qmlgl6src: Use downstream pool when available

This make use of the pool that has been negotiated with downstream in the
decide_allocation function.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7904>

subprojects/gst-plugins-good/ext/qt6/gstqml6glsrc.cc

@@ -333,7 +333,7 @@ gst_qml6_gl_src_decide_allocation (GstBaseSrc * bsrc, GstQuery * query)
   GstStructure *config;
   GstCaps *caps;
   guint min, max, size, n, i;
-  gboolean update_pool, update_allocator;
+  gboolean update_allocator;
   GstAllocator *allocator;
   GstAllocationParams params;
   GstGLVideoAllocationParams *glparams;
@@ -355,22 +355,16 @@ gst_qml6_gl_src_decide_allocation (GstBaseSrc * bsrc, GstQuery * query)
 
   n = gst_query_get_n_allocation_pools (query);
   if (n > 0) {
-    update_pool = TRUE;
     for (i = 0; i < n; i++) {
       gst_query_parse_nth_allocation_pool (query, i, &pool, &size, &min, &max);
 
-      if (!pool || !GST_IS_GL_BUFFER_POOL (pool)) {
-        if (pool)
-          gst_object_unref (pool);
-        pool = NULL;
-      }
-    }
-  }
+      if (pool && GST_IS_GL_BUFFER_POOL (pool))
+        break;
 
-  if (!pool) {
-    size = vinfo.size;
-    min = max = 0;
-    update_pool = FALSE;
+      if (pool)
+        gst_object_unref (pool);
+      pool = NULL;
+    }
   }
 
   if (!qt_src->context && !_find_local_gl_context (qt_src))
@@ -383,6 +377,8 @@ gst_qml6_gl_src_decide_allocation (GstBaseSrc * bsrc, GstQuery * query)
     if (!qt_src->context || !GST_IS_GL_CONTEXT (qt_src->context))
       return FALSE;
 
+    size = vinfo.size;
+    min = max = 0;
     pool = gst_gl_buffer_pool_new (qt_src->context);
     GST_INFO_OBJECT (qt_src, "No pool, create one ourself %p", pool);
   }
@@ -423,10 +419,11 @@ gst_qml6_gl_src_decide_allocation (GstBaseSrc * bsrc, GstQuery * query)
   if (allocator)
     gst_object_unref (allocator);
 
-  if (update_pool)
+  if (n > 0)
     gst_query_set_nth_allocation_pool (query, 0, pool, size, min, max);
   else
     gst_query_add_allocation_pool (query, pool, size, min, max);
+
   gst_object_unref (pool);
 
   GST_INFO_OBJECT (qt_src, "successfully decide_allocation");
@@ -437,20 +434,34 @@ static GstFlowReturn
 gst_qml6_gl_src_create (GstPushSrc * psrc, GstBuffer ** buffer)
 {
   GstQml6GLSrc *qt_src = GST_QML6_GL_SRC (psrc);
-  GstCaps *updated_caps = NULL;
+  gboolean updated_caps = FALSE;
   GstGLContext* context = qt_src->context;
   GstGLSyncMeta *sync_meta;
 
+retry:
   *buffer = qt6_gl_window_take_buffer (qt_src->window, &updated_caps);
-  GST_DEBUG_OBJECT (qt_src, "produced buffer %p", *buffer);
-  if (!*buffer)
-    return GST_FLOW_FLUSHING;
 
   if (updated_caps) {
-    GST_DEBUG_OBJECT (qt_src, "new_caps %" GST_PTR_FORMAT, updated_caps);
-    gst_base_src_set_caps (GST_BASE_SRC (qt_src), updated_caps);
+    QSize size = qt_src->qwindow->size();
+
+    /* avoid spurious renegotiation */
+    if (GST_VIDEO_INFO_WIDTH (&qt_src->v_info) != size.width()
+        || GST_VIDEO_INFO_HEIGHT (&qt_src->v_info) != size.height()) {
+      GST_DEBUG_OBJECT (qt_src, "renegotiation needed");
+      if (!gst_base_src_negotiate (GST_BASE_SRC (qt_src)))
+        return GST_FLOW_NOT_NEGOTIATED;
+    }
+
+    qt6_gl_window_set_pool (qt_src->window,
+        gst_base_src_get_buffer_pool (GST_BASE_SRC (qt_src)));
+    updated_caps = FALSE;
+    goto retry;
   }
-  gst_clear_caps (&updated_caps);
+
+  GST_DEBUG_OBJECT (qt_src, "produced buffer %p", *buffer);
+
+  if (!*buffer)
+    return GST_FLOW_FLUSHING;
 
   sync_meta = gst_buffer_get_gl_sync_meta(*buffer);
   if (sync_meta)

subprojects/gst-plugins-good/ext/qt6/qt6glwindow.cc

@@ -60,9 +60,8 @@ struct _Qt6GLWindowPrivate
   GstBuffer *buffer;
   GstVideoInfo v_info;
   GstVideoFrame mapped_frame;
-  GstGLBaseMemoryAllocator *gl_allocator;
-  GstGLAllocationParams *gl_params;
   GLenum internal_format;
+  GstBufferPool *pool;
 
   gboolean initted;
   gboolean updated;
@@ -122,13 +121,9 @@ Qt6GLWindow::~Qt6GLWindow()
   gst_clear_object (&this->priv->other_context);
   gst_clear_buffer (&this->priv->buffer);
   gst_clear_buffer (&this->priv->produced_buffer);
+  gst_clear_object (&this->priv->pool);
   gst_clear_object (&this->priv->display);
   gst_clear_object (&this->priv->context);
-  gst_clear_object (&this->priv->gl_allocator);
-
-  if (this->priv->gl_params)
-    gst_gl_allocation_params_free (this->priv->gl_params);
-  this->priv->gl_params = NULL;
 
   g_free (this->priv);
   this->priv = NULL;
@@ -145,46 +140,43 @@ Qt6GLWindow::beforeRendering()
     return;
   }
 
+  if (this->priv->buffer) {
+    GST_ERROR ("A rendering already started, something went wrong.");
+    g_mutex_unlock (&this->priv->lock);
+    return;
+  }
+
   QSize size = source->size();
-
-  if (!this->priv->gl_allocator)
-    this->priv->gl_allocator =
-        (GstGLBaseMemoryAllocator *) gst_gl_memory_allocator_get_default (this->priv->context);
-
-  if (GST_VIDEO_INFO_WIDTH (&this->priv->v_info) != size.width()
+  if (!this->priv->pool
+      || GST_VIDEO_INFO_WIDTH (&this->priv->v_info) != size.width()
       || GST_VIDEO_INFO_HEIGHT (&this->priv->v_info) != size.height()) {
     this->priv->new_caps = TRUE;
-
     gst_video_info_set_format (&this->priv->v_info, GST_VIDEO_FORMAT_RGBA,
         size.width(), size.height());
+    gst_clear_object (&this->priv->pool);
 
-    if (this->priv->gl_params) {
-      GstGLVideoAllocationParams *gl_vid_params = (GstGLVideoAllocationParams *) this->priv->gl_params;
-      if (GST_VIDEO_INFO_WIDTH (gl_vid_params->v_info) != source->width()
-            || GST_VIDEO_INFO_HEIGHT (gl_vid_params->v_info) != source->height())
-        this->priv->gl_params = NULL;
-      gst_clear_buffer (&this->priv->buffer);
-    }
+    GST_LOG ("resolution change, skipping frames until we have a new pool");
+    g_cond_signal (&this->priv->update_cond);
+    g_mutex_unlock (&this->priv->lock);
+    return;
   }
 
-  if (!this->priv->gl_params) {
-    this->priv->gl_params = (GstGLAllocationParams *)
-        gst_gl_video_allocation_params_new (this->priv->context, NULL,
-        &this->priv->v_info, 0, NULL, GST_GL_TEXTURE_TARGET_2D, GST_GL_RGBA);
-  }
-
-  if (!this->priv->buffer) {
-    GstGLMemory *gl_mem =
-        (GstGLMemory *) gst_gl_base_memory_alloc (this->priv->gl_allocator,
-        this->priv->gl_params);
-    this->priv->buffer = gst_buffer_new ();
-    gst_buffer_append_memory (this->priv->buffer, (GstMemory *) gl_mem);
+  GstFlowReturn ret = gst_buffer_pool_acquire_buffer (this->priv->pool,
+      &this->priv->buffer, NULL);
+  if (ret == GST_FLOW_FLUSHING) {
+    g_mutex_unlock (&this->priv->lock);
+    return;
+  } else if (ret != GST_FLOW_OK) {
+    GST_WARNING ("failed to acquire buffer");
+    g_mutex_unlock (&this->priv->lock);
+    return;
   }
 
   if (!gst_video_frame_map (&this->priv->mapped_frame, &this->priv->v_info,
         this->priv->buffer, (GstMapFlags) (GST_MAP_WRITE | GST_MAP_GL))) {
     GST_WARNING ("failed map video frame");
     gst_clear_buffer (&this->priv->buffer);
+    g_mutex_unlock (&this->priv->lock);
     return;
   }
 
@@ -424,7 +416,7 @@ qt6_gl_window_is_scenegraph_initialized (Qt6GLWindow * qt6_gl_window)
 }
 
 GstBuffer *
-qt6_gl_window_take_buffer (Qt6GLWindow * qt6_gl_window, GstCaps ** updated_caps)
+qt6_gl_window_take_buffer (Qt6GLWindow * qt6_gl_window, gboolean * updated_caps)
 {
   g_return_val_if_fail (qt6_gl_window != NULL, FALSE);
   g_return_val_if_fail (qt6_gl_window->priv->initted, FALSE);
@@ -438,18 +430,16 @@ qt6_gl_window_take_buffer (Qt6GLWindow * qt6_gl_window, GstCaps ** updated_caps)
     return NULL;
   }
 
-  while (!qt6_gl_window->priv->produced_buffer && qt6_gl_window->priv->result)
+  while (!qt6_gl_window->priv->produced_buffer && qt6_gl_window->priv->result
+      && !qt6_gl_window->priv->new_caps)
     g_cond_wait (&qt6_gl_window->priv->update_cond, &qt6_gl_window->priv->lock);
 
   ret = qt6_gl_window->priv->produced_buffer;
   qt6_gl_window->priv->produced_buffer = NULL;
 
-  if (qt6_gl_window->priv->new_caps) {
-    *updated_caps = gst_video_info_to_caps (&qt6_gl_window->priv->v_info);
-    gst_caps_set_features (*updated_caps, 0,
-        gst_caps_features_new_single_static_str
-        (GST_CAPS_FEATURE_MEMORY_GL_MEMORY));
+  if (!ret && qt6_gl_window->priv->new_caps) {
     qt6_gl_window->priv->new_caps = FALSE;
+    *updated_caps = TRUE;
   }
 
   g_mutex_unlock (&qt6_gl_window->priv->lock);
@@ -493,3 +483,13 @@ qt6_gl_window_unlock_stop(Qt6GLWindow* qt6_gl_window)
 
   g_mutex_unlock(&qt6_gl_window->priv->lock);
 }
+
+void
+qt6_gl_window_set_pool (Qt6GLWindow * qt6_gl_window, GstBufferPool * pool)
+{
+  g_mutex_lock(&qt6_gl_window->priv->lock);
+  if (qt6_gl_window->priv->pool)
+    gst_object_unref (qt6_gl_window->priv->pool);
+  qt6_gl_window->priv->pool = pool;
+  g_mutex_unlock(&qt6_gl_window->priv->lock);
+}

subprojects/gst-plugins-good/ext/qt6/qt6glwindow.h

@@ -55,7 +55,7 @@ private:
 
 extern "C"
 {
-GstBuffer *     qt6_gl_window_take_buffer (Qt6GLWindow * qt6_window, GstCaps ** updated_caps);
+GstBuffer *     qt6_gl_window_take_buffer (Qt6GLWindow * qt6_window, gboolean * updated_caps);
 GstGLContext *  qt6_gl_window_get_qt_context (Qt6GLWindow * qt6_window);
 GstGLContext *  qt6_gl_window_get_context (Qt6GLWindow * qt6_window);
 gboolean        qt6_gl_window_set_context (Qt6GLWindow * qt6_window, GstGLContext * context);
@@ -64,6 +64,7 @@ gboolean        qt6_gl_window_is_scenegraph_initialized (Qt6GLWindow * qt6_windo
 void            qt6_gl_window_use_default_fbo (Qt6GLWindow * qt6_window, gboolean useDefaultFbo);
 void            qt6_gl_window_unlock(Qt6GLWindow* qt6_window);
 void            qt6_gl_window_unlock_stop(Qt6GLWindow* qt6_window);
+void            qt6_gl_window_set_pool (Qt6GLWindow * qt6_window, GstBufferPool * pool);
 }
 
 #endif /* __QT6_GL_WINDOW_H__ */