# OpenTranscode

A single-file, batch transcoding GUI for Linux built with PySide6. Wraps **av1an** for chunk-parallel AV1/VP9/x265 encoding with a retro-futuristic MMD3 media console aesthetic.

![Python 3.12+](https://img.shields.io/badge/Python-3.12%2B-blue)
![PySide6](https://img.shields.io/badge/PySide6-6.6%2B-green)
![Linux](https://img.shields.io/badge/Platform-Linux-orange)
![License: AGPL-3.0](https://img.shields.io/badge/License-AGPL--3.0-yellow)

![OpenTranscode](/home/dcosnet/Desktop/projects-preped/OpenTranscode/OpenTranscode.png)



## Features

- **Batch encoding** — Drop a source folder, pick settings, hit encode. Processes every matching file recursively.
- **Three open codecs** — AV1 (SVT-AV1), VP9 (libvpx), x265 (HEVC) with per-codec preset selection.
- **Config-driven profiles** — Codecs, audio, containers, and resolutions defined as dataclass tables — no nested if/else chains.
- **av1an chunk-parallel encoding** — Scene-based chunking with multi-worker parallelism. Automatically detects `--chunk-method` support and scales workers to physical CPU cores minus one.
- **Lossless intermediate pipeline** — Resolution changes use a lossless libx264 ultrafast CRF 0 pre-scale pass (yuv420p10le) with duration integrity verification before the final encode.
- **Forced subtitle muxing** — Optional soft-subtitle remux post-encode. Prefers forced-disposition tracks. Container-aware: WebVTT for WebM, stream copy for MKV.
- **Audio normalization** — Rotary volume knob (-20 dB to +6 dB gain).
- **Real-time FFmpeg library probing** — Greys out audio codecs whose underlying FFmpeg libraries are missing.
- **Distro-aware dependency management** — Auto-detects Arch, Debian/Ubuntu, Fedora/RHEL/Rocky/Alma, openSUSE, and NixOS. Installs packages, handles av1an version conflicts, and builds from source when repos are stale.
- **Post-encode integrity checks** — Verifies output file size (≥ 5% of source) and duration (≥ 95% of source) before accepting. Failed outputs are deleted automatically.
- **Batch delete with confirmation** — Single pre-flight prompt showing file count and total size. Sources deleted only after individual verification passes.
- **Custom radio-knob widgets** — Retro rotary controls for CRF and audio normalization with snap-to-tick, glow indicators, and mouse/scroll interaction.
- **MMD3 theme** — Brushed aluminum, amber/green LED displays, beveled metallic panels via QSS.

## Requirements

| Dependency | Minimum Version | Purpose |
|---|---|---|
| Python | 3.12+ | Runtime |
| PySide6 | 6.6+ | Qt6 GUI framework |
| av1an | 0.4.0+ | Chunk-parallel encoder frontend |
| FFmpeg | 5.0+ (with libsvtav1, libvpx, libx265, libopus, libvorbis, flac) | Encoding, probing, remuxing |
| ffprobe | (bundled with FFmpeg) | Stream analysis and validation |
| mkvtoolnix | any | MKV container support |
| Rust/Cargo | latest stable | Building av1an from source (if repo version is stale) |

### Per-Distro Package Lists

**Arch / Manjaro / Endeavouros / Garuda / CachyOS:**
`ffmpeg mkvtoolnix-cli nasm cython gcc cmake git ninja python-pip svt-av1 rav1e aom libvpx x265 libopus libvorbis flac`

**Debian / Ubuntu / Linux Mint / Pop!_OS:**
`ffmpeg av1an mkvtoolnix svt-av1 rav1e aom-tools libvpx-tools x265 nasm gcc cmake git cargo rustc`

**Fedora:**
`ffmpeg mkvtoolnix svt-av1 rav1e aom libvpx x265 nasm gcc cmake git ninja-build cargo rustc` (requires RPM Fusion)

**RHEL / CentOS / Rocky / Alma:**
Same as Fedora, plus `epel-release` and RPM Fusion.

**openSUSE (Tumbleweed/Leap):**
`ffmpeg av1an mkvtoolnix svt-av1 rav1e aom-tools libvpx-tools x265 nasm gcc cmake git ninja cargo rustc` (requires Packman repo)

**NixOS:**
Manual configuration required — see quickstart.

> All distros: if the packaged av1an is below 0.4.0, the app automatically builds from git.

## Install & Run

```bash
# Clone the repo
git clone https://github.com/YOUR_USER/open-transcode.git
cd open-transcode

# Install Python dependency
pip install PySide6

# Run — dependency auto-install triggers on first launch
python open-transcode-master.py
```

On first launch, if av1an or FFmpeg is missing, the app detects your distro and offers to install everything automatically (Arch, Debian, Fedora, openSUSE). NixOS users will see a config snippet to paste into their configuration.

## Project Structure

```
open-transcode/
├── open-transcode-master.py   # Single-file application (~2800 lines)
├── README.md                  # This file
├── quickstart.md              # Setup & first-encode walkthrough
├── LICENSE                    # AGPL-3.0
└── .gitignore                 # Python/Qt/OS artifacts
```

## How It Works

### Encoding Pipeline

```
Source file
  │
  ├─ ffprobe pre-validation (skip if no video stream or < 0.5s)
  │
  ├─ [If resolution != Original]
  │   └─ Lossless pre-scale → {file}.scaled_tmp.mkv
  │       (libx264 ultrafast CRF 0, yuv420p10le, scale+pad filter)
  │       └─ Duration integrity check (≥ 95% of source)
  │
  ├─ av1an encode (chunk-parallel, scene-based splitting)
  │   └─ Workers: physical_cores - 1
  │
  ├─ Post-encode verification
  │   ├─ Size check: output ≥ 5% of source
  │   └─ Duration check: output ≥ 95% of source
  │
  ├─ [If subtitle language selected]
  │   └─ Soft subtitle remux (forced track preferred)
  │       ├─ MKV: -c:s copy (any codec)
  │       └─ WebM: -c:s webvtt (container requirement)
  │
  └─ [If delete-source enabled]
      └─ Delete source (only after verification passes)
```

### Distro Auto-Detection

On startup, reads `/etc/os-release` and matches against known distro families. Each family has:
- Package manager and install command template
- Extra binary search paths (e.g. `~/.cargo/bin` for Rust-built tools)
- Distro-specific av1an encoder name quirks
- A dedicated `*_prep_deps()` function with fine-grained package installation

### Config-Driven Profiles

All codec/container/audio/resolution options are defined as `@dataclass` tables:

- `VIDEO_CODECS` — Label, av1an encoder name, CRF range, default CRF, params function, preset map
- `AUDIO_PROFILES` — Label + FFmpeg parameter tokens
- `CONTAINER_PROFILES` — Label + file extension
- `RESOLUTION_PRESETS` — Label, category (standard/wide/ultrawide/original), dimensions
- `SUBTITLE_OPTIONS` — Label + ISO 639-2 language code (or None)

The UI indexes into these tables — zero conditional logic for profile selection.

## Supported Input Formats

Default: `.mp4 .mkv .avi .mov .ts .m4v .flv .wmv .webm .mpg .mpeg`

Configurable at runtime via the FILTER field in the UI (comma-separated extensions).

## Supported Output Formats

| Container | Video Codecs | Audio Codecs | Subtitles |
|---|---|---|---|
| MKV (.mkv) | AV1, VP9, x265 | Opus, Vorbis, FLAC | Any (stream copy) |
| WebM (.webm) | AV1, VP9 | Opus, Vorbis, FLAC | WebVTT only |

## UI Controls

| Control | Type | Range / Options |
|---|---|---|
| SOURCE / SINK | Path fields + browse | Any directory |
| VIDEO | Combo | AV1 (SVT-AV1), VP9, x265 (HEVC) |
| PRESET | Combo | 4 per codec (e.g. Slow/Medium/Fast/Faster) |
| AUDIO | Combo | Opus 96k/128k/64k, Vorbis 128k/192k, FLAC |
| CONTAINER | Combo | MKV, WebM |
| RESOLUTION | Combo | Original, 720p–4K (16:9 / 21:9 / 32:9) |
| SUBS | Combo | None, English (forced track preferred) |
| CRF | Rotary knob | 18–52 (codec-dependent range) |
| AUDIO NORM | Rotary knob | -20 dB to +6 dB (0 = off) |
| DELETE SOURCE | Checkbox | Per-batch confirmation prompt |

## Troubleshooting

**av1an build fails:** Ensure Rust is installed (`rustup`) and you have ~2 GB of free disk space in `/tmp`. The build takes 5–15 minutes depending on hardware.

**Codec greyed out:** The corresponding FFmpeg library is missing. Install it via your package manager or re-run the auto-prep.

**"chunk-method not recognized":** Your av1an is below 0.4.0. The auto-prep should handle this by building from git. If it doesn't, manually remove the packaged av1an and rebuild.

**WebM + non-WebVTT subtitles fail:** WebM only supports WebVTT subtitles. The app auto-converts during remux. If the source subtitle codec can't be converted, the mux is silently skipped.

**Permission denied on av1an install:** The git build attempts `sudo cp` to `/usr/local/bin`. Ensure your user has sudo access, or manually copy the binary from `/tmp/av1an-build/target/release/av1an`.

## License

AGPL-3.0 — see [LICENSE](LICENSE).