.dotfiles/zsh/ffmpeg

#--------------------------------
# filename:     /zsh/ffmpeg
#--------------------------------

# Original script: https://yohanes.gultom.me/2016/05/21/bash-script-to-batch-convert-mkv-to-mp4-linux/
# Rewritten with ChatGPT 🙈

function ff-mp4 () {
        local findpath="${1:-.}"
        local file_list=()
        local temp_file=$(mktemp)

        # Find all video files and write them to a temporary file
        find "$findpath" \( -iname '*.mkv' -o -iname '*.flv' -o -iname '*.mov' -o -iname '*.mp4' \) -print0 > "$temp_file"

        # Read the file contents into the file_list array
        while IFS= read -r -d $'\0' file; do
                file_list+=("$file")
        done < "$temp_file"
        rm "$temp_file" # Delete the temporary file

        # Process each file in the file_list array
        local num_files=${#file_list[@]}
        local counter=1
        for file in "${file_list[@]}"; do
                local dir=$(dirname "$file")
                local file_name=$(basename "$file")
                local name="${file_name%.*}"
                local ext="${file_name##*.}"

	echo "Processing file [$counter/$num_files]: $file_name"
	counter=$((counter+1))

        # Re-container the video file to mp4 using ffmpeg
        ffmpeg -hide_banner -loglevel error -i "$file" -map 0 -c copy -pix_fmt yuv420p -movflags faststart "$dir/temp_$name.mp4"

        # Rename the original file and move the new mp4 file to its place
        mv -n "$file" "$dir/_$file_name"
        mv -n "$dir/temp_$name.mp4" "$dir/$file_name"

done
}

# Recompress input MP4 to 720p MP4 (copy audio)
ff-recompress720p() {
        for input in *.mp4; do
        if [[ -f "$input" ]]; then
                tempfile="temp_${input%.mp4}"
                ffmpeg -hide_banner -i "$input" -map 0 -c:v libx264 -crf 18 -vf scale=1280:-2 -preset slow -tune film -x264-params "ref=5:bframes=5:crf-max=25:qpmax=34:level=3.1:b-adapt=2:direct=auto:deblock=-1,-1:analyse=all:me=umh:subme=9:trellis=2:psy-rd=1,0.15:vbv-bufsize=17500:vbv-maxrate=17500:rc-lookahead=60" -c:a copy -movflags faststart "$tempfile.mp4"

                if [[ $? -eq 0 ]]; then
                        mv "$input" "_$input"
                        mv "$tempfile.mp4" "$input"
                        echo "Conversion successful: $input"
                else
                        echo "Conversion failed for: $input"
                fi
        fi
done
}

# ffmpeg-convert
# source: https://yohanes.gultom.me/2016/05/21/bash-script-to-batch-convert-mkv-to-mp4-linux/
function ff-ac3-to-stereo() {
        findpath=$1
        : "${findpath:="."}"
        find "$findpath" \( -iname '*.mkv' -o -iname '*.flv' -o -iname '*.mov' -o -iname '*.mp4' \) | while read -r f ; do
                dir=$(dirname "$f");
                file=$(basename "$f");
                name="${file%.*}";
                ext="${file##*.}";

                ffmpeg -hide_banner -loglevel error -i "$f" -map 0 -c:v copy -c:a libfdk_aac -b:a 192k -ac 2 -af volume=2 -movflags faststart "$dir/temp_$name.mp4";

                mv "$f" "$dir/_$file";
                mv "$dir/temp_$name.mp4" "$dir/$file";
        done
}

# ffmpeg audio-to-ac3
function ff-input-to-ac3() {
	ffmpeg -i "$1" -movflags faststart -map 0 -c:v copy -c:s copy -c:a ac3 -b:a 448k "temp_$1"
	mv "$1" "_$1" && mv "temp_$1" "$1"	
}

# ffmpeg fix 16:9 AR
function ff-ar16-9() {	
	ffmpeg -i "$1" -c copy -map 0 -bsf:v "h264_metadata=sample_aspect_ratio=4/3" -aspect 16:9 -pix_fmt yuv420p -movflags faststart "temp_$1"
        mv "$1" "_$1" && mv "temp_$1" "$1"
}

# ffmpeg fix 5:4 AR
function ff-ar5-4() {
        ffmpeg -i "$1" -c copy -map 0 -bsf:v "h264_metadata=sample_aspect_ratio=1/1" -aspect 5:4 -pix_fmt yuv420p -movflags faststart "temp_$1"
        mv "$1" "_$1" && mv "temp_$1" "$1"
}

# ffmpeg fix 4:3 AR
function ff-ar4-3() {
        ffmpeg -i "$1" -c copy -map 0 -bsf:v "h264_metadata=sample_aspect_ratio=1/1" -aspect 4:3 -pix_fmt yuv420p -movflags faststart "temp_$1"
        mv "$1" "_$1" && mv "temp_$1" "$1"
}

# ffmpeg fix AR ($1 = file, $2 1/1, $4:3) 
function ff-ar-custom() {
	if [ $# -lt 3 ]; then
                >&2 echo "Not enough arguments (\$1 = 'file', \$2 '1/1', \$3 '4:3')"
                return 0
	else
        ffmpeg -i "$1" -c copy -map 0 -bsf:v "h264_metadata=sample_aspect_ratio=$2" -aspect $3 -pix_fmt yuv420p -movflags faststart "_$1"
	fi
}

# ffmpeg fix Non-monotonous DTS
function ff-dts() {
	ffmpeg -fflags +igndts -i "$1" -c copy -pix_fmt yuv420p -movflags faststart "temp_$1"
        mv "$1" "_$1" && mv "temp_$1" "$1"
}

## ffmpeg wma-to-m4a
function ff-wma-m4a() {
        findpath=$1
        : "${findpath:="."}"
        find "$findpath" -name '*.wma' | while read -r f ; do
                dir=$(dirname "$f");
                file=$(basename "$f");
                name="${file%.*}";
                ext="${file##*.}";

                ffmpeg -hide_banner -loglevel error -i "$f" -map 0 -vn -b:a 192k -c:a libfdk_aac "$dir/temp_$name.mp4";

                mv "$f" "$dir/_$file";
                mv "$dir/temp_$name.mp4" "$dir/$file";
        done
}

## ffmpeg cut X seconds from start
function ff-cutstart {
        local time="${2:-00:00:08.590}"
        mv "$1" "_$1"
        ffmpeg -ss $time -i "_$1" -map 0 -c copy -movflags faststart "$1"
}

## ffmpeg cut X seconds from start
function ff-cutend {
        local time="${2:-24.250}"
        duration=`ffprobe -v error -show_entries format=duration -of csv=p=0 "$1"`
        duration=`bc --expression=$duration-$time`
        mv "$1" "_$1"
        ffmpeg -ss 00:00:00 -to $duration -i "_$1" -map 0 -c copy -movflags faststart "$1"
}