### Honest codec measurements (vs ffmpeg reference, full Kodak/Tecnick/
CLIC/synthetic corpus = 169 images, plus SQAM audio + Silesia text + Derf CIF video)

| codec | runs | size vs ref | PSNR Δ vs ref | notes |
|---|---:|---:|---:|---|
| PNG | 169 | — | lossless | ffmpeg-interop ok |
| JPEG q=50 | 169 | +12.7% | +0.27 dB | q-knob calibrated to libjpeg |
| JPEG q=80 | 169 | +19.7% | −0.31 dB | residual gap is pure-Rust vs libjpeg-turbo asm |
| AVIF q=70 | 169 | — | — | ffmpeg-interop ok |
| JPEG-XL lossless | 169 | — | lossless | bit-exact via libjxl |
| FLAC | 5 | **−10.1%** | lossless | WAI compression_level 8 vs ffmpeg default 5 |
| Opus 64k | 5 | — | — | standard Ogg-Opus container, ffmpeg-interop ok |
| zstd-19 | 13 | ±0.0% | — | **byte-identical to system zstd** |
| xz-6 | 13 | ±0.0% | — | **byte-identical to system xz** |
| AV1 lossy | 12 | +28.3% | — | rav1e vs ffmpeg libsvtav1 (different encoders) |

All 588 corpus runs and all 44 tests pass.

