From 5add956727e086a285a725d1558fe03d3d862053 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Sat, 5 May 2018 12:16:35 +0200
Subject: [PATCH] glmixer: Move frame/texture mapping/unmapping into
 prepare/clean_frame

Previously we assumed that the texture ID is going to be valid even
after unmapping the frame, as it was immediately unmapped before even
being used. Now we only unmap once we're done with the texture.
---
 ext/gl/gstglmixer.c | 103 ++++++++++++++++++++++++++++++----------------------
 1 file changed, 59 insertions(+), 44 deletions(-)

diff --git a/ext/gl/gstglmixer.c b/ext/gl/gstglmixer.c
index 2ea099e..327da54 100644
--- a/ext/gl/gstglmixer.c
+++ b/ext/gl/gstglmixer.c
@@ -38,6 +38,10 @@ static void gst_gl_mixer_pad_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec);
 static void gst_gl_mixer_pad_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec);
+static gboolean gst_gl_mixer_pad_prepare_frame (GstVideoAggregatorPad * vpad,
+    GstVideoAggregator * vagg);
+static void gst_gl_mixer_pad_clean_frame (GstVideoAggregatorPad * vpad,
+    GstVideoAggregator * vagg);
 
 enum
 {
@@ -69,8 +73,8 @@ gst_gl_mixer_pad_class_init (GstGLMixerPadClass * klass)
   gobject_class->get_property = gst_gl_mixer_pad_get_property;
 
   vaggpad_class->set_info = NULL;
-  vaggpad_class->prepare_frame = NULL;
-  vaggpad_class->clean_frame = NULL;
+  vaggpad_class->prepare_frame = gst_gl_mixer_pad_prepare_frame;
+  vaggpad_class->clean_frame = gst_gl_mixer_pad_clean_frame;
 }
 
 static void
@@ -96,6 +100,59 @@ gst_gl_mixer_pad_set_property (GObject * object, guint prop_id,
 }
 
 static gboolean
+gst_gl_mixer_pad_prepare_frame (GstVideoAggregatorPad * vpad,
+    GstVideoAggregator * vagg)
+{
+  GstGLMixerPad *pad = GST_GL_MIXER_PAD (vpad);
+  GstGLMixer *mix = GST_GL_MIXER (vagg);
+
+  pad->current_texture = 0;
+  vpad->aggregated_frame = NULL;
+
+  if (vpad->buffer != NULL) {
+    GstVideoInfo gl_info;
+    GstVideoFrame aggregated_frame;
+    GstGLSyncMeta *sync_meta;
+
+    gst_video_info_set_format (&gl_info,
+        GST_VIDEO_FORMAT_RGBA,
+        GST_VIDEO_INFO_WIDTH (&vpad->info),
+        GST_VIDEO_INFO_HEIGHT (&vpad->info));
+
+    sync_meta = gst_buffer_get_gl_sync_meta (vpad->buffer);
+    if (sync_meta)
+      gst_gl_sync_meta_wait (sync_meta, GST_GL_BASE_MIXER (mix)->context);
+
+    if (!gst_video_frame_map (&aggregated_frame, &gl_info, vpad->buffer,
+            GST_MAP_READ | GST_MAP_GL)) {
+      GST_ERROR_OBJECT (pad, "Failed to map input frame");
+      return FALSE;
+    }
+
+    pad->current_texture = *(guint *) aggregated_frame.data[0];
+
+    vpad->aggregated_frame = g_slice_new0 (GstVideoFrame);
+    *vpad->aggregated_frame = aggregated_frame;
+  }
+
+  return TRUE;
+}
+
+static void
+gst_gl_mixer_pad_clean_frame (GstVideoAggregatorPad * vpad,
+    GstVideoAggregator * vagg)
+{
+  GstGLMixerPad *pad = GST_GL_MIXER_PAD (vpad);
+
+  pad->current_texture = 0;
+  if (vpad->aggregated_frame) {
+    gst_video_frame_unmap (vpad->aggregated_frame);
+    g_slice_free (GstVideoFrame, vpad->aggregated_frame);
+    vpad->aggregated_frame = NULL;
+  }
+}
+
+static gboolean
 _negotiated_caps (GstAggregator * agg, GstCaps * caps)
 {
   GstGLMixer *mix = GST_GL_MIXER (agg);
@@ -561,42 +618,6 @@ context_error:
   }
 }
 
-static gboolean
-gst_gl_mixer_upload_frames (GstElement * element, GstPad * sink_pad,
-    gpointer user_data)
-{
-  GstVideoAggregatorPad *vaggpad = GST_VIDEO_AGGREGATOR_PAD (sink_pad);
-  GstGLMixerPad *pad = GST_GL_MIXER_PAD (sink_pad);
-  GstGLMixer *mix = GST_GL_MIXER (element);
-
-  pad->current_texture = 0;
-  if (vaggpad->buffer != NULL) {
-    GstVideoInfo gl_info;
-    GstVideoFrame gl_frame;
-    GstGLSyncMeta *sync_meta;
-
-    gst_video_info_set_format (&gl_info,
-        GST_VIDEO_FORMAT_RGBA,
-        GST_VIDEO_INFO_WIDTH (&vaggpad->info),
-        GST_VIDEO_INFO_HEIGHT (&vaggpad->info));
-
-    sync_meta = gst_buffer_get_gl_sync_meta (vaggpad->buffer);
-    if (sync_meta)
-      gst_gl_sync_meta_wait (sync_meta, GST_GL_BASE_MIXER (mix)->context);
-
-    if (!gst_video_frame_map (&gl_frame, &gl_info, vaggpad->buffer,
-            GST_MAP_READ | GST_MAP_GL)) {
-      GST_ERROR_OBJECT (pad, "Failed to map input frame");
-      return FALSE;
-    }
-
-    pad->current_texture = *(guint *) gl_frame.data[0];
-    gst_video_frame_unmap (&gl_frame);
-  }
-
-  return TRUE;
-}
-
 gboolean
 gst_gl_mixer_process_textures (GstGLMixer * mix, GstBuffer * outbuf)
 {
@@ -616,12 +637,6 @@ gst_gl_mixer_process_textures (GstGLMixer * mix, GstBuffer * outbuf)
 
   out_tex = (GstGLMemory *) out_frame.map[0].memory;
 
-  if (!gst_element_foreach_sink_pad (GST_ELEMENT_CAST (mix),
-          gst_gl_mixer_upload_frames, NULL)) {
-    res = FALSE;
-    goto out;
-  }
-
   g_mutex_lock (&priv->gl_resource_lock);
   if (!priv->gl_resource_ready)
     g_cond_wait (&priv->gl_resource_cond, &priv->gl_resource_lock);
-- 
2.7.4