Hardware Acceleration
Alchemist detects hardware automatically at startup, actively probes every plausible backend/codec candidate, and selects a single active device/backend with a deterministic scoring policy. Override in Settings → Hardware.
Detection flow (auto mode)
- Discover plausible candidates
- Apple VideoToolbox on macOS
- NVIDIA NVENC when NVIDIA is present
- Intel / AMD render nodes on Linux via
/sys/class/drm/renderD* - AMD AMF on Windows
- Actively probe every candidate encoder with a short FFmpeg test encode
- Group successful probes by device path / vendor
- Choose one active device/backend using codec coverage, backend preference, and stable vendor ordering
- Fall back to CPU only if no GPU probe succeeds and CPU fallback is enabled
Encoder support by vendor
| Vendor | AV1 | HEVC | H.264 | Notes |
|---|---|---|---|---|
| NVIDIA NVENC | RTX 30/40 | Maxwell+ | All | Best for speed |
| Intel QSV | 12th gen+ | 6th gen+ | All | Best for power efficiency |
| AMD VAAPI/AMF | RDNA 2+ on compatible driver/FFmpeg stacks | Polaris+ | All | Linux VAAPI / Windows AMF; HEVC/H.264 are the validated AMD paths for 0.3.0 |
| Apple VideoToolbox | M3+ | M1+/T2 | All | Binary install recommended |
| CPU | All | All | All | Always available |
Hardware probe
Alchemist probes each encoder at startup with a test encode
using a standardized 256x256 lavfi input.
See results in Settings → Hardware → Probe Log. The UI shows:
- the selected device/backend reason
- probe counts (attempted / succeeded / failed)
- per-probe summaries for success and failure
- full FFmpeg stderr for failed probes
On Linux, explicit device paths only apply to render-node backends such as VAAPI and QSV.