#!/bin/sh
#
# Usage: livedump [FORMAT [BASESTEM [SESSIONPATTERN [SEGMENTPATTERN]]]]
#
#   Patterns are fed through "date +PATTERN"
#
# Examples: livedump
#           livedump dv ./dump /%Y%m%d/%H%M%S /%H%M%S
#           livedump dv-avi
#
#   First two examples effectively identical, using defaults.
#   Third example using AVI container instead
#
# Description: Save live source to file and append if interupted.
# By default captures IEC61883 DVCPRO stream from IEEE1394 (Firewire)
# device, some of which apparently sustaining streams max. 17 minutes.
#
# Depends: ffmpeg

set -eu

FORMAT=${1:-dv}
BASESTEM=${2:-./dump}
SESSIONPATTERN=${3:-/%Y%m%d/%H%M%S}
SEGMENTPATTERN=${4:-/%H%M%S}

case $FORMAT in
  dv)
	set -- -f iec61883 -i auto \
		-f dv -codec copy
	SUFFIX=dv
	;;
  dv-avi)
	set -- -f iec61883 -i auto \
		-f avi -codec copy
	SUFFIX=avi
	;;
  dv-nut)
	set -- -f iec61883 -i auto \
		-f nut -codec copy -f_strict experimental -syncpoints timestamped -write_index 0
	SUFFIX=mkv
	;;
esac


LINKPATH="$BASESTEM.$SUFFIX"
SESSIONSTEM=$(date +"$SESSIONPATTERN")
SESSIONPATH="$BASESTEM$SESSIONSTEM.$SUFFIX"

mkdir -p "$(dirname "$LINKPATH")" "$(dirname "$SESSIONPATH")"
touch "$SESSIONPATH"
[ -z "$LINKPATH" ] | ln -fs "$SESSIONPATH" "$LINKPATH"
while true; do
	SEGMENTSTEM=$(date +"$SEGMENTPATTERN")
	LOGPATH="$BASESTEM$SESSIONSTEM$SEGMENTSTEM.log"
	mkdir -p "$(dirname "$LOGPATH")"
	FFREPORT="file=$LOGPATH" \
	ffmpeg -hide_banner "$@" pipe: \
	>> "$SESSIONPATH"
done