Example Script using mythtranscode in fifodir mode

The script pipes the output of mythtranscode into ffmpeg, using libx264 to compress the video. The intended use is to set it up as a myth user job. the --passthrough option can currently be used only on 0.25.

#!/bin/bash

usage()
{
echo "Usage: $0 --chanid <channel id> --starttime <start time> --title <title> [--subtitle <sub title>] --outdir <directory> [options]";
echo "       $0 --chanid <channel id> --starttime <start time> -outfile <path> [options]";
echo "";
echo "       --chanid <channel id>                   The channel id for the recording. REQUIRED.";
echo "       --starttime <start time>                The start time for the recording. REQUIRED.";
echo "       --title <title>                         The title of the recording.";
echo "       --subtitle <subtitle>                   The subtitle of the recording.";
echo "       --outdir <path>                         The path of the directory for the output file. If one of";
echo "                                               --title --subtitle and --outdir are specified, then both --title and --outdir must";
echo "                                               be, and an output file will be chosen on their basis, avoiding";
echo "                                               conflict with existing files.";
echo "       --outfile <path>                        The exact path of the output file. ALTERNATIVE to";
echo "                                               --title --subtitle and --outdir.";
echo "       --vsize <width>x<height>                Scale video to specified resolution (the aspect ratio will";
echo "                                               be maintained using non-square pixels). If not specified,";
echo "                                               the source resolution will be maintained.";
echo "       --interlaced                            Assume the source is interlaced and maintain the interlace,";
echo "                                               provided --vsize not specified. If --vsize is specified then";
echo "                                               recode at double the frame rate.";
echo "       --passthrough                           Pass through the audio unaltered if possible.";
echo "       --quality <quality>                     Quality for compression (default 20.0)";
}

# Read arguments
unset CHANID
unset STARTTIME
unset TITLE
unset SUBTITLE
unset OUTDIR
unset OUTFILE
unset VSIZE
unset INTERLACED
unset PASSTHROUGH
unset QUALITY

ARGS=("$@")
I=0
while (( $I < $# )); do
{
    case ${ARGS[I]} in
        --chanid)      CHANID=${ARGS[I+1]};      I=$((I+2));;
        --starttime)   STARTTIME=${ARGS[I+1]};   I=$((I+2));;
        --title)       TITLE=${ARGS[I+1]};       I=$((I+2));;
        --subtitle)    SUBTITLE=${ARGS[I+1]};    I=$((I+2));;
        --outdir)      OUTDIR=${ARGS[I+1]};      I=$((I+2));;
        --outfile)     OUTFILE=${ARGS[I+1]};     I=$((I+2));;
        --vsize)       VSIZE=${ARGS[I+1]};       I=$((I+2));;
        --interlaced)  INTERLACED=1;             I=$((I+1));;
        --passthrough) PASSTHROUGH=1;            I=$((I+1));;
        --quality)     QUALITY=${ARGS[I+1]};     I=$((I+2));;
        *)             echo "Illegal option ${ARGS[I]}"; usage; exit 1;;
    esac
} done

# Check arguments make sense
if [[ ! -n $CHANID || ! -n $STARTTIME ]]; then
{
    echo "--chanid and --starttime required"
    usage
    exit 1
} fi

if [[ ! -n $OUTFILE && ! -n $OUTDIR ]]; then
{
    echo "Use either --outfile, or both --title --outdir, with optionally --subtitle"
    usage
    exit 1
} fi

if [[ -n $OUTFILE && ( -n $TITLE || -n $SUBTITLE || -n $OUTDIR) ]]; then
{
    echo "Use either --outfile, or both --title --outdir, with optionally --subtitle"
    usage
    exit 1
} fi

if [[ ( -n $TITLE || -n $OUTDIR || -n $SUBTITLE) && ( ! -n $OUTDIR || ! -n $TITLE ) ]]; then
{
    echo "Both --title and --outdir required for this mode of oparation"
    usage
    exit 1
} fi

if [[ -n $PASSTHROUGH ]]; then
{
    MYTHPASSTHROUGH="--passthrough"
}
else
{
    MYTHPASSTHROUGH=""
} fi

#Detect source formats
INFO=`mythtranscode -v general --chanid $CHANID --starttime $STARTTIME --fifoinfo $MYTHPASSTHROUGH`
OLDIFS=$IFS
IFS=$'\n'
LINES=( $INFO )
IFS=$OLDIFS

unset SVWIDTH
unset SVHEIGHT
unset SVASPECT
unset SVRATE
unset SAFMT
unset SACHANS
unset SARATE

for LINE in "${LINES[@]}" ; do
{
    case $LINE in
        *FifoVideoWidth*)         SVWIDTH=${LINE#*FifoVideoWidth };;
        *FifoVideoHeight*)        SVHEIGHT=${LINE#*FifoVideoHeight };;
        *FifoVideoAspectRatio*)   SVASPECT=${LINE#*FifoVideoAspectRatio };;
        *FifoVideoFrameRate*)     SVRATE=${LINE#*FifoVideoFrameRate };;
        *FifoAudioFormat*)        SAFMT=${LINE#*FifoAudioFormat };;
        *FifoAudioChannels*)      SACHANS=${LINE#*FifoAudioChannels };;
        *FifoAudioHz*)            SARATE=${LINE#*FifoAudioHz };;
        *FifoAudioSampleRate*)    SARATE=${LINE#*FifoAudioSampleRate };;
    esac
} done

if [[ ! -n $SVWIDTH || ! -n $SVHEIGHT || ! -n $SVASPECT || ! -n $SVRATE || ! -n $SAFMT || ! -n $SACHANS || ! -n $SARATE ]]; then
{
    echo "Failed to derive fifo formats"
    exit 1
} fi

SVSIZE=${SVWIDTH}x${SVHEIGHT}
if [[ $SVASPECT == 1.77778 ]]; then
{
    SVASPECT=16:9
}
elif [[ $SVASPECT == 1.33333 ]]; then
{
    SVASPECT=4:3
} fi
	
# Set up default values to unset variables
QUALITY=${QUALITY:-"20.0"}


# If --outfile not specified, use --outdir --title and --subtitle
if [[ ! -n $OUTFILE ]]; then
{
    EXT=".mp4"

    OBNAME="$OUTDIR/$TITLE"
    if [[ "$SUBTITLE" != "" ]]; then OBNAME+=" - $SUBTITLE"; fi

    I=1
    OUTFILE="$OBNAME$EXT"
    while [[ -a "$OUTFILE" ]]; do
    {
        I=$((I+1))
        OUTFILE="$OBNAME($I)$EXT"
    } done
} fi

# Can do pass through only with formats that ffmpeg will take as input
if [[ $SAFMT != ac3 && $SAFMT != dts && $SAFMT != mp3 ]]; then
{
    unset PASSTHROUGH
} fi

# Tell ffmpeg what audio to expect and what to do with it
if [[ -n $PASSTHROUGH ]]; then
{
    MYTHPASSTHROUGH="--passthrough"
    AUDINDESC="-f $SAFMT"
    AUDCODEC="copy"
}
else
{
    MYTHPASSTHROUGH=""
    AUDINDESC="-f s16le -ac 2"
    AUDCODEC="ac3 -ab 160k"
} fi

unset VSCALER
# If scaling use lanczos
if [[ -n $VSIZE ]]; then
{
    VSIZE=`echo $VSIZE | sed 's/x/:/'`
    # Lanczos seems to make the files bigger yet less sharp
    #VSCALER="-sws_flags lanczos"
} fi

unset VFILTER
unset VFLAGS
unset VRATE
if [[ -n $INTERLACED ]]; then
{
    if [[ -n $VSIZE ]]; then
    {
        # If scaling interlaced video, we must deinterlace first
        VFILTER="yadif=3,scale=$VSIZE"
        VRATE="-r `echo 2*$SVRATE | bc`"
    }
    else
    {
        # Otherwise maintain the interlace
        VFILTER=
        VFLAGS="-flags +ilme+ildct"
    } fi
}
else
{
    if [[ -n $VSIZE ]]; then
    {
        VFILTER="scale=$VSIZE"
    } fi
} fi

if [[ $SVHEIGHT == 1088 ]]; then
{
    if [[ -n $VFILTER ]]; then
    {
        VFILTER="crop=$SVWIDTH:1080:0:0,$VFILTER"
    }
    else
    {
        VFILTER="crop=$SVWIDTH:1080:0:0"
    } fi

} fi

if [[ -n $VFILTER ]]; then
{
    VFILTER="-vf $VFILTER"
} fi

# Create fifo dir
FIFODIR=/tmp/mythar$$
/bin/mkdir $FIFODIR
trap "rm -r $FIFODIR" EXIT

# Start mythtranscode outputting into the pipes
echo /usr/bin/mythtranscode --chanid $CHANID --starttime $STARTTIME --honorcutlist $MYTHPASSTHROUGH --fifodir $FIFODIR --cleancut &
/usr/bin/mythtranscode --chanid $CHANID --starttime $STARTTIME --honorcutlist $MYTHPASSTHROUGH --fifodir $FIFODIR --cleancut &

# Ensure we kill the background task at the end of the run
BACKGROUND=$!
trap "kill -9 $BACKGROUND" EXIT

# Wait for the background task to create the pipes
while [[ ! -e "$FIFODIR/audout" || ! -e "$FIFODIR/vidout" ]]; do /bin/sleep 1; done

echo /usr/bin/ffmpeg $AUDINDESC -i $FIFODIR/audout -f rawvideo -top 1 -pix_fmt yuv420p -s $SVSIZE -r $SVRATE -i $FIFODIR/vidout -threads 2 $VFILTER $VSCALER -vcodec libx264 -preset medium $VFLAGS -crf $QUALITY -bufsize 25000k -maxrate 20000k $VRATE -aspect $SVASPECT -acodec $AUDCODEC -ar $SARATE -f mp4 "$OUTFILE"
/usr/bin/ffmpeg $AUDINDESC -i $FIFODIR/audout -f rawvideo -top 1 -pix_fmt yuv420p -s $SVSIZE -r $SVRATE -i $FIFODIR/vidout -threads 2 $VFILTER $VSCALER -vcodec libx264 -preset medium $VFLAGS -crf $QUALITY -bufsize 25000k -maxrate 20000k $VRATE -aspect $SVASPECT -acodec $AUDCODEC -ar $SARATE -f mp4 "$OUTFILE"