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Hololink CSI to Bayer GPU-Resident Operator#

Authors: Holoscan Team (NVIDIA)
Supported platforms: aarch64
Language: C++
Last modified: March 13, 2026
Latest version: 0.1.0
Minimum Holoscan SDK version: 4.0.0
Tested Holoscan SDK versions: 4.0.0
Contribution metric: Level 1 - Highly Reliable

This operator converts CSI (Camera Serial Interface) packed data to Bayer format using GPU-resident processing. It supports RAW8, RAW10, and RAW12 pixel formats.

Overview#

The CsiToBayerGpuResidentOp is a GPU-resident Holoscan operator that:

  • Receives packed CSI data from camera sensors
  • Unpacks the data to 16-bit Bayer format
  • Operates entirely on GPU memory for low-latency processing

Requirements#

  • Holoscan SDK 4.0.0 or later
  • Holoscan Sensor Bridge ("Hololink") library installed and available
  • CUDA-capable GPU

Usage#

C++#

#include <csi_to_bayer_gpu_resident/csi_to_bayer_gpu_resident.hpp>

// In your application setup:
auto csi_to_bayer = make_operator<hololink::operators::CsiToBayerGpuResidentOp>("csi_to_bayer");

// Configure the operator before initialization
csi_to_bayer->configure(
    start_byte,       // Offset to first pixel data
    bytes_per_line,   // Bytes per line in CSI data
    pixel_width,      // Image width in pixels
    pixel_height,     // Image height in pixels
    pixel_format,     // hololink::csi::PixelFormat::RAW_8/RAW_10/RAW_12
    trailing_bytes    // Trailing bytes after image data
);

// Add to your pipeline
add_flow(receiver, csi_to_bayer, ('out', 'in'));
add_flow(csi_to_bayer, next_operator, ('out', 'in'));

Supported Pixel Formats#

  • RAW_8: 8-bit raw data, unpacked to 16-bit (upper 8 bits)
  • RAW_10: 10-bit raw data (4 pixels packed in 5 bytes), unpacked to 16-bit
  • RAW_12: 12-bit raw data (2 pixels packed in 3 bytes), unpacked to 16-bit

Build#

This operator is built as part of the HoloHub build system:

./run build csi_to_bayer_gpu_resident

Dependencies#

  • hololink::core - Core hololink library
  • hololink::common - Common hololink utilities (CUDA helpers)
  • holoscan::core - Holoscan SDK
  • fmt - Formatting library
  • CUDA - CUDA driver API

API Reference#

C++#

hololink::operators::CsiToBayerConverterBase#

Inherits from: hololink::csi::CsiConverter

Base CSI-to-Bayer conversion state and CsiConverter implementation. Used by both CsiToBayerOp and CsiToBayerGpuResidentOp to avoid code duplication.

Methods#
Method Description
uint32_t receiver_start_byte() override
uint32_t received_line_bytes(uint32_t line_bytes) override
uint32_t transmitted_line_bytes(hololink::csi::PixelFormat pixel_format, uint32_t pixel_width) override
void configure(uint32_t start_byte, uint32_t bytes_per_line, uint32_t pixel_width, uint32_t pixel_height, hololink::csi::PixelFormat pixel_format, uint32_t trailing_bytes) override
size_t get_csi_length() const
size_t get_frame_size() const

hololink::operators::CsiToBayerGpuResidentOp#

Inherits from: holoscan::GPUResidentOperator, hololink::operators::CsiToBayerConverterBase

Methods#
Method Description
void setup(holoscan::OperatorSpec &spec) override
void initialize() override
void stop() override
void compute(holoscan::InputContext &, holoscan::OutputContext &, holoscan::ExecutionContext &) override