#!/bin/bash
maxwidth=1280
maxheight=720
bitrate="2M"
bufsize="1M"
# mp4 is better for streaming, mkv supports all sorts of mixed codecs and subtitles
#container="mkv"
container="mp4"
#encoder="libx264" #libx264 = CPU, better quality and much smaller filesize; h264_amf = AMD GPU; h265_nvenv = Nvidia GPU; h264_qsv = Intel GPU

# ffpb is a wrapper for ffmpeg to show a progress bar and the remaining time.
# install it using:
# pip install ffpb

# Check if ffpb is installed, then use it, otherwise use normal ffmpeg
builtin type -P "ffpb" &> /dev/null && binary="ffpb" || binary="ffmpeg"

# Check if a parameter is provided
if [ -z "$1" ]; then
    echo "Usage: "$(basename $0)" <file or files>"
    exit 1
fi

for input in "$@";
do
    if [ -f "$input" ]; then
        echo "Processing file: $input"
        output="${input%.*}.convertednew"
        # Check if mp4 container is desired and if subtitle is ASS format, then convert to srt, otherwise just copy subs
        subtitles_present=$(ffprobe -v error -select_streams s -show_entries stream=codec_name -of csv=p=0:s=x "$input")
        if [ "$subtitles_present" == "ass" ] && [ "$container" == "mp4" ];
        then
            subtitle_option="-c:s mov_text -metadata:s:s:0 language=en"
        else
            subtitle_option="-scodec copy"
        fi
        #check framerate to only ever reduce it and not increase it
        # ffprobe returns 25/1 or 24000/1001. result needs to be calculated and needs to be an integer, thus the bash $(( )).
        fps=$(ffprobe -v 0 -of csv=p=0 -select_streams v -show_entries stream=avg_frame_rate "$input" | sed 's#/# / #g')
        if [ "$fps" == "0 / 0" ]; then
            # some video files return 0 / 0 for avg_frame_rate, using r_frame_rate instead
            fps=$(ffprobe -v 0 -of csv=p=0 -select_streams v -show_entries stream=r_frame_rate "$input" | sed 's#/# / #g')
        fi
        fps=$(( $fps ))
        if [ $fps -gt 30 ]; then
            fps_option="-r 30"
        else
            fps_option=""
        fi
        #-c:a copy   #copies audio as is, but mp4 works best with aac and wma cannot be in mp4 files
        #$binary -i "$input" -vf scale=-2:$resolution -c:v libx264 -r 30 -crf 28 -c:a aac -scodec copy -b:v $bitrate -maxrate $bitrate -bufsize $bufsize "$output"
        # using complex filter to prevent upscaling and only ever downscale
        cmd=$binary' -i "'"$input"'" -filter_complex "scale=ceil(iw*min(1\,min('$maxwidth'/iw\,'$maxheight'/ih))/2)*2:-2" -c:v libx264 '$fps_option' -crf 28 -c:a aac '$subtitle_option' -b:v '$bitrate' -maxrate '$bitrate' -bufsize '$bufsize' -f '$container' "'"$output"'"'
        $binary -i "$input" -filter_complex "scale=ceil(iw*min(1\,min($maxwidth/iw\,$maxheight/ih))/2)*2:-2" -c:v libx264 $fps_option -crf 28 -c:a aac $subtitle_option -b:v $bitrate -maxrate $bitrate -bufsize $bufsize -f $container "$output"
        if [ $? -eq 0 ];
        then
            actualheight=$(ffprobe -v error -select_streams v -show_entries stream=height -of csv=p=0:s=x "$output")
            #output2="${output%.*}."$actualheight"p.$container"
            output2="${output//.convertednew/.$actualheight""p.}$container"
            mv "$output" "$output2"
            echo "Output file: $output2"
        else
            echo "An error occured. File not converted properly!"
            echo "Full ffmpeg command:"
            echo "${cmd//ffpb/ffmpeg}"
        fi
    fi
done

# When using in Nemo, it's helpful to force a key to be pressed before closing the terminal to see the status or any errors. Uncomment the following line:

#echo;read -rsn1 -p "Press any key to continue . . .";echo