Camera Monitoring API#

It is called within the scope of the oasis::ui namespace.

Header File#

OasisPreview.h

PreviewFrameObserver Interface#

A user-defined observer object derived from PreviewFrameObserver can be specified for a Preview object using the setPreviewFrameObserver function.

The application can obtain video frames displayed on the screen through the onFrame callback function.

class PreviewFrameObserver : public std::enable_shared_from_this<PreviewFrameObserver>
{
public:
    PreviewFrameObserver();
    virtual ~PreviewFrameObserver();
    virtual void onFrame(int32_t camera_id, uint8_t *frame, int32_t stride_width, int32_t width, int32_t height);
    virtual void onNoMediaData(int32_t camera_id);
};

When the video frame format is YUV420, the Y, U, and V channels can be obtained using the formula below:

uint8_t *y = frame;
uint8_t *u = frame + stride_width * height;
uint8_t *v = u + stride_width * height / 4;

Functions#

The key-value map values for each video channel are prefixed with channel<N>- before each key name. <N> starts from 1 and increases by 1.

Example#

Below is an example of monitoring video from the camera device ID 0.

Initializes Oasis.

// Does not use the file system.

oasis::key_value_map_t parameters;

parameters["offs-disable"] = "1";

if(oasis::initialize(parameters) < 0) {
    DLOG(DLOG_ERROR, "Oasis init failed\n");
    return -1;
}

Initializes the camera device. Here, a single camera device is used.

parameters.clear();

parameters["source-count"] = "1";

parameters["source1-camera-id"] = "0";
parameters["source1-isp-id"] = "0";
parameters["source1-isp-wdr-mode"] = "0";
parameters["source1-capture-format"] = "YUV420";
parameters["source1-capture-buffers"] = "5";
parameters["source1-fps"] = "30";
parameters["source1-subchannel-rotation"] = "0";
parameters["source1-loc"] = "front";
parameters["source1-capture-resolution"] = "1080p";
parameters["source1-sensor-config"] = "./Resource_tp2863/VIC/0/tp2863_1920x1080_ch0.cfg";
parameters["source1-autoscene-config"] = "./Resource_tp2863/AutoScene/autoscene_conf.cfg";
parameters["source1-resource-dir"] = "./Resource_tp2863/";

configCameras(parameters);  

Initializes the display device.

parameters.clear();

parameters["memory-type"] = "ion"; //cma
parameters["screen-width"] = "480";
parameters["screen-height"] = "320";

display::setup(parameters);

Configures the GUI. In this example, touch is not used.

parameters.clear();

parameters["system-font-size"] = "10";
parameters["system-font-path"] = "/mnt/sd/consola.ttf";
parameters["display-rotation"] = "0";
parameters["enable-touch"] = "0";

err = ui::setup(parameters);
if (err < 0) {
    DLOG(DLOG_ERROR, "Oasis ui::setup failed\n");
    return -1;
}

Initializes the Preview object.

parameters.clear();

// Obtains the default screen object and applies its width and height to the media player.
ui::ScreenRef screen = ui::getDefaultScreen();

int32_t screen_width = ui::screenWidth(screen);
int32_t screen_height = ui::screenHeight(screen);


// Creates a user-defined object derived from ui::PreviewFrameObserver.
std::shared_ptr<MyPreviewFrameObserver> observer = std::make_shared<MyPreviewFrameObserver>();

parameters["channel-count"] = "1";
parameters["primary-channel"] = "1";

parameters["channel1-camera-id"] = std::to_string(camera_id);
parameters["channel1-visible"] = "1";
parameters["channel1-rotation"] = std::to_string(rotation);
// Configures the playback screen to full screen.
parameters["channel1-x"] = "0";
parameters["channel1-y"] = "0";
parameters["channel1-width"] = std::to_string(screen_width);
parameters["channel1-height"] = std::to_string(screen_height);
parameters["channel1-zorder"] = "0";

ui::PreviewRef preview = ui::createPreview(0, parameters);
ui::setPreviewFrameObserver(preview, observer);

Configures the screen layout. A Fixed layout container is used inside the top-level Window object, and the video screen is set to full screen.

ui::WindowRef preview_panel = ui::createWindow("Preview1");

ui::FixedRef fixed_layout = ui::createFixed();
ui::containerAdd(preview_panel, fixed_layout);

ui::setFixedSize(preview, screen_width, screen_height);
ui::fixedPut(fixed_layout, preview, 0, 0);
ui::screenAdd(screen, preview_panel);

ui::setVisible(preview_panel, true);

Starts monitoring.

ui::previewStart(preview);

An example of modifying the screen position during playback:

ui::previewSetPos(preview, 0, 100, 100)

Stops monitoring.

ui::previewStop(preview);

Below is the complete code:

#include "OasisAPI.h"
#include "OasisLog.h"
#include "OasisMedia.h"
#include "OasisUI.h"
#include "OasisFS.h"
#include "OasisUtil.h"
#include "OasisDisplay.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>

#include <signal.h>

#include <thread>
#include <mutex>
#include <memory>
#include <condition_variable>

using namespace oasis;


static bool continue_previewing = true;

void cancel_handler(int signum)
{
    continue_previewing = false;
}

class MyPreviewFrameObserver : public ui::PreviewFrameObserver {
public:
    MyPreviewFrameObserver() {}
    virtual ~MyPreviewFrameObserver() {}

    virtual void onFrame(int32_t camera_id, uint8_t *frame, int32_t stride_width, int32_t width, int32_t height) {
    }
    virtual void onNoMediaData(int32_t camera_id) {
        fprintf(stdout, "no media: camera<%d>\n", camera_id);
    }
};

void printUsage(const char *pgname)
{
    fprintf(stderr, "USAGE: %s [-r <rotation. 90, 270>] <camera id>\n", pgname);
}

int main(int argc, char *argv[])
{
    int32_t err;
    int c;
    int32_t rotation = 0;
    int32_t camera_id = -1;

    opterr = 0;
    while ((c = getopt(argc, argv, "r:h")) != -1) {
        switch (c) {
        case 'r':
            if(optarg == nullptr) {
                fprintf(stderr, "error: bad option argument '%c'\n", optopt);
                return -1;
            }
            rotation = atoi(optarg);
            if(rotation != 0 && rotation != 90 /*&& rotation != 180*/ && rotation != 270) {
                fprintf(stderr, "bad rotation: %d\n", rotation);
                return -1;
            }
            break;
        case 'h':
        default:
            printUsage(argv[0]);
            return -1;
        }
    }

    if(argc-optind < 1) {
        fprintf(stderr, "error: invalid or insufficient arguments (%d, %d)\n", argc, optind);
        printUsage(argv[0]);
        return -1;
    }

    camera_id = atoi(argv[optind]);
    if(camera_id < 0) {
        fprintf(stderr, "invalid camera id: %d\n", camera_id);
        return -1;
    }


    signal(SIGINT, cancel_handler);

    oasis::key_value_map_t parameters;

    ////////////////////////////////////////////////////////////////////////////////////////////
    // init

    parameters["offs-disable"] = "1";

    if(oasis::initialize(parameters) < 0) {
        DLOG(DLOG_ERROR, "Oasis init failed\n");
        return -1;
    }

    ////////////////////////////////////////////////////////////////////////////////////////////
    // camera sources
    parameters.clear();

    parameters["source-count"] = "1";

    parameters["source1-camera-id"] = "0";
    parameters["source1-isp-id"] = "0";
    parameters["source1-isp-wdr-mode"] = "0";
    parameters["source1-capture-format"] = "YUV420";
    parameters["source1-capture-buffers"] = "5";
    parameters["source1-fps"] = "30";
    parameters["source1-subchannel-rotation"] = "0";
    parameters["source1-loc"] = "front";
    parameters["source1-capture-resolution"] = "1080p";
    parameters["source1-sensor-config"] = "./Resource_tp2863/VIC/0/tp2863_1920x1080_ch0.cfg";
    parameters["source1-autoscene-config"] = "./Resource_tp2863/AutoScene/autoscene_conf.cfg";
    parameters["source1-resource-dir"] = "./Resource_tp2863/";

    configCameras(parameters);  

    ////////////////////////////////////////////////////////////////////////////////////////////
    // display setup
    parameters.clear();

    parameters["memory-type"] = "ion"; //cma
    parameters["screen-width"] = "480";
    parameters["screen-height"] = "320";

    display::setup(parameters);


    //////////////////////////////////////////////////////////////////////////////////////////
    // ui setup
    parameters.clear();

    parameters["system-font-size"] = "10";
    parameters["system-font-path"] = "/mnt/sd/consola.ttf";

    parameters["display-rotation"] = "0";
    parameters["enable-touch"] = "0";

    err = ui::setup(parameters);
    if (err < 0) {
        DLOG(DLOG_ERROR, "Oasis ui::setup failed\n");
        return -1;
    }

    /////////////////////////////////////////////////////////////////////////
    // create preview and layout

    ui::ScreenRef screen = ui::getDefaultScreen();

    int32_t screen_width = ui::screenWidth(screen);
    int32_t screen_height = ui::screenHeight(screen);


    parameters.clear();


    //preview_panel
    ui::WindowRef preview_panel = ui::createWindow("Preview1");

    ui::FixedRef fixed_layout = ui::createFixed();
    ui::containerAdd(preview_panel, fixed_layout);

    std::shared_ptr<MyPreviewFrameObserver> observer = std::make_shared<MyPreviewFrameObserver>();

    parameters["channel-count"] = "1";
    parameters["primary-channel"] = "1";

    parameters["channel1-camera-id"] = std::to_string(camera_id);
    parameters["channel1-visible"] = "1";
    parameters["channel1-rotation"] = std::to_string(rotation);
    parameters["channel1-x"] = "0";
    parameters["channel1-y"] = "0";
    parameters["channel1-width"] = std::to_string(screen_width);
    parameters["channel1-height"] = std::to_string(screen_height);
    parameters["channel1-zorder"] = "0";

    ui::PreviewRef preview = ui::createPreview(0, parameters);
    ui::setPreviewFrameObserver(preview, observer);

    ui::setFixedSize(preview, screen_width, screen_height);
    ui::fixedPut(fixed_layout, preview, 0, 0);
    ui::screenAdd(screen, preview_panel);

    ui::setVisible(preview_panel, true);

    ui::previewStart(preview);

    do {
        usleep(100000);
    } while (continue_previewing);

    ui::previewStop(preview);

    err = ui::cleanup();

    oasis::finalize();

    return 0;
}