clip last n seconds from recording in progress - usage "clipgameplay <footage directory> <seconds>"

clip

#!/bin/bash

# the directory containing gameplay footage
DIR=$1
# the number of seconds to clip
SECONDS=$2

if [ -z $DIR ]; then
    echo "No directory given"
    # exit - this must be provided
    exit 1
elif [[ ! -d "$DIR" ]]; then
    echo "Not a directory"
    # exit - this must be provided
    exit 1
fi

if [ -z $SECONDS ]; then
    # default to 20
    SECONDS=20
fi

# cd into the directory containing gameplay footage
cd $DIR

# get the first file with "gameplay" in the name
FILENAME=`find $1 -name "gameplay*" -type f -print0 | xargs -0 stat --format '%n' | sort -nr | cut -d: -f2- | head -1`
# extract the date from filename
FULL_DATE=$(echo "$FILENAME" | grep -Eo '[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}_[[:digit:]]{2}.[[:digit:]]{2}.[[:digit:]]{2}')
# get the date from the extracted date string
DATE=$(echo "$FULL_DATE" | grep -Eo '[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}')
# get the time from extracted date string
TIME=$(echo "$FULL_DATE" | grep -Eo '[[:digit:]]{2}.[[:digit:]]{2}.[[:digit:]]{2}$' | sed -r 's/\.+/:/g')
# put them together and convert them to a timestamp
TIMESTAMP=`date --date="$DATE $TIME" +"%s"`
# get the current timestamp
CURRENT_TIMESTAMP=`date +%s`
# get how many seconds ago the timestamp is
SECONDS_AGO=`expr $CURRENT_TIMESTAMP - $TIMESTAMP`
# get the starting point
STARTING_POINT=`expr $SECONDS_AGO - $SECONDS`
# for trimming it down to the precise amount of seconds
NEGATIVE_SECONDS=`expr $SECONDS \* -1`

# sleep to sync with end of video
sleep 2

if [ "$STARTING_POINT" -lt 0 ]
then
    # this must not be negative
    STARTING_POINT=0
fi

# make the directory for clips
mkdir -p clip

FILEPATH="$DIR/clip/$CURRENT_TIMESTAMP.mkv"
TMP_FILEPATH="$DIR/clip/$CURRENT_TIMESTAMP-temp.mkv"

# make the clip
ffmpeg -ss $STARTING_POINT -i $FILENAME -t $SECONDS -c copy -c:v copy -c:a copy -preset:v ultrafast $FILEPATH

VIDEO_LENGTH=`ffprobe -i $FILEPATH -show_entries format=duration -v quiet -of csv="p=0"`

if [ "$VIDEO_LENGTH" -lt "$SECONDS" ]
then
    # video is already short enough
    exit 1
fi

# take the last seconds from the clip created
ffmpeg -sseof $NEGATIVE_SECONDS -i $FILEPATH -c:v copy -c:a copy -preset:v ultrafast $TMP_FILEPATH

# then replace the previous clip with the more precise trimmed down clip
mv $TMP_FILEPATH $FILEPATH