如何通过GStreamer获取视频轨道的净光圈与编码尺寸？

DevOps 小满

2026-7-9

解决方案

获取编码尺寸

GstDiscovererVideoInfo封装了底层的GstVideoInfo结构，你可以通过它直接提取编码维度：

g_autoptr(GstDiscovererVideoInfo) video_info = GST_DISCOVERER_VIDEO_INFO(stream_iter->data);
const GstVideoInfo *base_info = gst_discoverer_video_info_get_video_info(video_info);

// 提取编码宽高
video_metadata[EncodedWidth] = std::to_string(gst_video_info_get_encoded_width(base_info));
video_metadata[EncodedHeight] = std::to_string(gst_video_info_get_encoded_height(base_info));

获取净光圈（Clean Aperture）

净光圈信息存储在视频流的Caps结构中，需要从GstDiscovererVideoInfo中提取Caps后，解析对应的字段：

GstCaps *caps = gst_discoverer_video_info_get_caps(video_info);
GstStructure *caps_struct = gst_caps_get_structure(caps, 0);

gint ca_width, ca_height, ca_x_offset, ca_y_offset;

// 先检查字段是否存在，再提取参数
if (gst_structure_get_int(caps_struct, "clean-aperture-width", &ca_width) &&
    gst_structure_get_int(caps_struct, "clean-aperture-height", &ca_height) &&
    gst_structure_get_int(caps_struct, "clean-aperture-x-offset", &ca_x_offset) &&
    gst_structure_get_int(caps_struct, "clean-aperture-y-offset", &ca_y_offset)) {
    video_metadata[CleanApertureWidth] = std::to_string(ca_width);
    video_metadata[CleanApertureHeight] = std::to_string(ca_height);
    video_metadata[CleanApertureXOffset] = std::to_string(ca_x_offset);
    video_metadata[CleanApertureYOffset] = std::to_string(ca_y_offset);
} else {
    // 处理无净光圈信息的情况，比如设默认值或跳过该字段
}