Why does this script exit after the file it converts?

I’m running this in a backgrounded container to convert level 5.2 h264 files down to level 5.1. It’s working as expected in terms of all the checks for when to convert or not. But after the first file it comes across to convert, it performs the conversion, writes the final converted -> ... messages, and then exits the loop with the finished run message. I run the container again it dutifully finds the next file and converts it and cleanly exits again. I’ve done loads of other shell script looping over files using the while read do <<< $(find ...) pattern (to handle file paths/names with spaces and never had this issue. container command: docker run -d --rm --name ffmpeg -v ${HOME}/.local/bin:/scripts -v /volume1/media:/media --entrypoint /scripts/reduce_level.sh linuxserver/ffmpeg:latest -s /media/Movies -l /media/reduce_level.log script #!/usr/bin/env bash # Find all .mp4 and .mkv files with h264 video streams whose level > 5.1 (ffprobe reports levels like 51 or 5.1) # and re-encode the video to level 5.1 keeping the same profile (if available). # Audio and subtitle streams are passed through (copied). # # Usage: # ./reduce_level.sh # actually convert # ./reduce_level.sh --dry-run # show the ffmpeg commands without running them # # Requirements: ffprobe and ffmpeg in PATH. set -euo pipefail log() { local log_level=$1 # A string representing the log level provided by the user when calling the function local message=$2 # A string representing the message provided by the user when calling the function local script_name=$(basename $0) # The name of the script that is running local timestamp=$(date +"%Y-%m-%d %H:%M:%S") # The current date and time at the time the function is called if (( VERBOSE )); then echo -e "$timestamp [$log_level] [$script_name] $message" | tee -a "${LOGFILE}" else echo -e "$timestamp [$log_level] [$script_name] $message" >> "${LOGFILE}" fi } PARSED_ARGS=$(getopt -o dl:s:v --long dry-run,log-file:,start-dir:,verbose -- "$@") eval set -- "${PARSED_ARGS}" # Will be overwridden if arguments provided DRY_RUN=0 VERBOSE=0 while true; do case "$1" in -d | --dry-run ) DRY_RUN=1 shift ;; -l | --log-file ) LOGFILE="$(realpath "$2")" shift 2 ;; -s | --start-dir ) START_DIR="$(realpath "$2")" shift 2 ;; -v | --verbose ) VERBOSE=1 shift ;; -- ) shift break ;; * ) log ERROR "Unsupported argument $1" exit 1 ;; esac done # Defaults if arguments not provided START_DIR="${START_DIR:-$(pwd)}" LOGFILE="${LOGFILE:-${START_DIR}/$(basename "${0/.sh/.log}")}" # Verify inputs [[ ! -d "${START_DIR}" ]] && { log ERROR "Could not find starting directory \"${START_DIR}\""; exit 1; } [[ ! -d "$(dirname "${LOGFILE}")" ]] && { log ERROR "Could not find log file directory \"$(dirname "${LOGFILE}")\""; exit 1; } log INFO "\n\n---------------- Starting run ----------------\n\n" while read f; do { log INFO "Checking: $f" # Get codec_name, profile and level for each video stream as separate lines (triplets) probe_output=$(ffprobe -v error -show_format -show_streams -select_streams v -of json "$f") if [[ "{}" == "$(jq -r '.' <<< ${probe_output})" ]]; then log INFO " no video streams found or ffprobe failed" continue fi if [[ 1 -lt $(jq -r '.streams | length' <<< ${probe_output}) ]]; then log WARN " more than one video stream found, skipping" continue fi need_convert=0 picked_profile="" # Iterate over the probe output three lines at a time (codec, profile, level) # We use a here-string so the loop runs in the current shell (no subshell) and doesn't need mapfile/readarray. bit_rate_bps=$(jq -r '.format.bit_rate' <<< ${probe_output}) bit_rate_mbps=$(awk -v br=${bit_rate_bps} 'BEGIN{printf("%2.2f", br/1000000)}') codec=$(jq -r '.streams[0].codec_name' <<< ${probe_output}) height=$(jq -r '.streams[0].height' <<< ${probe_output}) level_raw=$(jq -r '.streams[0].level' <<< ${probe_output}) profile=$(jq -r '.streams[0].profile' <<< ${probe_output}) width=$(jq -r '.streams[0].width' <<< ${probe_output}) # skip if codec not h264 if [[ "$codec" != "h264" && "$codec" != "libx264" ]]; then log INFO " video streams found are not h264/libx264" continue fi # Only process 4k files if [[ ${width} -gt ${height} ]]; then resolution=${height} else resolution=${width} fi if [[ ${resolution} -lt 2160 ]]; then log INFO " ok (video resolution is under 4k)" continue fi # normalize level: # ffprobe may return "51" or "5.1"; convert "5.1" -> 51 (integer) for comparison. if [[ -z "$level_raw" ]]; then level_int=0 elif [[ "$level_raw" == *.* ]]; then # multiply by 10 and floor level_int=$(awk -v l="$level_raw" 'BEGIN{printf("%d", l*10)}') else # ensure base-10 integer level_int=$((10#$level_raw)) 2>/dev/null || level_int=0 fi if (( level_int > 51 )); then # look for othe files of same name root, but with different bit rate froot=$(sed -r "s,(.*)\[[0-9\.]+ Mbps\]\.${f##*.},\1," <<< $f) fcount=$(/bin/ls -1 "${froot}"*.${f##*.} | wc -l) if [[ 2 -le $fcount ]]; then log INFO " Found other files with same name root and different bitrate, skipping" continue fi need_convert=1 # prefer first non-empty profile we find if [[ -z "$picked_profile" && -n "$profile" ]]; then picked_profile="$profile" fi fi if (( need_convert )); then log INFO " will convert (found h264 level > 5.1). profile='${picked_profile:-(none)}'" # create a unique temporary file in the same directory out="${f%.*}.level51" tmpdir="$(dirname "${out}.${f##*.}")" tmptmpl="$(basename "${out}").tmp.XXXXXX" tmpfile="$(mktemp "$tmpdir/$tmptmpl")" || { log WARN " failed to create temp file"; continue; } rm -f -- "$tmpfile" # remove placeholder so ffmpeg can create it with correct container ext tmp="${tmpfile}.${f##*.}" if [[ -n "$picked_profile" ]]; then ffargs=( -i "$f" -v error -map 0 -c:a copy -c:s copy -c:v libx264 -profile:v "$picked_profile" -level 5.1 -preset slow -crf 18 -y "$tmp" ) else ffargs=( -i "$f" -v error -map 0 -c:a copy -c:s copy -c:v libx264 -level 5.1 -preset slow -crf 18 -y "$tmp" ) fi if (( DRY_RUN )); then log INFO " DRY RUN -- Running: ffmpeg ${ffargs[*]}" continue fi log INFO " Running: ffmpeg ${ffargs[*]}" if ffmpeg "${ffargs[@]}"; then bit_rate_reduced=$(ffprobe -v error -of json -show_format -show_entries format=bit_rate "$tmp" | jq -r '.format.bit_rate') bit_rate_reduced_mbps=$(awk -v br=${bit_rate_reduced} 'BEGIN{printf("%2.2f", br/1000000)}') mv -v -- "$f" "${f%.*}.[${bit_rate_mbps} Mbps].${f##*.}" mv -v -- "$tmp" "${f%.*}.[${bit_rate_reduced_mbps} Mbps].${f##*.}" log INFO " converted -> $f" else log WARN " ffmpeg failed for $f" >&2 rm -f -- "$tmp" fi else log INFO " ok (no h264 stream with level > 5.1)" fi } done <<< $(find "${START_DIR}" -type f -iname '*.mp4' -o -iname '*.mkv') log INFO "\n\n---------------- Finished run ----------------\n\n"