#!/bin/bash
#
# This script is used by MediaTomb for transcoding support.
#
# Basic function that will transcode any input file into the target type
# 'dvd' ffmpeg supports
video_common() {
    local input="$1"
    local output="$2"
    exec ffmpeg -i "$input" -t dvd -y "$output"
}

# Basic function that will transcode any input file into the wav format
audio_common() {
    local input="$1"
    local output="$2"
    exec ffmpeg -i "$input" -f s16be -y "$output"
}

transcode_matroska() {
    local input="$1"
    local output="$2"
    local alang="$3"
    local slang="$4"

    audiofmt=`mediainfo --Inform="Audio;%Format%" "$1"`
    vidfmt=`mediainfo --Inform="Video;%Format%" "$1"`

    echo "Format: $vidfmt/$audiofmt"

    if [ "$vidfmt" = "AVC" ]; then
        # Already MP4, use it
        outvidfmt="copy -bsf h264_mp4toannexb"
        #outvidfmt="libx264 -level 41 -vpre normal"
    else
        outvidfmt="avc"
    fi

    if [ "$audiofmt" = "AAC" ]; then
        outaudfmt="copy"
    else
        outaudfmt="libmp3lame -ab 192k"
    fi
    exec ffmpeg -i "$1" -vcodec $outvidfmt -acodec $outaudfmt -copyts -sameq -f mpegts -y "$2"
}

# Our "main" function below.

USAGE="
This script is used by MediaTomb for transcoding support. It can also serve as
a script to transcode various files in a format suitable for streaming directly.

Synopsis:
 mediatomb-transcode [TRANSCODE FUNCTION OPTION] [GENERIC OPTIONS]

Generic Options:
 -h, --help                 Display this help message.
 -i, --input                Input file that is meant to be transcoded.
 -o, --output               Output file that will be read back by MediaTomb.
 --audio-lang               Specify ISO 639 language code to use for audio.
 --subtitle-lang            Specify ISO 639 language code to use for subtitles.

Transcode Function Options (one is required):
 --video-common             Perform generic video transcoding.
 --audio-common             Perform generic audio transcoding.
 --transcode-matroska       Used in transcoding matroska files.
"

while [ "$#" -gt "0" ]
do
    case "$1" in
        -i|--input)
            INPUT="$2"
            shift; shift;
            ;;
        -o|--output)
            OUTPUT="$2"
            shift; shift;
            ;;
        --video-common)
            USE_VIDEO_COMMON=1
            shift
            ;;
        --audio-common)
            USE_AUDIO_COMMON=1
            shift
            ;;
        --transcode-matroska)
            USE_TRANSCODE_MATROSKA=1
            shift
            ;;
        --audio-lang)
            ALANG="$2"
            shift; shift;
            ;;
        --subtitle-lang)
            SLANG="$2"
            shift; shift;
            ;;
        -h|--help|*)
            echo "${USAGE}"
            exit 1
            ;;
    esac
done
 
# Perform specified function
if [ $USE_VIDEO_COMMON ]; then
    video_common "$INPUT" "$OUTPUT"
elif [ $USE_AUDIO_COMMON ]; then
    audio_common "$INPUT" "$OUTPUT"
elif [ $USE_TRANSCODE_MATROSKA ]; then
    transcode_matroska "$INPUT" "$OUTPUT" "$ALANG" "$SLANG"
else
    # Must specify one transcoding function
    echo "${USAGE}"
    exit 1
fi