# GPU lane: CUDA + bf16 across all three models. Full pipeline (BiRefNet seg +
# ViTMatte + HR-matting cross-check). Foreground estimation auto-uses the CuPy GPU
# backend when cupy is installed (see foreground.use_gpu, default on). despill is
# off (it false-positives on subjects sharing the background hue).
screen_color: null

chroma:
  # true = flat-colour background (default). false = non-flat/complex background
  # mode: no colour key; segmentation alone drives the trimap (mode forced to
  # "seg") and the colour-keyed stages are bypassed (auto-detect, hue split,
  # chroma suppression, despill). The cross-check veto still runs if enabled,
  # using its hue-free gate (cross_check.second_lo/hi). The service selects this
  # per request via background_mode=flat|complex; this is only the base default.
  enabled: true

model:
  model_name: hustvl/vitmatte-base-composition-1k
  device: cuda
  matting_method: vitmatte
  fallback_to_chroma_alpha: false
  precision: bf16
  attn_query_chunk: 2048

segmentation:
  enabled: true
  backend: birefnet
  model_name: ZhengPeng7/BiRefNet
  device: cuda
  input_size: 1024
  precision: bf16

trimap:
  sure_bg_threshold: 0.92
  sure_fg_threshold: 0.12
  unknown_radius_ratio: 0.012
  fg_safe_radius_ratio: 0.006
  seg_core_threshold: 0.60
  seg_loose_threshold: 0.08
  mode: directional
  seg_low: 0.15
  bg_hue_proj_min: 4.0
  seg_force_fg: 0.98

alpha_post:
  chroma_suppress: true
  chroma_suppress_bg_low: 0.35
  chroma_suppress_bg_high: 0.80
  chroma_suppress_strength: 1.0
  suppress_raw_lo: 0.85
  suppress_raw_hi: 0.98

cross_check:
  enabled: true
  model_name: ZhengPeng7/BiRefNet_HR-matting
  input_size: 2048
  reuse_as_seg: false
  precision: bf16
  proj_min: 3.0
  l_min: 45.0
  feather_sigma: 2.0
  gate_lo: 0.70
  gate_hi: 0.95
  # Complex-background (non-flat) mode only: no hue-defined suspect zone, so the
  # veto requires the second opinion itself to be confidently near-empty -- full
  # strength at/below second_lo, fading to none at/above second_hi.
  second_lo: 0.15
  second_hi: 0.40

foreground:
  enabled: true
  method: ml
  ml_regularization: 0.00001

despill:
  enabled: false

server:
  # Request concurrency (HTTP service only). cpu_workers = thread-pool size: >1 runs
  # several requests at once, overlapping their CPU stages while the GPU forwards
  # stay serialized -- keeps the GPU fed. gpu_concurrency = how many forwards may
  # co-schedule on the SMs at once: 2 lifts GPU-bound throughput (batch-1 underfills
  # the SMs) but roughly DOUBLES GPU activation memory.
  #   * On a >=24 GB card (e.g. 4080 SUPER 32 GB): gpu_concurrency: 2 peaks ~19 GB.
  #   * On a <=16 GB card: keep gpu_concurrency: 1 or it will OOM at 2048 cross-check.
  # Env vars BGFILTER_CPU_WORKERS / BGFILTER_GPU_CONCURRENCY override these per box.
  cpu_workers: 8
  gpu_concurrency: 2