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Welcome to the vapoursynth-zipcl wiki!

vszipcl is a VapourSynth plugin written in Zig that provides OpenCL-accelerated video filters. Every filter shares one architecture (a shared cl_context, a prewarmed per-stream resource pool, and a num_streams knob that actually scales), and each is a faithful port of an established reference — verified bit-exact where the reference allows.

All filters accept 8/16-bit integer, 16-bit half, and 32-bit float input (except where noted) and are multi-plane (Gray / YUV / RGB, subsampled chroma).

FILTERS

• Bilateral: OpenCL port of VapourSynth-BilateralGPU — bit-exact on integer input.
• Deband: OpenCL port of placebo.Deband (libplacebo's pl_shader_deband).
• EEDI3 / EEDI3H: Edge-directed interpolation (vertical / horizontal), same numeric core as the vapoursynth-zip CPU EEDI3.
• GaussBlur: Separable Gaussian blur.
• NLMeans: Non-local means denoiser, matching KNLMeansCL.

📊 See Benchmarks — vszipcl vs each reference at 1080p YUV420 (u16/f16/f32, num_streams 1 & 2).

COMMON ARGUMENTS

Every filter takes these two optional arguments:

• device_id (int, default: 0):
  OpenCL device index (platform 0). Out-of-range or negative values are rejected.
• num_streams (int, default: 1, range: 1..32):
  Number of concurrent per-frame resource sets. The default of 1 serializes to one frame at a time; raise it to overlap more frames on the GPU (up to what the kernel/transfer mix can hide — 2 already captures most of the scaling). Output is bit-identical at any stream count.

BENCHMARK

RTX 3070 Ti, 1080p, decode-inclusive (bs.VideoSource), 300 frames. vszipcl wire-format support (u8/u16/f16) halves or quarters the PCIe transfer vs f32, so integer clips are often the fastest path.

# Bilateral (YUV420P8) — bit-exact vs bilateralgpu, ~1.75x faster (on-device convert, 1 byte/sample)
src.vszipcl.Bilateral()          #  ~405 fps
src.bilateralgpu.Bilateral()     #  ~231 fps

# NLMeans (YUV420P8, channels="Y", d=1, s=4)
src.vszipcl.NLMeans(channels="Y", d=1, s=4)   # u8 ~173 fps | f32 ~133 fps
src.knlm.KNLMeansCL(channels="Y", d=1, s=4)   # u8  ~80 fps

# Deband / GaussBlur (GRAY, transfer-bound — u8 ~2x f32)
src.vszipcl.Deband()      # u8 ~880 fps | f16 ~600 | f32 ~383
src.vszipcl.GaussBlur()   # u8 ~800 fps | f16 ~575 | f32 ~380