pydecklink

Python bindings for the Blackmagic DeckLink SDK, exposing the capture and scheduled playback APIs via CPU buffers (numpy), and the network surface of the DeckLink IP cards that carry SMPTE ST 2110.

Requirements

• Linux, macOS, or Windows with Blackmagic Desktop Video 16.0 or later installed — the binding is built against the 16.0 SDK headers, whose interfaces an older runtime does not serve
• Blackmagic DeckLink hardware
• Python 3.12+

Install

uv pip install pydecklink

Prebuilt wheels ship for Linux (manylinux x86_64), macOS, and Windows. Building from source requires a C++ toolchain — see CONTRIBUTING.md.

Usage

import pydecklink

# Desktop Video runtime version
print(pydecklink.api_version().string)

# Enumerate DeckLink devices
for info in pydecklink.list_devices():
    print(f"{info.index}: {info.model_name}")

# Display modes a device can output
dev = pydecklink.Device(0)
for m in dev.list_output_modes():
    fps = pydecklink.get_mode_fps(m.mode)
    print(f"{m.name}: {m.width}x{m.height} @ {fps:.2f}")

Examples

The examples/ directory in the repo contains runnable scripts:

CUDA examples need the cuda-examples extra (uv pip install "pydecklink[cuda-examples]").

API

The package ships type stubs (pydecklink/_bindings.pyi) and a py.typed marker, so editors and mypy see the full typed surface. Key entry points:

Device discovery

• list_devices() -> list[DeviceInfo], device_count() -> int
• api_version() -> APIVersion — Desktop Video runtime version
• connector_label(device) -> str | None — physical SDI port label

Display-mode helpers

• get_mode_width(mode), get_mode_height(mode), get_mode_fps(mode)
• get_mode_frame_duration(mode), get_frame_bytes(mode, pixel_format), get_row_bytes(pixel_format, width)

Device — open a card with Device(index), then:

• Capture: enable_video_input(...), start_streams(), and pop_capture_frame() (copying) or pop_capture_frame_ref() (zero-copy).
• Scheduled playback: enable_video_output(...), create_frame_pool(...), acquire_output_frame(), schedule_output_frame(...), start_scheduled_playback(...).
• Zero-copy passthrough: schedule_capture_frame(...) forwards a captured frame straight to output with no memcpy.

DeckLink IP — the card runs its own IP stack, so the host has no network device for its media port and the address is set through the SDK or not at all. Each Ethernet connector has its own address: ConfigurationID.ConfigParamEthernet* covers a connector's address, subnet, gateway and the multicast group each stream sends to, and StatusID.ParamEthernet* reports what that connector resolved and negotiated. Reach them with the *_with_param accessors, passing the connector's zero-based index; AttributeID.NumberOfEthernetConnectors counts them. ConfigurationID.ConfigEthernetPTP* covers the device-wide PTP domain, priorities and FollowerOnly. Addresses are dotted-quad strings, since set_config_int on one answers E_INVALIDARG:

cfg, status = pydecklink.ConfigurationID, pydecklink.StatusID
dev.set_config_string_with_param(
    cfg.ConfigParamEthernetStaticLocalIPAddress, 1, "192.0.2.40"
)
dev.get_status_int_with_param(status.ParamEthernetLink, 1)

StatisticID reads PTP lock, temperature, per-connector packet counts and the optical module's readings through get_statistic_*.

Each sub-device's streams are IPFlows, one per essence and direction, from dev.ip_extensions. An output flow's status reads the SDP the card offers; an input flow takes the SDP of the peer it receives, and enable() starts it. The card answers success to an SDP it rejects and keeps the previous one, so read the setting back:

D, T, S = pydecklink.IPFlowDirection, pydecklink.IPFlowType, pydecklink.IPFlowSettingID
video_in = next(
    f for f in dev.ip_extensions.get_ip_flows()
    if f.direction == D.Input and f.type == T.Video
)
video_in.set_setting_string(S.PeerSDP, peer_sdp)
assert video_in.get_setting_string(S.PeerSDP) == peer_sdp
video_in.enable()

Frames — CaptureFrame, CaptureFrameRef (zero-copy), and MutableFrame expose pixel data as a numpy array via .data, alongside .width, .height, .row_bytes.

Enums — DisplayMode, PixelFormat, VideoConnection, VideoInputFlag, VideoOutputFlag, FieldDominance, IPFlowDirection, IPFlowType, and the ConfigurationID, AttributeID, StatusID and IPFlow*ID identifier sets the config, attribute, status and flow accessors take.

Custom memory — VideoBufferAllocator / VideoBufferAllocatorProvider back capture and playback with caller-owned buffers (e.g. CUDA pinned memory) for direct GPU DMA. Connector profiles — ProfileManager, Profile, and ProfileID switch a card's duplex/sub-device layout.

License

BSD-3-Clause — see LICENSE.