Simplify default temporal layers.

webrtc/modules/video_coding/codecs/vp8/default_temporal_layers.h

 /* Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */
 /*
 * This file defines classes for doing temporal layers with VP8.
 */
 #ifndef WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_DEFAULT_TEMPORAL_LAYERS_H_
 #define WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_DEFAULT_TEMPORAL_LAYERS_H_
 
 #include <vector>
 
 #include "webrtc/modules/video_coding/codecs/vp8/temporal_layers.h"
 
 #include "webrtc/base/optional.h"
 
 namespace webrtc {
 
+enum TemporalBufferUsage {
+  kNone = 0,
+  kReference = 1,
+  kUpdate = 2,
+  kReferenceAndUpdate = kReference | kUpdate,
+};
+enum TemporalFlags { kLayerSync = 1, kFreezeEntropy = 2 };
+
+struct TemporalReferences {
+  TemporalReferences(TemporalBufferUsage last,
+                     TemporalBufferUsage golden,
+                     TemporalBufferUsage arf);
+  TemporalReferences(TemporalBufferUsage last,
+                     TemporalBufferUsage golden,
+                     TemporalBufferUsage arf,
+                     int extra_flags);
+
+  const bool reference_last;

[pbos-webrtc, 2017/03/17 18:03:44]

The idea is that these bools here are easier to understand and translate to
hardware encoder parameters. They would have to do conversion similar to
::EncodeFlags() in the .cc file.

+  const bool update_last;
+  const bool reference_golden;
+  const bool update_golden;

[brandtr, 2017/03/21 12:20:09]

I like these names instead of "buffer 0, 1, 2". What would the benefit of naming
them with numbers be? That we can generalize this to other codecs later on?

[pbos-webrtc, 2017/03/21 17:37:46]

Potentially that the buffer used doesn't really matter, but I think I like
keeping them too.

+  const bool reference_arf;
+  const bool update_arf;
+  const bool layer_sync;
+  const bool freeze_entropy;
+
+ private:
+  TemporalReferences(TemporalBufferUsage last,
+                     TemporalBufferUsage golden,
+                     TemporalBufferUsage arf,
+                     bool layer_sync,
+                     bool freeze_entropy);
+};
+
 class DefaultTemporalLayers : public TemporalLayers {
  public:
   DefaultTemporalLayers(int number_of_temporal_layers,
                         uint8_t initial_tl0_pic_idx);
   virtual ~DefaultTemporalLayers() {}
 
   // Returns the recommended VP8 encode flags needed. May refresh the decoder
   // and/or update the reference buffers.
   int EncodeFlags(uint32_t timestamp) override;
 
   // Update state based on new bitrate target and incoming framerate.
   // Returns the bitrate allocation for the active temporal layers.
   std::vector<uint32_t> OnRatesUpdated(int bitrate_kbps,
                                        int max_bitrate_kbps,
                                        int framerate) override;
 
   bool UpdateConfiguration(vpx_codec_enc_cfg_t* cfg) override;
 
   void PopulateCodecSpecific(bool base_layer_sync,
                              CodecSpecificInfoVP8* vp8_info,
                              uint32_t timestamp) override;
 
   void FrameEncoded(unsigned int size, uint32_t timestamp, int qp) override {}
 
   int CurrentLayerId() const override;
 
  private:
-  enum TemporalReferences {
-    // For 1 layer case: reference all (last, golden, and alt ref), but only
-    // update last.
-    kTemporalUpdateLastRefAll = 12,
-    // First base layer frame for 3 temporal layers, which updates last and
-    // golden with alt ref dependency.
-    kTemporalUpdateLastAndGoldenRefAltRef = 11,
-    // First enhancement layer with alt ref dependency.
-    kTemporalUpdateGoldenRefAltRef = 10,
-    // First enhancement layer with alt ref dependency.
-    kTemporalUpdateGoldenWithoutDependencyRefAltRef = 9,
-    // Base layer with alt ref dependency.
-    kTemporalUpdateLastRefAltRef = 8,
-    // Highest enhacement layer without dependency on golden with alt ref
-    // dependency.
-    kTemporalUpdateNoneNoRefGoldenRefAltRef = 7,
-    // Second layer and last frame in cycle, for 2 layers.
-    kTemporalUpdateNoneNoRefAltref = 6,
-    // Highest enhancement layer.
-    kTemporalUpdateNone = 5,
-    // Second enhancement layer.
-    kTemporalUpdateAltref = 4,
-    // Second enhancement layer without dependency on previous frames in
-    // the second enhancement layer.
-    kTemporalUpdateAltrefWithoutDependency = 3,
-    // First enhancement layer.
-    kTemporalUpdateGolden = 2,
-    // First enhancement layer without dependency on previous frames in
-    // the first enhancement layer.
-    kTemporalUpdateGoldenWithoutDependency = 1,
-    // Base layer.
-    kTemporalUpdateLast = 0,
-  };
-  enum { kMaxTemporalPattern = 16 };
+  const size_t num_layers_;
+  const std::vector<unsigned int> temporal_ids_;
+  const std::vector<TemporalReferences> temporal_pattern_;
 
-  const int number_of_temporal_layers_;
-  int temporal_ids_length_;
-  int temporal_ids_[kMaxTemporalPattern];
-  int temporal_pattern_length_;
-  TemporalReferences temporal_pattern_[kMaxTemporalPattern];
   uint8_t tl0_pic_idx_;
   uint8_t pattern_idx_;
   uint32_t timestamp_;
   bool last_base_layer_sync_;
   rtc::Optional<std::vector<uint32_t>> new_bitrates_kbps_;
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_DEFAULT_TEMPORAL_LAYERS_H_