omxvideoenc: implement decide_allocation

Increase the number of output buffers by the number of buffers requested
downstream.
Prevent buffers starvation if downstream is going to use dynamic buffer
mode on its input.

https://bugzilla.gnome.org/show_bug.cgi?id=795746

1 files changed, 42 insertions, 5 deletions

diff --git a/omx/gstomxvideoenc.c b/omx/gstomxvideoenc.c
index faba38e..1a630c4 100644
--- a/omx/gstomxvideoenc.c
+++ b/omx/gstomxvideoenc.c
@@ -226,6 +226,8 @@ static gboolean gst_omx_video_enc_propose_allocation (GstVideoEncoder * encoder,
     GstQuery * query);
 static GstCaps *gst_omx_video_enc_getcaps (GstVideoEncoder * encoder,
     GstCaps * filter);
+static gboolean gst_omx_video_enc_decide_allocation (GstVideoEncoder * encoder,
+    GstQuery * query);
 
 static GstFlowReturn gst_omx_video_enc_drain (GstOMXVideoEnc * self);
 
@@ -481,6 +483,8 @@ gst_omx_video_enc_class_init (GstOMXVideoEncClass * klass)
   video_encoder_class->propose_allocation =
       GST_DEBUG_FUNCPTR (gst_omx_video_enc_propose_allocation);
   video_encoder_class->getcaps = GST_DEBUG_FUNCPTR (gst_omx_video_enc_getcaps);
+  video_encoder_class->decide_allocation =
+      GST_DEBUG_FUNCPTR (gst_omx_video_enc_decide_allocation);
 
   klass->cdata.type = GST_OMX_COMPONENT_TYPE_FILTER;
   klass->cdata.default_sink_template_caps = "video/x-raw, "
@@ -1372,11 +1376,18 @@ static gboolean
 gst_omx_video_enc_ensure_nb_out_buffers (GstOMXVideoEnc * self)
 {
   GstOMXVideoEncClass *klass = GST_OMX_VIDEO_ENC_GET_CLASS (self);
+  guint extra = 0;
 
-  if ((klass->cdata.hacks & GST_OMX_HACK_ENSURE_BUFFER_COUNT_ACTUAL)) {
-    if (!gst_omx_port_ensure_buffer_count_actual (self->enc_out_port))
-      return FALSE;
-  }
+  if (!(klass->cdata.hacks & GST_OMX_HACK_ENSURE_BUFFER_COUNT_ACTUAL))
+    return TRUE;
+
+  /* If dowstream tell us how many buffers it needs allocate as many extra buffers so we won't starve
+   * if it keeps them downstream (like when using dynamic mode). */
+  if (self->nb_downstream_buffers)
+    extra = self->nb_downstream_buffers;
+
+  if (!gst_omx_port_ensure_buffer_count_actual (self->enc_out_port, extra))
+    return FALSE;
 
   return TRUE;
 }
@@ -1641,6 +1652,7 @@ gst_omx_video_enc_start (GstVideoEncoder * encoder)
 
   self->last_upstream_ts = 0;
   self->downstream_flow_ret = GST_FLOW_OK;
+  self->nb_downstream_buffers = 0;
 
   return TRUE;
 }
@@ -1883,7 +1895,7 @@ gst_omx_video_enc_ensure_nb_in_buffers (GstOMXVideoEnc * self)
   GstOMXVideoEncClass *klass = GST_OMX_VIDEO_ENC_GET_CLASS (self);
 
   if ((klass->cdata.hacks & GST_OMX_HACK_ENSURE_BUFFER_COUNT_ACTUAL)) {
-    if (!gst_omx_port_ensure_buffer_count_actual (self->enc_in_port))
+    if (!gst_omx_port_ensure_buffer_count_actual (self->enc_in_port, 0))
       return FALSE;
   }
 
@@ -3030,3 +3042,28 @@ gst_omx_video_enc_getcaps (GstVideoEncoder * encoder, GstCaps * filter)
 
   return ret;
 }
+
+static gboolean
+gst_omx_video_enc_decide_allocation (GstVideoEncoder * encoder,
+    GstQuery * query)
+{
+  GstOMXVideoEnc *self = GST_OMX_VIDEO_ENC (encoder);
+  guint min = 1;
+
+  if (!GST_VIDEO_ENCODER_CLASS
+      (gst_omx_video_enc_parent_class)->decide_allocation (encoder, query))
+    return FALSE;
+
+  if (gst_query_get_n_allocation_pools (query)) {
+    gst_query_parse_nth_allocation_pool (query, 0, NULL, NULL, &min, NULL);
+    GST_DEBUG_OBJECT (self,
+        "Downstream requested %d buffers, adjust number of output buffers accordingly",
+        min);
+  } else {
+    GST_DEBUG_OBJECT (self, "Downstream didn't set any allocation pool info");
+  }
+
+  self->nb_downstream_buffers = min;
+
+  return TRUE;
+}