select_tracks_for_object

static GPtrArray*
select_tracks_for_object(GESTimeline* timeline, GESClip* clip, GESTrackElement* tr_object, gpointer user_data)
{
    GPtrArray* result = NULL;

    std::lock_guard<std::mutex> lck(timelines_mtx);

    auto it = timelines.find(timeline);
    if (it != timelines.end())
    {
        auto timeline_data = it->second;
        auto skip = false;

        // if the clip was found, use stream selection logic to possibly skip this GESTrackElement
        auto it2 = timeline_data->clips.find(clip);
        if (it2 != timeline_data->clips.end())
        {
            auto clip_data = it2->second;

            const gchar* name = ges_uri_clip_get_uri(GES_URI_CLIP(clip));
            gchar target_stream_id[256] = { 0 };


            if (GES_IS_URI_CLIP_ASSET(GES_TIMELINE_ELEMENT(clip)->asset))
            {
                auto clip_asset = GES_URI_CLIP_ASSET(GES_TIMELINE_ELEMENT(clip)->asset);
                auto info = ges_uri_clip_asset_get_info(clip_asset);

                auto streams = gst_discoverer_info_get_audio_streams(info);

                int stream_idx = 0;
                for (GList* tmp = streams; tmp; tmp = tmp->next)
                {
                    if (GST_IS_DISCOVERER_AUDIO_INFO(tmp->data))
                    {
                        const gchar* stream_id = gst_discoverer_stream_info_get_stream_id(GST_DISCOVERER_STREAM_INFO(tmp->data));

                        if (stream_idx == clip_data->target_stream)
                        {
                            strcpy(target_stream_id, stream_id);
                            g_print("Correct stream id: %s\n", stream_id);
                            break;
                        }
                        stream_idx++;
                    }
                }
            }

            GESAsset* asset = ges_extractable_get_asset(GES_EXTRACTABLE(tr_object));

            if (GES_IS_URI_SOURCE_ASSET(asset))
            {
                GstDiscovererStreamInfo* stream_info = ges_uri_source_asset_get_stream_info(GES_URI_SOURCE_ASSET(asset));

                const gchar* stream_id = gst_discoverer_stream_info_get_stream_id(stream_info);
                g_print("StreamID: %s, Clip: %s, Stream Caps: %s, target_stream = %d\n", stream_id, name, gst_caps_to_string(gst_discoverer_stream_info_get_caps(stream_info)), clip_data->target_stream);

                if (strcmp(target_stream_id, stream_id) != 0)
                {
                    skip = true;
                    g_print("skipping...\n");
                }
            }
        }
        else
        {
            g_print("[CLIP WAS NOT FOUND]\n");
        }

        if (!skip)
        {
            result = g_ptr_array_new();

            for (GList* tmp = timeline->tracks; tmp; tmp = tmp->next)
            {
                GESTrack* track = GES_TRACK(tmp->data);

                if ((track->type & ges_track_element_get_track_type(tr_object)))
                {
                    GESAsset* asset = ges_extractable_get_asset(GES_EXTRACTABLE(tr_object));

                    if (GES_IS_URI_SOURCE_ASSET(asset))
                    {
                        GstDiscovererStreamInfo* stream_info = ges_uri_source_asset_get_stream_info(GES_URI_SOURCE_ASSET(asset));

                        const gchar* stream_id = gst_discoverer_stream_info_get_stream_id(stream_info);
                        g_print("[SELECTED STREAM ID]: %s\n", stream_id);
                    }
                    else
                    {
                        const gchar* name = G_OBJECT_TYPE_NAME(tr_object);
                        g_print("[WHAT IS THIS?!?]: %s\n", name);
                    }

                    gst_object_ref(track);
                    g_ptr_array_add(result, track);
                    break;
                }
            }
        }
    }

    return result;
}