# VariaReEncoder

Batch transcoder for Garmin Varia dashcam footage. Converts H.264 source clips to HEVC MP4,
optimized for Apple Photos / QuickTime compatibility, with sidecar JSON copy and a telemetry
manifest placeholder for a future FIT sync pipeline.

## Requirements

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

## Quick Start

```bash
# 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 --move-source
```

## Encoding Modes

| Mode       | Encoder            | Speed (30s clip) | Power\*   | Use when |
|------------|--------------------|-----------------|-----------|----------|
| `hardware` | hevc_videotoolbox  | ~4-5s           | ~35W      | Default — battery, large libraries, dashcam footage |
| `auto`     | videotoolbox → x265 → x264 | varies | varies   | Cross-platform or unknown machine |
| `quality`  | libx265 (CRF 20)   | ~50s            | ~80W      | Archival, cinema, complex sources |
| `compat`   | libx264 (CRF 19)   | ~30s            | ~70W      | Older TVs, players without HEVC support |

\* 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)
  --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
  --move-source                   Delete source after strict post-encode validation
  -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`)
- JSON sidecars copied 1:1 to destination
- `telemetry_manifest.json` written to destination as a placeholder for a future FIT sync pipeline

## 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
- `--move-source` only deletes source after codec + duration validation passes
- `--dry-run` never writes files

## Source Files

```
SampleFootage/          Original clips (gitignored)
Output/                 Transcoded output (gitignored)
garmin_varia_transcode.sh   Main script
CHANGELOG.md            Version history
DEVLOG.md               Development decisions and rationale
```