VariaReEncoder

Batch transcoder for Garmin Varia dashcam footage. Converts H.264 source clips to HEVC MP4, optimized for Apple Photos / QuickTime compatibility.

Requirements

• macOS or Linux
• ffmpeg and ffprobe in PATH (any recent version with libx265/libx264; videotoolbox on macOS)
• Bash 3.2+

Quick Start

# Transcode everything in SampleFootage → Output (hardware encoder on macOS)
./garmin_varia_transcode.sh -s SampleFootage -d Output

# Preview what would happen without writing any files
./garmin_varia_transcode.sh -s SampleFootage -d Output --dry-run

# Single file, verbose output
./garmin_varia_transcode.sh -s SampleFootage/Day/clip.mp4 -d Output --verbose

# Transcode + delete originals after validation
./garmin_varia_transcode.sh -s SampleFootage -d Output --delete-source

# Long unattended run preset (delete-source + keep-going; also stages input when --staging-dir is set)
./garmin_varia_transcode.sh -s SampleFootage -d Output --unattended

# NFS destination with local staging for temp outputs
./garmin_varia_transcode.sh -s SampleFootage -d ~/Autofs/xdev/is-baobab/nvme0n1/@backup/Garmin --staging-dir /tmp/varia_staging

# Flaky NAS/autofs source: copy each source clip to local staging before encode
./garmin_varia_transcode.sh -s ~/Autofs/xdev/autonas/ext01/@Camera/import -d ~/Autofs/xdev/autonas/ext00/@Garmin --unattended --staging-dir /Volumes/VARIA_RAM --staging-ramdisk-mb 512 --stage-input

# Timing debug: process first 20 files then stop and print final statistics
./garmin_varia_transcode.sh -s SampleFootage -d Output --debug-timing 20

# Media cleanup helper (Apple artifacts, zero-byte MP4, duplicate suffix normalization)
./cleanup_garmin_varia_media_folder.sh --dry-run ~/Autofs/xdev/autonas/ext01/@Camera/import

Encoding Modes

* Measured on Apple Silicon MacBook Pro.

CLI Reference

Options:
  -s, --source, --input DIR       Source directory or single file (default: current directory)
  -d, --destination, --output DIR Destination directory (default: current directory)
  --staging-dir DIR               Temporary staging directory for intermediate output files
                                  Falls back to destination temp files if staging is unavailable
                                  or does not have enough free space for current file
  --stage-input                   Copy each source video to staging before encoding; useful
                                  for flaky NAS/autofs source reads
  --staging-ramdisk-mb N          RAM disk size in MB when auto-creating missing /Volumes staging
                                  directory on macOS (default: 8192)
  --debug-timing N                Process at most N video files, then stop and print timing stats
  --mode MODE                     hardware|auto|quality|compat (default: hardware)
  --crf N                         CRF for quality/compat modes (lower = better; default: 20/19)
  --no-overwrite                  Skip files that already exist at destination
  --dry-run                       Print actions without writing files
  --no-recursive                  Process only the top-level source directory
  --extensions LIST               Comma-separated extensions (default: mp4,mov,avi,m4v)
  --verbose                       Full per-operation logs + ffmpeg/ffprobe output
  --delete-source                 Delete source after strict post-encode validation
  --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)
  -h, --help                      Show full help with encoding mode details

Output Conventions

• Output is always .mp4
• HEVC outputs tagged hvc1 (required for Apple Photos / QuickTime)
• Directory structure under source is preserved at destination
• File timestamps copied from source (touch -r)

Output Format (quiet mode, default)

2026-05-04 12:08:00 : Transcoding SampleFootage/Day/2026-04-04_18-10-36.mp4 ... done in 5s
2026-05-04 12:08:04 : Transcoding SampleFootage/Day/2026-04-04_18-10-05.mp4 ... done in 4s
[2026-05-04 12:08:35] [INFO] Summary: videos_processed=10 videos_skipped=0 errors=0
[2026-05-04 12:08:35] [INFO] Timing: total_elapsed=44s, video_encode_avg=4s

Safety

• Destination inside source is rejected with an error
• Source readability and destination writability are checked before staging or scanning, so stale/inaccessible NFS/autofs mounts fail with an explicit error
• --delete-source only deletes source after codec + duration validation passes
• --dry-run never writes files
• Ctrl+C behavior during long runs: first press requests stop after current file; second press force-stops current encode
• Graceful quit between files: press q (or Q) during interactive runs to request a graceful stop before the next file begins. --unattended disables q/Q terminal polling so buffered terminal input cannot stop long runs accidentally; use Ctrl+C.
• On macOS, unreadable MP4/MOV sources automatically try avconvert --preset PresetPassthrough as fallback before being marked as unreadable

Backward-compatible aliases: - --move-source maps to --delete-source - --continue-on-error maps to --keep-going

Media Cleanup Utility

cleanup_garmin_varia_media_folder.sh is a companion utility for import and transcoded media folders.

What it does: - Removes AppleDouble artifacts (._*) up to 4096 bytes - Removes zero-size .mp4 files - Normalizes duplicate timestamp files: if YYYY-MM-DD_HH-MM-SS.mp4 is missing and exactly one YYYY-MM-DD_HH-MM-SS_<n>.mp4 exists, it renames it to base name - Reports blocked duplicate groups when base exists or multiple suffixed duplicates exist

Usage:

# Preview only
./cleanup_garmin_varia_media_folder.sh --dry-run ~/Autofs/xdev/autonas/ext01/@Camera/import

# Apply changes
./cleanup_garmin_varia_media_folder.sh ~/Autofs/xdev/autonas/ext01/@Camera/import

# Example on transcoded output folder
./cleanup_garmin_varia_media_folder.sh --dry-run ~/Autofs/xdev/is-baobab/nvme0n1/@backup/Garmin

Exit codes: - 0: cleanup completed with no blocked duplicate groups - 1: cleanup completed but blocked duplicate groups require manual review - 2: invalid invocation or runtime error

Source Files

SampleFootage/          Original clips (gitignored)
Output/                 Transcoded output (gitignored)
garmin_varia_transcode.sh   Main script
cleanup_garmin_varia_media_folder.sh   Media cleanup utility (import + transcoded folders)
CHANGELOG.md            Version history
DEVLOG.md               Development decisions and rationale