Add class to gather VP9 level stats.

See http://www.webmproject.org/vp9/profiles/ for more information
on VP9 levels.

BUG=https://bugs.chromium.org/p/webm/issues/detail?id=1188

Change-Id: I91448069bbd4740106a159014db6935365af75ca

common/vp9_level_stats.h

@@ -0,0 +1,184 @@
+// Copyright (c) 2016 The WebM 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.
+#ifndef LIBWEBM_COMMON_VP9_LEVEL_STATS_H_
+#define LIBWEBM_COMMON_VP9_LEVEL_STATS_H_
+
+#include <limits>
+#include <queue>
+#include <utility>
+
+#include "common/vp9_header_parser.h"
+
+namespace vp9_parser {
+
+const int kMaxVp9RefFrames = 8;
+
+// Defined VP9 levels. See http://www.webmproject.org/vp9/profiles/ for
+// detailed information on VP9 levels.
+const int kNumVp9Levels = 14;
+enum Vp9Level {
+  LEVEL_UNKNOWN = 0,
+  LEVEL_1 = 10,
+  LEVEL_1_1 = 11,
+  LEVEL_2 = 20,
+  LEVEL_2_1 = 21,
+  LEVEL_3 = 30,
+  LEVEL_3_1 = 31,
+  LEVEL_4 = 40,
+  LEVEL_4_1 = 41,
+  LEVEL_5 = 50,
+  LEVEL_5_1 = 51,
+  LEVEL_5_2 = 52,
+  LEVEL_6 = 60,
+  LEVEL_6_1 = 61,
+  LEVEL_6_2 = 62
+};
+
+struct Vp9LevelRow {
+  Vp9LevelRow() = default;
+  ~Vp9LevelRow() = default;
+  Vp9LevelRow(Vp9LevelRow&& other) = default;
+  Vp9LevelRow(const Vp9LevelRow& other) = default;
+  Vp9LevelRow& operator=(Vp9LevelRow&& other) = delete;
+  Vp9LevelRow& operator=(const Vp9LevelRow& other) = delete;
+
+  Vp9Level level;
+  int64_t max_luma_sample_rate;
+  int64_t max_luma_picture_size;
+  double average_bitrate;
+  double max_cpb_size;
+  double compresion_ratio;
+  int max_tiles;
+  int min_altref_distance;
+  int max_ref_frames;
+};
+
+// Class to determine the VP9 level of a VP9 bitstream.
+class Vp9LevelStats {
+ public:
+  static const Vp9LevelRow Vp9LevelTable[kNumVp9Levels];
+
+  Vp9LevelStats()
+      : frames(0),
+        displayed_frames(0),
+        start_ns_(-1),
+        end_ns_(-1),
+        duration_ns_(-1),
+        max_luma_picture_size_(0),
+        current_luma_size_(0),
+        max_luma_size_(0),
+        max_luma_end_ns_(0),
+        max_frames_in_one_second_(0),
+        first_altref(true),
+        frames_since_last_altref(0),
+        minimum_altref_distance(std::numeric_limits<int>::max()),
+        min_altref_end_ns(0),
+        max_cpb_window_size_(0),
+        max_cpb_window_end_ns_(0),
+        current_cpb_size_(0),
+        max_cpb_size_(0),
+        max_cpb_start_ns_(0),
+        max_cpb_end_ns_(0),
+        total_compressed_size_(0),
+        total_uncompressed_bits_(0),
+        frames_refreshed_(0),
+        max_frames_refreshed_(0),
+        max_column_tiles_(0) {}
+
+  ~Vp9LevelStats() = default;
+  Vp9LevelStats(Vp9LevelStats&& other) = delete;
+  Vp9LevelStats(const Vp9LevelStats& other) = delete;
+  Vp9LevelStats& operator=(Vp9LevelStats&& other) = delete;
+  Vp9LevelStats& operator=(const Vp9LevelStats& other) = delete;
+
+  // Collects stats on a VP9 frame. The frame must already be parsed by
+  // |parser|. |time_ns| is the start time of the frame in nanoseconds.
+  void AddFrame(const Vp9HeaderParser& parser, int64_t time_ns);
+
+  // Returns the current VP9 level. All of the video frames should have been
+  // processed with AddFrame before calling this function.
+  Vp9Level GetLevel() const;
+
+  // Returns the maximum luma samples (pixels) per second. The Alt-Ref frames
+  // are taken into account, therefore this number may be larger than the
+  // display luma samples per second
+  int64_t GetMaxLumaSampleRate() const;
+
+  // The maximum frame size (width * height) in samples.
+  int64_t GetMaxLumaPictureSize() const;
+
+  // The average bitrate of the video in kbps.
+  double GetAverageBitRate() const;
+
+  // The largest data size for any 4 consecutive frames in kilobits.
+  double GetMaxCpbSize() const;
+
+  // The ratio of total bytes decompressed over total bytes compressed.
+  double GetCompressionRatio() const;
+
+  // The maximum number of VP9 column tiles.
+  int GetMaxColumnTiles() const;
+
+  // The minimum distance in frames between two consecutive alternate reference
+  // frames.
+  int GetMinimumAltrefDistance() const;
+
+  // The maximum number of reference frames that had to be stored.
+  int GetMaxReferenceFrames() const;
+
+  // Sets the duration of the video stream in nanoseconds. If the duration is
+  // not explictly set by this function then this class will use end - start
+  // as the duration.
+  void set_duration(int64_t time_ns) { duration_ns_ = time_ns; }
+
+ private:
+  int frames;
+  int displayed_frames;
+
+  int64_t start_ns_;
+  int64_t end_ns_;
+  int64_t duration_ns_;
+
+  int64_t max_luma_picture_size_;
+
+  // This is used to calculate the maximum number of luma samples per second.
+  // The first value is the luma picture size and the second value is the time
+  // in nanoseconds of one frame.
+  std::queue<std::pair<int64_t, int64_t>> luma_window_;
+  int64_t current_luma_size_;
+  int64_t max_luma_size_;
+  int64_t max_luma_end_ns_;
+  size_t max_frames_in_one_second_;
+
+  bool first_altref;
+  int frames_since_last_altref;
+  int minimum_altref_distance;
+  int64_t min_altref_end_ns;
+
+  // This is used to calculate the maximum number of compressed bytes for four
+  // consecutive frames. The first value is the compressed frame size and the
+  // second value is the time in nanoseconds of one frame.
+  std::queue<std::pair<int64_t, int64_t>> cpb_window_;
+  int64_t max_cpb_window_size_;
+  int64_t max_cpb_window_end_ns_;
+  int64_t current_cpb_size_;
+  int64_t max_cpb_size_;
+  int64_t max_cpb_start_ns_;
+  int64_t max_cpb_end_ns_;
+
+  int64_t total_compressed_size_;
+  int64_t total_uncompressed_bits_;
+  int frames_refreshed_;
+  int max_frames_refreshed_;
+
+  int max_column_tiles_;
+};
+
+}  // namespace vp9_parser
+
+#endif  // LIBWEBM_COMMON_VP9_LEVEL_STATS_H_