#!/usr/bin/env bash

set -euo pipefail

# Garmin Varia batch transcoder (macOS/Linux)

#

# Apple compatibility note:

# For HEVC outputs we explicitly set -tag:v hvc1 (not hev1), which is required

# for reliable QuickTime / Photos compatibility.

#

# Encoding strategy note:

# Do not derive output bitrate mechanically from fixed Garmin source sizes.

# Prefer CRF (software) or constrained VBR (hardware), as used below.

DEFAULT_SOURCE="."

DEFAULT_MODE="hardware"

DEFAULT_EXTENSIONS="mp4,mov,avi,m4v"

DEFAULT_CRF_HEVC=20

DEFAULT_CRF_H264=19

# We infer practical focal metadata from this single spec.

# 35mm-equivalent focal length is integer-only in EXIF, so we round to 7 mm.

GARMIN_DECLARED_FOV_DEG=140

GARMIN_INFERRED_FOCAL_MM="6.5"

GARMIN_INFERRED_FOCAL_35MM_MM="7"

DEST_DIR="$DEFAULT_SOURCE"

EXTENSIONS_CSV="$DEFAULT_EXTENSIONS"

CRF_OVERRIDE=""

OVERWRITE=true

DRY_RUN=false

RECURSIVE=true

SINGLE_FILE=""

VERBOSE=false

MOVE_SOURCE=false

SOURCE_PROVIDED=false

DEST_PROVIDED=false

AUTO_CREATED_STAGING_RAMDISK=false

AUTO_CREATED_STAGING_PATH=""

FIRST_ENCODE_STARTED_AT=0

DEBUG_TIMING_LIMIT=0

DEBUG_TIMING_FILES=0

DEBUG_TIMING_STOPPED=false

SOURCE_READABLE_MODE="normal"

APPLE_REPACK_FALLBACK=true

REPACKED_SOURCE_PATH=""

HAS_VIDEOTOOLBOX=false

HAS_LIBX265=false

HAS_LIBX264=false

ENCODER_KIND=""

VIDEO_CODEC=""

VIDEO_CRF=""

VIDEO_ARGS=()

FIND_EXT_EXPR=()

VIDEO_FILES=()

VIDEOS_PROCESSED=0

VIDEOS_SKIPPED=0

ERRORS=0

DESTINATION_FAILURES=0

OUTPUT_BYTES_PROCESSED=0

DURATION_TOLERANCE_SEC=1.0

INTERRUPT_COUNT=0

CURRENT_FFMPEG_PID=""

PROGRESS_LINE_OPEN=false

usage() {

  cat <<'EOF'

Usage:

  garmin_varia_transcode.sh [options]

Options:

  -s, --source, --input DIR       Source directory or single file (default: current directory)

  -d, --destination, --output DIR Destination directory (default: current directory)

                                  (falls back to destination if staging cannot be used)

                                  directory on macOS (default: 8192)

  --debug-timing N                Process at most N video files, then stop and print timing stats

  --crf N                         CRF value for quality/compat modes (lower = better; default: 20/19)

  --no-overwrite                  Skip files that already exist at destination (default: overwrite)

  --dry-run                       Print actions without writing files

  --no-recursive                  Process only the top-level source directory (default: recursive)

  --extensions LIST               Comma-separated video extensions (default: mp4,mov,avi,m4v)

  --verbose                       Log each operation with timestamp; show ffmpeg/ffprobe output

  --keep-going                    Continue after source-file failures (default: stop)

  --unattended                    Preset for long runs: --delete-source + --keep-going

  --no-apple-repack-fallback      Disable macOS avconvert fallback for unreadable MP4/MOV sources

  --apple-repack-fallback         Enable macOS avconvert fallback (default)

Encoding Modes:

  hardware   Uses hevc_videotoolbox (Apple Silicon / Intel Mac GPU). macOS only.

             ~4-5s per 30s clip, ~35W (measured on Apple Silicon MacBook Pro).

             Best choice when running on battery or transcoding large libraries.

             Output quality is good for dashcam/action footage.

             Falls back to an error on Linux or if videotoolbox is absent.

  auto       Like hardware on macOS with videotoolbox, otherwise falls back to quality,

             then compat. Safe cross-platform default when the machine is unknown.

  quality    Uses libx265 (software HEVC, CRF 20). Platform-independent.

             ~50s per 30s clip, ~80W (measured on Apple Silicon MacBook Pro).

             Best compression ratio and quality for archival, high-resolution, or visually

             complex sources (e.g. cinema, screen recordings).

             Overkill for dashcam footage; prefer hardware or auto for those.

  compat     Uses libx264 (software H.264, CRF 19). Maximum player compatibility.

             Use when the destination player cannot decode HEVC (older TVs, Android 4.x,

             web browsers without HEVC support). Larger files than HEVC modes.

Behavior:

  - Output is always .mp4 (H.264 or HEVC depending on mode, always Apple-compatible)

  - HEVC outputs are tagged hvc1 for QuickTime / Apple Photos compatibility

  - Garmin camera model is also mapped to standard Make/Model tags for compatibility

  - Inferred lens metadata is written from Garmin's declared 140-degree FOV

  - Transcoding encoder/mode is written in metadata (Software)

  - When --source points to a file, only that file is processed

Examples:

  ./garmin_varia_transcode.sh -s SampleFootage -d /Volumes/Archive

  ./garmin_varia_transcode.sh -s SampleFootage -d encoded --mode auto

  ./garmin_varia_transcode.sh -s clip.mp4 -d encoded --dry-run --verbose

  ./garmin_varia_transcode.sh -s SampleFootage -d encoded --mode quality --crf 18

  ./garmin_varia_transcode.sh -s SampleFootage -d encoded --mode compat

  ./garmin_varia_transcode.sh -s SampleFootage -d encoded --unattended

}

log_msg() {

  local level="$1"

  shift

  local ts

  ts="$(date '+%Y-%m-%d %H:%M:%S')"

  echo "[$ts] [$level] $*"

}

# Verbose-only log: suppressed in default quiet mode

vlog_msg() {

  [[ "$VERBOSE" == true ]] && log_msg "$@"

  return 0

}

log_progress_start() {

  ts="$(date '+%Y-%m-%d %H:%M:%S')"

}

log_progress_done() {

  local encode_elapsed_sec="$3"

    printf ' done in %ss (encode %ss)\n' "$real_elapsed_sec" "$encode_elapsed_sec"

    PROGRESS_LINE_OPEN=false

    return

  fi

  local input_file="$1"

  ts="$(date '+%Y-%m-%d %H:%M:%S')"

  local input_file="$1"

  local real_elapsed_sec="$2"

  local encode_elapsed_sec="$3"

  local ffmpeg_rc="$4"

  local ffmpeg_log="$5"

  if [[ "$PROGRESS_LINE_OPEN" == true ]]; then

    printf ' FAILED after %ss (encode %ss, rc=%s, log=%s)\n' "$real_elapsed_sec" "$encode_elapsed_sec" "$ffmpeg_rc" "${ffmpeg_log:-n/a}"

    PROGRESS_LINE_OPEN=false

    return

  fi

  local ts

  ts="$(date '+%Y-%m-%d %H:%M:%S')"

log_progress_skipped_unreadable() {

  local input_file="$1"

  if [[ "$PROGRESS_LINE_OPEN" == true ]]; then

    printf ' SKIPPED (unreadable/corrupted source)\n'

    PROGRESS_LINE_OPEN=false

    return

  fi

  local ts

  ts="$(date '+%Y-%m-%d %H:%M:%S')"

  log_msg "ERROR" "$*"

  exit 1

}

  INTERRUPT_COUNT=$((INTERRUPT_COUNT + 1))

  STOP_AFTER_CURRENT=true

  if [[ "$INTERRUPT_COUNT" -eq 1 ]]; then

    if [[ -n "$CURRENT_FFMPEG_PID" ]]; then

      log_msg "WARN" "Stop requested. Will stop after current file. Press Ctrl+C again to abort current encode immediately."

    else

      log_msg "WARN" "Stop requested. Exiting before next file."

    fi

    return

  fi

  if [[ -n "$CURRENT_FFMPEG_PID" ]]; then

    log_msg "WARN" "Force-stopping current encode (pid=$CURRENT_FFMPEG_PID)."

    kill -INT "$CURRENT_FFMPEG_PID" 2>/dev/null || true

  fi

}

run_ffmpeg_with_signal_guard() {

  (

    trap '' INT TERM

    exec "$@"

  ) &

  CURRENT_FFMPEG_PID=$!

  if wait "$CURRENT_FFMPEG_PID"; then

    CURRENT_FFMPEG_PID=""

    return 0

  fi

  local rc=$?

  CURRENT_FFMPEG_PID=""

  return "$rc"

}

  local sec="$1"

  local h m s

  h=$((sec / 3600))

  m=$(((sec % 3600) / 60))

  s=$((sec % 60))

  printf '%02d:%02d:%02d' "$h" "$m" "$s"

}

  local bytes="$1"

  awk -v b="$bytes" 'BEGIN {

    split("B KiB MiB GiB TiB PiB", u, " ");

    i = 1;

    while (b >= 1024 && i < 6) {

      b = b / 1024;

      i++;

    }

    if (i == 1) {

      printf "%d %s", b, u[i];

    } else {

      printf "%.2f %s", b, u[i];

    }

  }'

}

  local total_elapsed_sec="$1"

  local total_elapsed_fmt="$2"

  local file_post_total_sec="$3"

  local file_post_total_fmt="$4"

  local run_non_file_overhead_sec="$5"

  local run_non_file_overhead_fmt="$6"

  local avg_file_real_time_sec="$7"

  local avg_file_real_time_fmt="$8"

  local avg_video_time_sec="$9"

  local avg_video_time_fmt="${10}"

  local startup_warmup_fmt="${12}"

  local staging_warmup_sec="${13}"

  local staging_warmup_fmt="${14}"

  local input_bytes_processed="${15}"

  local output_bytes_processed="${16}"

  printf '\n'

  printf 'Run Summary\n'

  printf '+---------------------------+-------+\n'

  printf '| %-25s | %-5s |\n' "Metric" "Value"

  printf '+---------------------------+-------+\n'

  printf '| %-25s | %5s |\n' "Videos processed" "$VIDEOS_PROCESSED"

  printf '| %-25s | %5s |\n' "Videos skipped" "$VIDEOS_SKIPPED"

  printf '| %-25s | %5s |\n' "Invalid sources skipped" "$INVALID_SOURCES_SKIPPED"

  printf '| %-25s | %5s |\n' "Destination failures" "$DESTINATION_FAILURES"

  printf '| %-25s | %5s |\n' "Errors" "$ERRORS"

  printf '+---------------------------+-------+\n'

  printf '\nTimings\n'

  printf '+---------------------------+---------+----------+\n'

  printf '| %-25s | %-7s | %-8s |\n' "Metric" "Seconds" "Elapsed"

  printf '+---------------------------+---------+----------+\n'

  printf '| %-25s | %7s | %-8s |\n' "Total run time" "${total_elapsed_sec}s" "$total_elapsed_fmt"

  printf '| %-25s | %7s | %-8s |\n' "File wall time total" "${TOTAL_FILE_REAL_TIME_SEC}s" "$(format_seconds "$TOTAL_FILE_REAL_TIME_SEC")"

  printf '| %-25s | %7s | %-8s |\n' "Encode time total" "${TOTAL_VIDEO_TIME_SEC}s" "$(format_seconds "$TOTAL_VIDEO_TIME_SEC")"

  printf '| %-25s | %7s | %-8s |\n' "Post-processing total" "${file_post_total_sec}s" "$file_post_total_fmt"

  printf '| %-25s | %7s | %-8s |\n' "Non-file overhead" "${run_non_file_overhead_sec}s" "$run_non_file_overhead_fmt"

    printf '| %-25s | %7s | %-8s |\n' "Startup warm-up" "${startup_warmup_sec}s" "$startup_warmup_fmt"

  fi

  if [[ "$staging_warmup_sec" -ge 0 ]]; then

    printf '| %-25s | %7s | %-8s |\n' "Staging warm-up" "${staging_warmup_sec}s" "$staging_warmup_fmt"

  fi

  printf '+---------------------------+----------------+-----------------+\n'

  printf '| %-25s | %-14s | %-15s |\n' "Metric" "Bytes" "Human"

  printf '+---------------------------+----------------+-----------------+\n'

  printf '| %-25s | %14s | %-15s |\n' "Input processed" "${input_bytes_processed} B" "$(format_bytes_human "$input_bytes_processed")"

  printf '| %-25s | %14s | %-15s |\n' "Output written" "${output_bytes_processed} B" "$(format_bytes_human "$output_bytes_processed")"

  printf '+---------------------------+----------------+-----------------+\n'

  printf '+---------------------------+---------+----------+\n'

  printf '| %-25s | %-7s | %-8s |\n' "Metric" "Seconds" "Elapsed"

  printf '+---------------------------+---------+----------+\n'

  printf '| %-25s | %7s | %-8s |\n' "Average file wall time" "${avg_file_real_time_sec}s" "$avg_file_real_time_fmt"

  printf '| %-25s | %7s | %-8s |\n' "Average encode time" "${avg_video_time_sec}s" "$avg_video_time_fmt"

  printf '+---------------------------+---------+----------+\n'

}

  local temp_path

  local base_tmp="${TMPDIR:-/tmp}"

  base_tmp="${base_tmp%/}"

  temp_path="$(mktemp "$base_tmp/varia_ffmpeg.XXXXXX.log" 2>/dev/null || true)"

  if [[ -z "$temp_path" ]]; then

    temp_path="$(mktemp -t varia_ffmpeg 2>/dev/null || true)"

  fi

  printf '%s\n' "$temp_path"

}

  local target_file="$1"

  local target_dir target_base target_noext temp_path seed_path work_dir

  target_dir="$(dirname "$target_file")"

  target_base="$(basename "$target_file")"

  target_noext="${target_base%.*}"

  if [[ -n "$preferred_dir" ]]; then

    work_dir="$preferred_dir"

  fi

  seed_path="$(mktemp "$work_dir/.varia_tmp.${target_noext}.XXXXXX" 2>/dev/null || true)"

  if [[ -z "$seed_path" && "$work_dir" != "$target_dir" ]]; then

    seed_path="$(mktemp "$target_dir/.varia_tmp.${target_noext}.XXXXXX" 2>/dev/null || true)"

  fi

  if [[ -n "$seed_path" ]]; then

    rm -f -- "$seed_path" 2>/dev/null || true

    temp_path="${seed_path}.mp4"

  else

        temp_path="$target_dir/.varia_tmp.${target_noext}.$$.$RANDOM.mp4"

        if ! touch "$temp_path" >/dev/null 2>&1; then

          temp_path=""

        else

          rm -f -- "$temp_path" 2>/dev/null || true

        fi

      else

        temp_path=""

      fi

      rm -f -- "$temp_path" 2>/dev/null || true

    fi

  fi

  printf '%s\n' "$temp_path"

}

cleanup_transcode_artifacts() {

  local temp_output="$1"

  local final_output="$2"

  local exif_backup_alt="${temp_output}.exif_original"

  rm -f -- "$temp_output" 2>/dev/null || true

  # Defensive cleanup for previously failed non-atomic runs.

  if [[ -f "$final_output" && ! -s "$final_output" ]]; then

    rm -f -- "$final_output" 2>/dev/null || true

  fi

}

is_apple_noise_file() {

  local file_path="$1"

  local base

  base="$(basename "$file_path")"

  case "$base" in

    ._*|.DS_Store|.AppleDouble|._.DS_Store)

      return 0

      ;;

  esac

  return 1

}

  local flag="$1"

  local value="${2:-}"

  if [[ -z "$value" ]]; then

    die "Missing value for $flag"

  fi

}

to_abs_path() {

  local p="$1"

  if [[ "$p" = /* ]]; then

    printf '%s\n' "$p"

  else

    printf '%s\n' "$PWD/$p"

  fi

}

path_is_within() {

  local child="$1"

  local parent="$2"

  [[ "$child" == "$parent" || "$child" == "$parent"/* ]]

}

  local file_path="$1"

  local file_size="0"

  file_size="$(stat -f%z "$file_path" 2>/dev/null || true)"

  if [[ ! "$file_size" =~ ^[0-9]+$ ]]; then

    file_size="$(stat -c%s "$file_path" 2>/dev/null || true)"

  fi

  if [[ "$file_size" =~ ^[0-9]+$ ]]; then

    printf '%s\n' "$file_size"

  else

    printf '0\n'

  fi

}

dir_available_bytes_or_zero() {

  local dir_path="$1"

  local avail_kb=""

  avail_kb="$(df -Pk "$dir_path" 2>/dev/null | awk 'NR==2 {print $4}' || true)"

  if [[ "$avail_kb" =~ ^[0-9]+$ ]]; then

    printf '%s\n' $((avail_kb * 1024))

  else

    printf '0\n'

  fi

}

staging_has_space_for_input() {

  local staging_dir="$1"

  local input_file="$2"

  local input_size_bytes=0

  local needed_bytes=0

  local available_bytes=0

  [[ -n "$staging_dir" && -d "$staging_dir" && -w "$staging_dir" ]] || return 1

  input_size_bytes="$(file_size_bytes_or_zero "$input_file")"

  if [[ "$input_size_bytes" -le 0 ]]; then

    return 1

  fi

  # Keep one simple rule: need roughly 2x input size in staging.

  # This covers temp output plus metadata rewrite overhead.

  needed_bytes=$((input_size_bytes * 2))

  available_bytes="$(dir_available_bytes_or_zero "$staging_dir")"

  [[ "$available_bytes" -ge "$needed_bytes" ]]

}

  local out=""

  local arg

  for arg in "$@"; do

    out+="$(printf '%q' "$arg") "

  done

  printf '%s\n' "${out% }"

}

parse_args() {

  while [[ $# -gt 0 ]]; do

    case "$1" in

      -s|--source|--input)

        require_value "$1" "${2:-}"

        SOURCE_DIR="$2"

        SOURCE_PROVIDED=true

        shift 2

        ;;

      -d|--destination|--output)

        require_value "$1" "${2:-}"

        DEST_DIR="$2"

        DEST_PROVIDED=true

        shift 2

        ;;

        require_value "$1" "${2:-}"

        STAGING_DIR="$2"

        STAGING_PROVIDED=true

        shift 2

        ;;

        require_value "$1" "${2:-}"

        STAGING_RAMDISK_MB="$2"

        shift 2

        ;;

      --debug-timing)

        require_value "$1" "${2:-}"

        DEBUG_TIMING_LIMIT="$2"

        shift 2

        ;;

        require_value "$1" "${2:-}"

        MODE="$2"

        shift 2

        ;;

      --crf)

        require_value "$1" "${2:-}"

        CRF_OVERRIDE="$2"

        shift 2

        ;;

      --overwrite)

        OVERWRITE=true

        shift

        ;;

      --no-overwrite)

        OVERWRITE=false

        shift

        ;;

      --dry-run)

        DRY_RUN=true

        shift

        ;;

      --recursive)

        RECURSIVE=true

        shift

        ;;

      --no-recursive)

        RECURSIVE=false

        shift

        ;;

      --extensions)

        require_value "$1" "${2:-}"

        EXTENSIONS_CSV="$2"

        shift 2

        ;;

      --single)

        require_value "$1" "${2:-}"

        SINGLE_FILE="$2"

        shift 2

        ;;

      --verbose)

        VERBOSE=true

        shift

        ;;

        MOVE_SOURCE=true

        shift

        ;;

      --keep-going)

        FAIL_FAST=false

        shift

        ;;

      --unattended)

        MOVE_SOURCE=true

        FAIL_FAST=false

        shift

        ;;

      --no-apple-repack-fallback)

        APPLE_REPACK_FALLBACK=false

        shift

        ;;

      --apple-repack-fallback)

        APPLE_REPACK_FALLBACK=true

        shift

        ;;

        MOVE_SOURCE=true

        shift

        ;;

        FAIL_FAST=false

        shift

        ;;

        usage

        exit 0

        ;;

      *)

        die "Unknown argument: $1"

        ;;

    esac

  done

  case "$MODE" in

    auto|hardware|quality|compat) ;;

    *) die "Invalid --mode '$MODE'. Use auto|hardware|quality|compat." ;;

  esac

  if [[ "$SOURCE_PROVIDED" != true && "$DEST_PROVIDED" != true ]]; then

    die "At least one of --source or --destination must be provided"

  fi

  if [[ -n "$CRF_OVERRIDE" && ! "$CRF_OVERRIDE" =~ ^[0-9]+$ ]]; then

    die "--crf must be an integer"

  fi

  if [[ "$DEBUG_TIMING_LIMIT" != "0" ]]; then

    if ! [[ "$DEBUG_TIMING_LIMIT" =~ ^[0-9]+$ ]]; then

      die "--debug-timing must be a positive integer"

    fi

    if [[ "$DEBUG_TIMING_LIMIT" -le 0 ]]; then

      die "--debug-timing must be greater than 0"

    fi

  fi

  if ! [[ "$STAGING_RAMDISK_MB" =~ ^[0-9]+$ ]]; then

    die "--staging-ramdisk-mb must be a positive integer"

  fi

  if [[ "$STAGING_RAMDISK_MB" -le 0 ]]; then

    die "--staging-ramdisk-mb must be greater than 0"

  fi

check_tools() {

  command -v ffmpeg >/dev/null 2>&1 || die "ffmpeg not found in PATH"

  command -v ffprobe >/dev/null 2>&1 || die "ffprobe not found in PATH"

  HAS_AVCONVERT=false

  if [[ "$(uname -s)" == "Darwin" ]] && command -v avconvert >/dev/null 2>&1; then

    HAS_AVCONVERT=true

  fi

}

make_temp_repack_file() {

  local base_tmp="${TMPDIR:-/tmp}"

  local seed_path temp_path

  base_tmp="${base_tmp%/}"

  seed_path="$(mktemp "$base_tmp/varia_repack.XXXXXX" 2>/dev/null || true)"

  if [[ -n "$seed_path" ]]; then

    rm -f -- "$seed_path" 2>/dev/null || true

    temp_path="${seed_path}.mp4"

    printf '%s\n' "$temp_path"

    return

  fi

  temp_path="$base_tmp/varia_repack.$$.$RANDOM.mp4"

  printf '%s\n' "$temp_path"

}

cleanup_repacked_input() {

  local repacked_file="$1"

  if [[ -n "$repacked_file" ]]; then

    rm -f -- "$repacked_file" 2>/dev/null || true

  fi

}

try_apple_repack_for_unreadable() {

  local source_file="$1"

  local repacked_file=""

  REPACKED_SOURCE_PATH=""

  if [[ "$APPLE_REPACK_FALLBACK" != true || "$HAS_AVCONVERT" != true || "$(uname -s)" != "Darwin" ]]; then

    return 1

  fi

  repacked_file="$(make_temp_repack_file)"

  if [[ -z "$repacked_file" ]]; then

    return 1

  fi

  if [[ "$VERBOSE" == true ]]; then

    log_msg "WARN" "Trying avconvert passthrough repack fallback: $source_file"

    if ! avconvert --source "$source_file" --preset PresetPassthrough --output "$repacked_file" --replace; then

      cleanup_repacked_input "$repacked_file"

      return 1

    fi

  else

    if ! avconvert --source "$source_file" --preset PresetPassthrough --output "$repacked_file" --replace >/dev/null 2>&1; then

      cleanup_repacked_input "$repacked_file"

      return 1

    fi

  fi

  if ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$repacked_file" >/dev/null 2>&1; then

    REPACKED_SOURCE_PATH="$repacked_file"

    return 0

  fi

  cleanup_repacked_input "$repacked_file"

  return 1

restore_metadata_with_exiftool() {

  local input_file="$1"

  local output_file="$2"

  vlog_msg "CHECKPOINT" "metadata_start: $output_file"

  if [[ "$VERBOSE" == true ]]; then

    if exiftool -overwrite_original -m -TagsFromFile "$input_file" -all:all -unsafe "$output_file"; then

      vlog_msg "CHECKPOINT" "metadata_end: $output_file"

      return 0

    fi

  else

    if exiftool -overwrite_original -m -q -q -TagsFromFile "$input_file" -all:all -unsafe "$output_file" >/dev/null 2>&1; then

      vlog_msg "CHECKPOINT" "metadata_end: $output_file"

      return 0

    fi

  fi

    log_msg "INFO" "Metadata restore interrupted by user while stopping: $output_file"

    return 1

  fi

  return 1

}

map_garmin_model_to_standard_tags() {

  local input_file="$1"

  local output_file="$2"

  local garmin_model

  garmin_model="$(exiftool -s3 -UserData:GarminModel "$input_file" 2>/dev/null | head -n1 || true)"

  if [[ -z "$garmin_model" ]]; then

    vlog_msg "CHECKPOINT" "model_map_skip: no GarminModel in source: $input_file"

    return 0

  fi

  # used below because Garmin does not embed a parseable model string we can map.

  if [[ "$VERBOSE" == true ]]; then

    if exiftool -overwrite_original -m \

      -UserData:Make="Garmin" -UserData:Model="Varia RCT715" \

      -Keys:Make="Garmin" -Keys:Model="Varia RCT715" \

      -Keys:MajorBrand="isom" \

      -VideoKeys:LensModel="Fixed Wide Angle ${GARMIN_DECLARED_FOV_DEG} deg" \

      -VideoKeys:FocalLengthIn35mmFormat="$GARMIN_INFERRED_FOCAL_35MM_MM" \

      -XMP-exif:FocalLength="${GARMIN_INFERRED_FOCAL_MM} mm" \

      -XMP-exif:FocalLengthIn35mmFormat="$GARMIN_INFERRED_FOCAL_35MM_MM" \

      -XMP-exifEX:LensModel="Fixed Wide Angle ${GARMIN_DECLARED_FOV_DEG} deg" \

      "$output_file"; then

      vlog_msg "CHECKPOINT" "model_map_end: $output_file"

      return 0

    fi

  else

    if exiftool -overwrite_original -m -q -q \

      -UserData:Make="Garmin" -UserData:Model="Varia RCT715" \

      -Keys:Make="Garmin" -Keys:Model="Varia RCT715" \

      -Keys:MajorBrand="isom" \

      -VideoKeys:LensModel="Fixed Wide Angle ${GARMIN_DECLARED_FOV_DEG} deg" \

      -VideoKeys:FocalLengthIn35mmFormat="$GARMIN_INFERRED_FOCAL_35MM_MM" \

      -XMP-exif:FocalLength="${GARMIN_INFERRED_FOCAL_MM} mm" \

      -XMP-exif:FocalLengthIn35mmFormat="$GARMIN_INFERRED_FOCAL_35MM_MM" \

      -XMP-exifEX:LensModel="Fixed Wide Angle ${GARMIN_DECLARED_FOV_DEG} deg" \

      "$output_file" >/dev/null 2>&1; then

      vlog_msg "CHECKPOINT" "model_map_end: $output_file"

      return 0

    fi

  fi

  log_msg "ERROR" "Failed to map GarminModel to standard Make/Model tags: $output_file"

  return 1

}

write_transcode_encoder_metadata() {

  local output_file="$1"

  local encoder_meta

  encoder_meta="$TOOL_NAME mode=$ENCODER_KIND codec=$VIDEO_CODEC"

  vlog_msg "CHECKPOINT" "encoder_meta_start: $output_file ($encoder_meta)"

  if [[ "$VERBOSE" == true ]]; then

    if exiftool -overwrite_original -m \

      -Software="$encoder_meta" \

      -UserData:Software="$encoder_meta" \

      "$output_file"; then

      vlog_msg "CHECKPOINT" "encoder_meta_end: $output_file"

      return 0

    fi

  else

    if exiftool -overwrite_original -m -q -q \

      -Software="$encoder_meta" \

      -UserData:Software="$encoder_meta" \

      "$output_file" >/dev/null 2>&1; then

      vlog_msg "CHECKPOINT" "encoder_meta_end: $output_file"

      return 0

    fi

  fi

  log_msg "ERROR" "Failed to write encoder metadata: $output_file"

  return 1

detect_encoders() {

  local encoders

  encoders="$(ffmpeg -hide_banner -encoders 2>&1 || true)"

  if echo "$encoders" | grep -Eq '(^|[[:space:]])hevc_videotoolbox([[:space:]]|$)'; then

    HAS_VIDEOTOOLBOX=true

  fi

  if echo "$encoders" | grep -Eq '(^|[[:space:]])libx265([[:space:]]|$)'; then

    HAS_LIBX265=true

  fi

  if echo "$encoders" | grep -Eq '(^|[[:space:]])libx264([[:space:]]|$)'; then

    HAS_LIBX264=true

  fi

  if [[ "$VERBOSE" == true ]]; then

    log_msg "INFO" "Encoders: hevc_videotoolbox=$HAS_VIDEOTOOLBOX libx265=$HAS_LIBX265 libx264=$HAS_LIBX264"

  fi

}

resolve_encoder() {

  local os_name

  os_name="$(uname -s)"

  case "$MODE" in

    auto)

      if [[ "$os_name" == "Darwin" && "$HAS_VIDEOTOOLBOX" == true ]]; then

        ENCODER_KIND="hardware"

      elif [[ "$HAS_LIBX265" == true ]]; then

        ENCODER_KIND="quality"

      elif [[ "$HAS_LIBX264" == true ]]; then

        ENCODER_KIND="compat"

      else

        die "No suitable encoder found. Need one of hevc_videotoolbox, libx265, libx264."

      fi

      ;;

    hardware)

      [[ "$os_name" == "Darwin" ]] || die "--mode hardware is only supported on macOS (hevc_videotoolbox)"

      [[ "$HAS_VIDEOTOOLBOX" == true ]] || die "hevc_videotoolbox not available in ffmpeg"

      ENCODER_KIND="hardware"

      ;;

    quality)

      [[ "$HAS_LIBX265" == true ]] || die "libx265 not available in ffmpeg"

      ENCODER_KIND="quality"

      ;;

    compat)

      [[ "$HAS_LIBX264" == true ]] || die "libx264 not available in ffmpeg"

      ENCODER_KIND="compat"

      ;;

  esac

  case "$ENCODER_KIND" in

    hardware)

      VIDEO_CODEC="hevc_videotoolbox"

      VIDEO_CRF=""

      ;;

    quality)

      VIDEO_CODEC="libx265"

      VIDEO_CRF="${CRF_OVERRIDE:-$DEFAULT_CRF_HEVC}"

      ;;

    compat)

      VIDEO_CODEC="libx264"

      VIDEO_CRF="${CRF_OVERRIDE:-$DEFAULT_CRF_H264}"

      ;;

  esac

  vlog_msg "INFO" "Selected mode: $MODE (effective: $ENCODER_KIND, codec: $VIDEO_CODEC${VIDEO_CRF:+, crf: $VIDEO_CRF})"

}

probe_has_audio() {

  local input_file="$1"

  local out

  out="$(ffprobe -v error -select_streams a -show_entries stream=codec_type -of csv=p=0 "$input_file" || true)"

  [[ -n "$out" ]]

}

print_verbose_probe() {

  local input_file="$1"

  ffprobe -v error \

    -show_entries format=filename,format_name,duration,bit_rate,start_time:stream=index,codec_type,codec_name,profile,pix_fmt,width,height,avg_frame_rate,r_frame_rate,bit_rate \

    -of default=noprint_wrappers=1:nokey=0 "$input_file" || true

}

ffprobe_duration_or_empty() {

  local file_path="$1"

  ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$file_path" 2>/dev/null | head -n1

}

ffprobe_video_codec_or_empty() {

  local file_path="$1"

  ffprobe -v error -select_streams v:0 -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1 "$file_path" 2>/dev/null | head -n1

}

  local file_path="$1"

  REPACKED_SOURCE_PATH=""

  if ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$file_path" >/dev/null 2>&1; then

    SOURCE_READABLE_MODE="normal"

    return 0

  fi

  if [[ "$VERBOSE" == true ]]; then

    log_msg "WARN" "Source probe failed, trying tolerant mode: $file_path"

  fi

  if ffprobe -v error -fflags +genpts -err_detect ignore_err -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$file_path" >/dev/null 2>&1; then

    SOURCE_READABLE_MODE="tolerant"

    vlog_msg "INFO" "Source readable in tolerant mode: $file_path"

    return 0

  fi

  if try_apple_repack_for_unreadable "$file_path"; then

    SOURCE_READABLE_MODE="repacked"

    log_msg "WARN" "Using avconvert repack fallback for unreadable source: $file_path"

    return 0

  fi

  SOURCE_READABLE_MODE="normal"

  return 1

}

source_error_from_ffmpeg_log() {

  local ffmpeg_log="$1"

  [[ -n "$ffmpeg_log" && -f "$ffmpeg_log" ]] || return 1

  grep -Eiq 'invalid data found when processing input|error reading header|moov atom not found|corrupt|truncated|end of file|contradictionary STSC and STCO' "$ffmpeg_log"

}

destination_cannot_accept_file() {

  local input_file="$1"

  local out_dir="$2"

  local ffmpeg_log="$3"

  local probe_path=""

  local avail_kb=""

  local avail_bytes=0

  if [[ -n "$ffmpeg_log" && -f "$ffmpeg_log" ]]; then

    if grep -Eiq 'no space left on device|disk quota exceeded|read-only file system|permission denied|file too large|input/output error|stale file handle' "$ffmpeg_log"; then

      return 0

    fi

  fi

  probe_path="$(mktemp "$out_dir/.varia_write_probe.XXXXXX" 2>/dev/null || true)"

  if [[ -z "$probe_path" ]]; then

    return 0

  fi

  rm -f -- "$probe_path" 2>/dev/null || true

  avail_kb="$(df -Pk "$out_dir" 2>/dev/null | awk 'NR==2 {print $4}' || true)"

  if [[ "$avail_kb" =~ ^[0-9]+$ ]]; then

    avail_bytes=$((avail_kb * 1024))

    if [[ "$avail_bytes" -lt 67108864 ]]; then

      return 0

    fi

  fi

  return 1

}

  local input_file="$1"

  local output_file="$2"

  if [[ ! -f "$output_file" ]]; then

    log_msg "ERROR" "Validation failed: destination file missing: $output_file"

    return 1

  fi

  local expected_codec actual_codec

  case "$ENCODER_KIND" in

    hardware|quality) expected_codec="hevc" ;;

    compat) expected_codec="h264" ;;

    *)

      log_msg "ERROR" "Validation failed: unknown encoder kind '$ENCODER_KIND'"

      return 1

      ;;

  esac

  actual_codec="$(ffprobe_video_codec_or_empty "$output_file")"

  if [[ -z "$actual_codec" ]]; then

    log_msg "ERROR" "Validation failed: ffprobe could not read output codec: $output_file"

    return 1

  fi

  if [[ "$actual_codec" != "$expected_codec" ]]; then

    log_msg "ERROR" "Validation failed: codec mismatch for $output_file (expected=$expected_codec actual=$actual_codec)"

    return 1

  fi

  local in_duration out_duration duration_delta

  in_duration="$(ffprobe_duration_or_empty "$input_file")"

  out_duration="$(ffprobe_duration_or_empty "$output_file")"

  if [[ -z "$in_duration" || -z "$out_duration" ]]; then

    log_msg "ERROR" "Validation failed: missing duration probe data (input='$in_duration' output='$out_duration')"

    return 1

  fi

  duration_delta="$(awk -v a="$in_duration" -v b="$out_duration" 'BEGIN{d=a-b; if (d<0) d=-d; printf "%.3f", d}')"

  if ! awk -v d="$duration_delta" -v t="$DURATION_TOLERANCE_SEC" 'BEGIN{exit !(d<=t)}'; then

    log_msg "ERROR" "Validation failed: duration delta too large for $output_file (input=${in_duration}s output=${out_duration}s delta=${duration_delta}s tolerance=${DURATION_TOLERANCE_SEC}s)"

    return 1

  fi

  vlog_msg "INFO" "Validation OK: $output_file (codec=$actual_codec input_dur=${in_duration}s output_dur=${out_duration}s delta=${duration_delta}s)"

  return 0

}

build_video_args() {

  VIDEO_ARGS=()

  case "$ENCODER_KIND" in

    hardware)

      VIDEO_ARGS+=( -c:v "$VIDEO_CODEC" -b:v 8M -maxrate 16M -bufsize 24M -tag:v hvc1 )

      ;;

    quality)

      VIDEO_ARGS+=( -c:v "$VIDEO_CODEC" -crf "$VIDEO_CRF" -preset slow -tag:v hvc1 )

      ;;

    compat)

      VIDEO_ARGS+=( -c:v "$VIDEO_CODEC" -crf "$VIDEO_CRF" -preset slow -pix_fmt yuv420p )

      ;;

  esac

}

normalize_source_dir() {

  SOURCE_DIR="$(to_abs_path "$SOURCE_DIR")"

  [[ -d "$SOURCE_DIR" ]] || die "Source directory not found: $SOURCE_DIR"

  SOURCE_DIR="$(cd "$SOURCE_DIR" && pwd)"

}

normalize_dest_dir() {

  DEST_DIR="$(to_abs_path "$DEST_DIR")"

}

# AUTO_CREATED_STAGING_DEV, STAGING_RAMDISK_CREATED_AT

# Must be called directly (NOT inside $(...)) to preserve global assignments.

  local staging_path="$1"

  local ramdisk_name=""

  local sectors=0

  local dev=""

  local mount_point=""

  staging_path="${staging_path%/}"

  if [[ -d "$staging_path" ]]; then

  fi

  if [[ "$(uname -s)" != "Darwin" ]]; then

    return

  fi

  case "$staging_path" in

    /Volumes/*)

      ;;

    *)

      return

      ;;

  esac

  ramdisk_name="$(basename "$staging_path")"

  if [[ -z "$ramdisk_name" || "$ramdisk_name" == "." || "$ramdisk_name" == ".." ]]; then

    return

  fi

  if [[ "$staging_path" != "/Volumes/$ramdisk_name" ]]; then

    # Only auto-create for top-level /Volumes/<Name>, not nested paths.

    return

  fi

  [[ -x "/usr/bin/hdiutil" ]] || die "hdiutil not found; cannot auto-create RAM disk"

  [[ -x "/usr/sbin/diskutil" ]] || die "diskutil not found; cannot auto-create RAM disk"

  sectors=$((STAGING_RAMDISK_MB * 2048))

  vlog_msg "INFO" "Creating RAM disk for staging: /Volumes/$ramdisk_name (${STAGING_RAMDISK_MB}MB)"

  dev="$(/usr/bin/hdiutil attach -nomount "ram://$sectors" 2>/dev/null | /usr/bin/awk 'NR==1 {print $1}' || true)"

  if [[ -z "$dev" ]]; then

    return

  fi

  if ! /usr/sbin/diskutil eraseVolume APFS "$ramdisk_name" "$dev" >/dev/null 2>&1; then

    /usr/bin/hdiutil detach "$dev" >/dev/null 2>&1 || true

    return

  fi

  mount_point="$(/usr/sbin/diskutil info "$dev" 2>/dev/null | /usr/bin/awk -F': *' '/Mount Point/ {print $2; exit}')"

    mount_point="$staging_path"

    AUTO_CREATED_STAGING_DEV="$dev"

  fi

}

attempt_unmount_auto_staging_ramdisk() {

  if [[ "$AUTO_CREATED_STAGING_RAMDISK" != true || -z "$AUTO_CREATED_STAGING_PATH" ]]; then

    return

  fi

    return

  fi

  AUTO_STAGING_CLEANED_UP=true

    return

  fi

  if /usr/bin/hdiutil detach "$target" >/dev/null 2>&1; then

    return

  fi

  if [[ -d "$AUTO_CREATED_STAGING_PATH" ]]; then

    log_msg "WARN" "Could not unmount auto-created staging RAM disk; it remains mounted: $AUTO_CREATED_STAGING_PATH"

  else

}

  local rc=$?

  attempt_unmount_auto_staging_ramdisk

  return "$rc"

}

  if [[ "$STAGING_PROVIDED" != true ]]; then

    STAGING_DIR=""

    return

  fi

  STAGING_DIR="$(to_abs_path "$STAGING_DIR")"

    if [[ "$AUTO_CREATED_STAGING_RAMDISK" == true && -d "$AUTO_CREATED_STAGING_PATH" ]]; then

      STAGING_DIR="$AUTO_CREATED_STAGING_PATH"

    else

      die "Staging directory not found: $STAGING_DIR"

    fi

  fi

  STAGING_DIR="$(cd "$STAGING_DIR" && pwd)"

  [[ -w "$STAGING_DIR" ]] || die "Staging directory not writable: $STAGING_DIR"

  if path_is_within "$STAGING_DIR" "$SOURCE_DIR"; then

    die "Staging directory must not be inside source: staging=$STAGING_DIR source=$SOURCE_DIR"

  fi

}

  local raw="$EXTENSIONS_CSV"

  local token

  EXT_LIST=()

  IFS=',' read -r -a tokens <<< "$raw"

  for token in "${tokens[@]}"; do

    token="$(printf '%s' "$token" | sed -E 's/^[[:space:]]+//; s/[[:space:]]+$//')"

    token="${token#.}"

    token="$(printf '%s' "$token" | tr '[:upper:]' '[:lower:]')"

    [[ -n "$token" ]] && EXT_LIST+=("$token")

  done

  if [[ ${#EXT_LIST[@]} -eq 0 ]]; then

    die "No valid extensions after parsing --extensions"

  fi

}

build_find_expr_for_extensions() {

  FIND_EXT_EXPR=()

  local ext

  for ext in "${EXT_LIST[@]}"; do

    FIND_EXT_EXPR+=( -iname "*.${ext}" -o )

  done

  if [[ ${#FIND_EXT_EXPR[@]} -gt 0 ]]; then

    unset 'FIND_EXT_EXPR[${#FIND_EXT_EXPR[@]}-1]'

  fi

}

rel_path_from_source() {

  local abs_file="$1"

  if path_is_within "$abs_file" "$SOURCE_DIR"; then

    printf '%s\n' "${abs_file#$SOURCE_DIR/}"

  else

    printf '%s\n' "$(basename "$abs_file")"

  fi

}

collect_video_files() {

  VIDEO_FILES=()

  if [[ -n "$SINGLE_FILE" ]]; then

    local single_abs

    single_abs="$(to_abs_path "$SINGLE_FILE")"

    [[ -f "$single_abs" ]] || die "--single file not found: $single_abs"

    VIDEO_FILES+=("$single_abs")

    return

  fi

  build_find_expr_for_extensions

  while IFS= read -r -d '' file; do

      vlog_msg "SKIP" "Ignoring Apple artifact: $file"

      continue

    fi

  done < <(

    if [[ "$RECURSIVE" == true ]]; then

      find "$SOURCE_DIR" \

        -path "$DEST_DIR" -prune -o \

        -type f \( "${FIND_EXT_EXPR[@]}" \) -print0

    else

      find "$SOURCE_DIR" \

        -maxdepth 1 -type f \( "${FIND_EXT_EXPR[@]}" \) -print0

    fi

  )

}

process_video_file() {

  local input_file="$1"

  local display_path

  local encode_input_file

  local encode_started_at encode_ended_at encode_elapsed_sec=0

  local post_elapsed_sec

  file_started_at="$(date +%s)"

  vlog_msg "CHECKPOINT" "file_start: $input_file"

  rel_path="$(rel_path_from_source "$input_file")"

  output_file="$DEST_DIR/${rel_path%.*}.mp4"

  out_dir="$(dirname "$output_file")"

  encode_input_file="$input_file"

  mkdir -p "$out_dir"

    ERRORS=$((ERRORS + 1))

    INVALID_SOURCES_SKIPPED=$((INVALID_SOURCES_SKIPPED + 1))

    if [[ "$VERBOSE" == true ]]; then

      log_msg "ERROR" "Skipping unreadable/corrupted source video: $input_file"

    else

      log_progress_start "$display_path"

      log_progress_skipped_unreadable "$display_path"

    fi

    return 2

  fi

  if [[ "$SOURCE_READABLE_MODE" == "repacked" && -n "$REPACKED_SOURCE_PATH" ]]; then

    repacked_input_file="$REPACKED_SOURCE_PATH"

    encode_input_file="$REPACKED_SOURCE_PATH"

    vlog_msg "INFO" "Encoding from avconvert repacked source: $repacked_input_file"

  fi

    vlog_msg "SKIP" "Video exists: $output_file"

    VIDEOS_SKIPPED=$((VIDEOS_SKIPPED + 1))

  fi