GstVideoAggregator — Base class for video aggregators

Types and Values

Object Hierarchy

    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstElement
                ╰── GstAggregator
                    ╰── GstVideoAggregator


#include <gst/video/video.h>


VideoAggregator can accept AYUV, ARGB and BGRA video streams. For each of the requested sink pads it will compare the incoming geometry and framerate to define the output parameters. Indeed output video frames will have the geometry of the biggest incoming video stream and the framerate of the fastest incoming one.

VideoAggregator will do colorspace conversion.

Zorder for each input stream can be configured on the GstVideoAggregatorPad.


Types and Values

struct GstVideoAggregator

struct GstVideoAggregator {
  /* Output caps */
  GstVideoInfo               info;


GstVideoInfo info;

The GstVideoInfo representing the currently set srcpad caps.


struct GstVideoAggregatorClass

struct GstVideoAggregatorClass {
  GstCaps *          (*update_caps)               (GstVideoAggregator *  videoaggregator,
                                                   GstCaps            *  caps);
  GstFlowReturn      (*aggregate_frames)          (GstVideoAggregator *  videoaggregator,
                                                   GstBuffer          *  outbuffer);
  GstFlowReturn      (*create_output_buffer)      (GstVideoAggregator *  videoaggregator,
                                                   GstBuffer          ** outbuffer);
  void               (*find_best_format)          (GstVideoAggregator *  vagg,
                                                   GstCaps            *  downstream_caps,
                                                   GstVideoInfo       *  best_info,
                                                   gboolean           *  at_least_one_alpha);


update_caps ()

Optional. Lets subclasses update the GstCaps representing the src pad caps before usage. Return NULL to indicate failure.


aggregate_frames ()

Lets subclasses aggregate frames that are ready. Subclasses should iterate the GstElement.sinkpads and use the already mapped GstVideoFrame from gst_video_aggregator_pad_get_prepared_frame() or directly use the GstBuffer from gst_video_aggregator_pad_get_current_buffer() if it needs to map the buffer in a special way. The result of the aggregation should land in outbuffer .


create_output_buffer ()

Optional. Lets subclasses provide a GstBuffer to be used as outbuffer of the aggregate_frames vmethod.


find_best_format ()

Optional. Lets subclasses decide of the best common format to use.