Work on flexible mode and screen sharing.

webrtc/modules/video_coding/codecs/vp9/vp9_impl.h

Index: webrtc/modules/video_coding/codecs/vp9/vp9_impl.h
diff --git a/webrtc/modules/video_coding/codecs/vp9/vp9_impl.h b/webrtc/modules/video_coding/codecs/vp9/vp9_impl.h
index f9c123079e16b55d892ac8baba214d36cfc0b33e..8f18242d26cb181ccb29f0f9339a503c072b456b 100644
--- a/webrtc/modules/video_coding/codecs/vp9/vp9_impl.h
+++ b/webrtc/modules/video_coding/codecs/vp9/vp9_impl.h
@@ -21,6 +21,8 @@
 
 namespace webrtc {
 
+class ScreenshareLayersVP9;
+
 class VP9EncoderImpl : public VP9Encoder {
  public:
   VP9EncoderImpl();
@@ -45,6 +47,20 @@ class VP9EncoderImpl : public VP9Encoder {
 
   void OnDroppedFrame() override {}
 
+  struct LayerFrameRefSettings {
+    int8_t upd_buf = -1;   // -1 - no update,    0..7 - update buffer 0..7
+    int8_t ref_buf1 = -1;  // -1 - no reference, 0..7 - reference buffer 0..7
+    int8_t ref_buf2 = -1;  // -1 - no reference, 0..7 - reference buffer 0..7
+    int8_t ref_buf3 = -1;  // -1 - no reference, 0..7 - reference buffer 0..7
+  };
+
+  struct SuperFrameRefSettings {
+    LayerFrameRefSettings layer[kMaxVp9NumberOfSpatialLayers];
+    uint8_t start_layer = 0;
+    uint8_t stop_layer = 0;

[stefan-webrtc, 2015/10/28 13:59:05]

What is a start and a stop layer?

[philipel1, 2015/10/29 14:49:27]

The first/last spatial layer to be encoded. Added comments to the code.

+    bool is_keyframe = false;
+  };
+
  private:
   // Determine number of encoder threads to use.
   int NumberOfThreads(int width, int height, int number_of_cores);
@@ -58,6 +74,17 @@ class VP9EncoderImpl : public VP9Encoder {
 
   bool SetSvcRates();
 
+  /*
+   * Used for flexible mode to set the flags and buffer references used
+   * by the encoder. Also calculates the references used by the RTP
+   * packetizer.
+   *
+   * Has to be called for every frame (keyframes included) to update the
+   * state used to calculate references.
+   */

[stefan-webrtc, 2015/10/28 13:59:04]

C++ comments please

[philipel1, 2015/10/29 14:49:27]

Done.

+  vpx_svc_ref_frame_config GenerateRefsAndFlags(
+      const SuperFrameRefSettings& settings);
+
   virtual int GetEncodedLayerFrame(const vpx_codec_cx_pkt* pkt);
 
   // Callback function for outputting packets per spatial layer.
@@ -88,9 +115,17 @@ class VP9EncoderImpl : public VP9Encoder {
   GofInfoVP9 gof_;       // Contains each frame's temporal information for
                          // non-flexible mode.
   uint8_t tl0_pic_idx_;  // Only used in non-flexible mode.
-  size_t gof_idx_;       // Only used in non-flexible mode.
+  size_t frames_since_kf_;
   uint8_t num_temporal_layers_;
   uint8_t num_spatial_layers_;
+
+  // Used for flexible mode.
+  bool is_flexible_mode_;
+  int64_t buf_upd_at_frame_[kNumVp9Buffers];

[stefan-webrtc, 2015/10/28 13:59:04]

I'd prefer a longer variable name here.

[philipel1, 2015/10/29 14:49:27]

Done.

+  int64_t frames_encoded_;
+  uint8_t num_ref_pics_[kMaxVp9NumberOfSpatialLayers];
+  uint16_t p_diff_[kMaxVp9NumberOfSpatialLayers][kMaxVp9RefPics];
+  rtc::scoped_ptr<ScreenshareLayersVP9> spatial_layer_;
 };