C++ SDK Reference

libaiden.a is the project's C++ hardware SDK, with the main header file:

#include "aiden_sdk.h"

Key capabilities:

1. GPIO wakeup event;
2. Audio capture;
3. Audio playback;
4. HDMI / camera frame capture;
5. USB HID auxiliary capabilities.

AudioConfig

struct AudioConfig {
    const char* device_name = "hw:0,0";
    int sample_rate = 16000;
    int channels = 1;
    int bit_width = 16;
};

CameraConfig

struct CameraConfig {
    const char* device_name = "/dev/video0";
    int width = 1920;
    int height = 1080;
    int camera_id = 0;
    const char* pixel_format = "uyvy";
    const char* subdev_device = "/dev/v4l-subdev2";
    const char* edid_path = nullptr;
    int skip_frames = 1;
    int trigger_retries = 0;
    int trigger_delay_ms = 1000;
    int capture_retries = 2;
    bool enable_hdmi_sync = true;
    bool force_trigger = false;
    bool require_exact_resolution = false;
    bool reject_uniform_frames = true;
};

frame_service overrides the two timing flags above and requires the negotiated 1920x1080 resolution. The RK628D path avoids forced EDID/HPD retriggering and retains the driver-provided EDID. The TC358743 path performs one startup EDID/HPD renegotiation, then queries the settled timings.

WakeupListener

#include "aiden_sdk.h"

void on_wakeup() {
    printf("Wakeup detected!\n");
}

aiden::WakeupListener listener;
listener.start(33, on_wakeup);
// ...
listener.stop();

GPIO 33/GPIO 32 are typically used for button or wakeup signals, triggered on falling edge. When you need to listen on both pins simultaneously, create two WakeupListener instances and bind them to the same callback.

AudioCapture

aiden::AudioConfig config;
config.sample_rate = 16000;
config.channels = 1;
config.bit_width = 16;

aiden::AudioCapture capture;
capture.init(config);
capture.start([](const aiden::AudioFrame& frame) {
    printf("Got %u bytes\n", frame.length);
});
// ...
capture.stop();

AudioPlayer

aiden::AudioConfig config;
config.sample_rate = 16000;
config.channels = 1;
config.bit_width = 16;

aiden::AudioPlayer player;
player.init(config);
player.set_volume(80); // 0..100
player.play(samples, sizeof(samples));
player.stop();

CameraCapture

CameraCapture preserves the historical direct-capture default of UYVY for compatibility. The frame_service executable selects NV12 explicitly. With NV12, the capture_frame* copy helpers remove V4L2 row padding and return a tight Y + interleaved UV payload. The returned VideoFrame::stride is the visible width and size_image/length are the compact payload size.

Streaming capture:

aiden::CameraConfig config;
config.width = 1920;
config.height = 1080;
config.pixel_format = "uyvy";

aiden::CameraCapture camera;
camera.init(config);
camera.start([](const aiden::VideoFrame& frame) {
    printf("Frame: %ux%u, %u bytes, stride=%u\n",
           frame.width, frame.height, frame.length, frame.stride);
});
// ...
camera.stop();

Pause and resume streaming while retaining the open device and MMAP buffers:

aiden::CameraCapture camera;
camera.init(config);
camera.pause();  // VIDIOC_STREAMOFF; device and mappings remain owned

// Later, when a frame is needed:
camera.resume(); // requeue buffers and VIDIOC_STREAMON
aiden::VideoFrame frame;
std::vector<uint8_t> bytes;
camera.capture_frame(frame, bytes);
camera.pause();

frame_service uses this lifecycle for request-driven screenshots. Resume resets skip_frames, then the service performs additional zero-copy warm-up dequeues before the response frame is copied. The deployed default is zero additional warm-up frames when streaming restarts per request and six when keep_streamon keeps the stream active.

One-shot capture and copy to caller-owned buffer:

aiden::CameraConfig config;
config.edid_path = nullptr; // Use built-in 1080p60-only CTA EDID

aiden::CameraCapture camera;
aiden::VideoFrame frame;
std::vector<uint8_t> bytes;

if (camera.capture_once(config, frame, bytes)) {
    printf("Frame: %ux%u, %u bytes\n", frame.width, frame.height, frame.length);
}

Dependencies

• Rockchip MPI / Rockit / MPP / RGA / IVE libraries;
• opencv-mobile;
• System libraries such as pthread, m;
• Corresponding header and library paths are configured in CMakeLists.txt.

Notes

• The SDK initializes RK_MPI_SYS_Init() on first use;
• Blocking operations support graceful shutdown according to service logic;
• When using frame_service, applications should typically not open /dev/video0 directly.