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vp8_frame_config.h (3736B)

      1 /*
      2 *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
      3 *
      4 *  Use of this source code is governed by a BSD-style license
      5 *  that can be found in the LICENSE file in the root of the source
      6 *  tree. An additional intellectual property rights grant can be found
      7 *  in the file PATENTS.  All contributing project authors may
      8 *  be found in the AUTHORS file in the root of the source tree.
      9 */
     10 
     11 #ifndef API_VIDEO_CODECS_VP8_FRAME_CONFIG_H_
     12 #define API_VIDEO_CODECS_VP8_FRAME_CONFIG_H_
     13 
     14 #include <stdint.h>
     15 
     16 namespace webrtc {
     17 
     18 // Configuration of a VP8 frame - which buffers are to be referenced
     19 // by it, which buffers should be updated, etc.
     20 struct Vp8FrameConfig {
     21  static Vp8FrameConfig GetIntraFrameConfig() {
     22    Vp8FrameConfig frame_config = Vp8FrameConfig(
     23        BufferFlags::kUpdate, BufferFlags::kUpdate, BufferFlags::kUpdate);
     24    frame_config.packetizer_temporal_idx = 0;
     25    return frame_config;
     26  }
     27 
     28  enum BufferFlags : int {
     29    kNone = 0,
     30    kReference = 1,
     31    kUpdate = 2,
     32    kReferenceAndUpdate = kReference | kUpdate,
     33  };
     34 
     35  enum FreezeEntropy { kFreezeEntropy };
     36 
     37  // Defined bit-maskable reference to the three buffers available in VP8.
     38  enum class Vp8BufferReference : uint8_t {
     39    kNone = 0,
     40    kLast = 1,
     41    kGolden = 2,
     42    kAltref = 4
     43  };
     44 
     45  Vp8FrameConfig();
     46 
     47  Vp8FrameConfig(BufferFlags last, BufferFlags golden, BufferFlags arf);
     48  Vp8FrameConfig(BufferFlags last,
     49                 BufferFlags golden,
     50                 BufferFlags arf,
     51                 FreezeEntropy);
     52 
     53  enum class Buffer : int { kLast = 0, kGolden = 1, kArf = 2, kCount };
     54 
     55  bool References(Buffer buffer) const;
     56 
     57  bool Updates(Buffer buffer) const;
     58 
     59  bool IntraFrame() const {
     60    // Intra frames do not reference any buffers, and update all buffers.
     61    return last_buffer_flags == kUpdate && golden_buffer_flags == kUpdate &&
     62           arf_buffer_flags == kUpdate;
     63  }
     64 
     65  bool drop_frame;
     66  BufferFlags last_buffer_flags;
     67  BufferFlags golden_buffer_flags;
     68  BufferFlags arf_buffer_flags;
     69 
     70  // The encoder layer ID is used to utilize the correct bitrate allocator
     71  // inside the encoder. It does not control references nor determine which
     72  // "actual" temporal layer this is. The packetizer temporal index determines
     73  // which layer the encoded frame should be packetized into.
     74  // Normally these are the same, but current temporal-layer strategies for
     75  // screenshare use one bitrate allocator for all layers, but attempt to
     76  // packetize / utilize references to split a stream into multiple layers,
     77  // with different quantizer settings, to hit target bitrate.
     78  // TODO(sprang): Screenshare layers are being reconsidered at the time of
     79  // writing, we might be able to remove this distinction, and have a temporal
     80  // layer imply both (the normal case).
     81  int encoder_layer_id;
     82  // TODO(eladalon/sprang): Move out of this class.
     83  int packetizer_temporal_idx;
     84 
     85  // TODO(eladalon/sprang): Move out of this class.
     86  bool layer_sync;
     87 
     88  bool freeze_entropy;
     89 
     90  // Indicates in which order the encoder should search the reference buffers
     91  // when doing motion prediction. Set to kNone to use unspecified order. Any
     92  // buffer indicated here must not have the corresponding no_ref bit set.
     93  // If all three buffers can be reference, the one not listed here should be
     94  // searched last.
     95  Vp8BufferReference first_reference;
     96  Vp8BufferReference second_reference;
     97 
     98  // Whether this frame is eligible for retransmission.
     99  bool retransmission_allowed;
    100 
    101 private:
    102  Vp8FrameConfig(BufferFlags last,
    103                 BufferFlags golden,
    104                 BufferFlags arf,
    105                 bool freeze_entropy);
    106 };
    107 
    108 }  // namespace webrtc
    109 
    110 #endif  // API_VIDEO_CODECS_VP8_FRAME_CONFIG_H_