${segment_filenames[i]}";
+    echo "file '$segment_filename'" >> "$segments_file";
+done;
+
+# Safety check: Ensure segments_file is not empty
+if [[ ! -s "$segments_file" ]]; then
+    die "Segments file is empty.";
+fi;
+
+# Step 4: Concatenate the encoded segments into a single output file
+output_file="${base_name}_output.mp4";
+yell "Concatenating encoded segments into $output_file...";
+(
+    cd "$temp_dir" || die "Failed to change directory to $temp_dir";
+    must ffmpeg -f concat -safe 0 -i "segments.txt" -c copy "$output_file";
+    mv "$output_file" ..
+)
+
+yell "Process completed successfully in ${SECONDS} seconds. Output video is $output_file";
+
+# Author: Steven Baltakatei Sandoval
+# License: GPLv3+