Gstreamer-camera数据采集

用于需要采集当前设备camera数据，并做后续处理

// 采集导数据后处理

GstFlowReturn handle_sample(GstElement *sink, gpointer user_data, gboolean isH264)

{

    ICameraSdkEvent *_event = (ICameraSdkEvent *)user_data;

    if (!_event) {

        return GST_FLOW_OK;

    }

    GstSample *sample = NULL;

    GstBuffer *buffer = NULL;

    g_signal_emit_by_name(sink, "pull-sample", &sample);

    if (!sample) {

        g_printerr("[camera_sdk_impl.cpp][handle_sample], sample is NULL!!!");

        return GST_FLOW_OK;

    }

    GstBuffer *buf = gst_sample_get_buffer(sample);

    GstMapInfo map_info;

    if (!gst_buffer_map(buf, &map_info, GST_MAP_READ)) {

        g_printerr("[camera_sdk_impl.cpp][handle_sample], frameData map error");

        return GST_FLOW_OK;

    }

    // 发送或做其他处理，数据map_info.data，数据大小map_info.size

    gst_buffer_unmap(buf, &map_info);

    gst_sample_unref(sample);

    return GST_FLOW_OK;

}

// 初始化 pipeline

//  |------------------pipeline----------------|

//  | v4l2src->capsfilter->mpph264enc->appsink |

//  |------------------------------------------|

bool init(const char *dev, int pictureWidth, int pictureHeight, int frameRate)

{

    m_v4l2_src = gst_element_factory_make("v4l2src", "v4l2_src");

    if (!m_v4l2_src) {

        g_printerr("[init], v4l2src elements could be created.\n");

        return false;

    }

    m_mpph264_enc = gst_element_factory_make("mpph264enc", "mpph264_enc");

    if (!m_mpph264_enc) {

        g_printerr("[init], mpph264enc elements could be created.\n");

        return false;

    }

    m_app_sink_video_1 = gst_element_factory_make("appsink", "app_sink_video_1");

    if (!m_app_sink_video_1) {

        g_printerr("[init], app_sink_video elements could be created.\n");

        return false;

    }

    m_pipeline = gst_pipeline_new("camera-pipeline");

    if (!m_pipeline) {

        g_printerr("[init], pipeline elements could be created.\n");

        return false;

    }

    g_object_set(G_OBJECT(m_v4l2_src), "device", dev, NULL);

    g_object_set(G_OBJECT(m_app_sink_video_1), "enable-last-sample", FALSE, NULL);

    g_object_set(G_OBJECT(m_app_sink_video_1), "sync", FALSE, "async", FALSE, NULL);

    g_object_set(G_OBJECT(m_app_sink_video_1), "max-lateness", 0, NULL);

    g_object_set(G_OBJECT(m_app_sink_video_1), "drop", TRUE, "max-buffers", 1, NULL);

    g_object_set(G_OBJECT(m_app_sink_video_1), "emit-signals", TRUE, NULL);

    g_signal_connect(m_app_sink_video_1, "new-sample", G_CALLBACK(cb_appsink_video_new_sample_1), m_cameraEvent);

    g_object_set(G_OBJECT(m_mpph264_enc), "gop", 100, NULL);

    g_object_set(G_OBJECT(m_mpph264_enc), "header-mode", 1, NULL);

    g_object_set(G_OBJECT(m_mpph264_enc), "qos", TRUE, NULL);

    m_caps_filter_1 = gst_element_factory_make("capsfilter", "caps_filter_1");

    if (!m_caps_filter_1) {

        g_printerr("[init], caps_filter elements could be created.\n");

        return false;

    }

    // 320 x 240

    GstCaps *caps_1 = gst_caps_new_simple("video/x-raw", "format", G_TYPE_STRING, "NV12", "width", G_TYPE_INT,

        pictureWidth, "height", G_TYPE_INT, pictureHeight, "framerate", GST_TYPE_FRACTION, frameRate, 1, NULL);

    if (!caps_1) {

        g_printerr("[init], caps new fail.\n");

        return false;

    }

    g_object_set(G_OBJECT(m_caps_filter_1), "caps", caps_1, NULL);

    gst_caps_unref(caps_1);

    gst_bin_add_many(GST_BIN(m_pipeline), m_v4l2_src, NULL);

    gst_bin_add_many(GST_BIN(m_pipeline), m_caps_filter_1, NULL);

    gst_bin_add_many(GST_BIN(m_pipeline), m_mpph264_enc, NULL);

    gst_bin_add_many(GST_BIN(m_pipeline), m_app_sink_video_1, NULL);

    if (gst_element_link_many(m_v4l2_src, m_caps_filter_1, m_mpph264_enc, m_app_sink_video_1, NULL) != TRUE) {

        g_printerr("[init], element all link fail.\n");

        return false;

    }

    if (gst_element_set_state(m_pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {

        g_printerr("[init], play failed...\n");

        return false;

    }

    printf("[init], open camera devcie successfully..\n");

    return true;

}