packet_buffer.h - mozsearch

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/*

 *  Copyright (c) 2012 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.

*/

#ifndef MODULES_AUDIO_CODING_NETEQ_PACKET_BUFFER_H_

#define MODULES_AUDIO_CODING_NETEQ_PACKET_BUFFER_H_

#include "absl/types/optional.h"

#include "modules/audio_coding/neteq/decoder_database.h"

#include "modules/audio_coding/neteq/packet.h"

#include "modules/include/module_common_types_public.h"  // IsNewerTimestamp

namespace webrtc {

class DecoderDatabase;

class StatisticsCalculator;

class TickTimer;

// This is the actual buffer holding the packets before decoding.

class PacketBuffer {

 public:

  enum BufferReturnCodes {

    kOK = 0,

    kFlushed,

    kNotFound,

    kBufferEmpty,

    kInvalidPacket,

    kInvalidPointer

};

  // Constructor creates a buffer which can hold a maximum of

  // `max_number_of_packets` packets.

  PacketBuffer(size_t max_number_of_packets,

               const TickTimer* tick_timer,

               StatisticsCalculator* stats);

  // Deletes all packets in the buffer before destroying the buffer.

  virtual ~PacketBuffer();

  PacketBuffer(const PacketBuffer&) = delete;

  PacketBuffer& operator=(const PacketBuffer&) = delete;

  // Flushes the buffer and deletes all packets in it.

  virtual void Flush();

  // Returns true for an empty buffer.

  virtual bool Empty() const;

  // Inserts `packet` into the buffer. The buffer will take over ownership of

  // the packet object.

  // Returns PacketBuffer::kOK on success, PacketBuffer::kFlushed if the buffer

  // was flushed due to overfilling.

  virtual int InsertPacket(Packet&& packet);

  // Gets the timestamp for the first packet in the buffer and writes it to the

  // output variable `next_timestamp`.

  // Returns PacketBuffer::kBufferEmpty if the buffer is empty,

  // PacketBuffer::kOK otherwise.

  virtual int NextTimestamp(uint32_t* next_timestamp) const;

  // Gets the timestamp for the first packet in the buffer with a timestamp no

  // lower than the input limit `timestamp`. The result is written to the output

  // variable `next_timestamp`.

  // Returns PacketBuffer::kBufferEmpty if the buffer is empty,

  // PacketBuffer::kOK otherwise.

  virtual int NextHigherTimestamp(uint32_t timestamp,

                                  uint32_t* next_timestamp) const;

  // Returns a (constant) pointer to the first packet in the buffer. Returns

  // NULL if the buffer is empty.

  virtual const Packet* PeekNextPacket() const;

  // Extracts the first packet in the buffer and returns it.

  // Returns an empty optional if the buffer is empty.

  virtual absl::optional<Packet> GetNextPacket();

  // Discards the first packet in the buffer. The packet is deleted.

  // Returns PacketBuffer::kBufferEmpty if the buffer is empty,

  // PacketBuffer::kOK otherwise.

  virtual int DiscardNextPacket();

  // Discards all packets that are (strictly) older than timestamp_limit,

  // but newer than timestamp_limit - horizon_samples. Setting horizon_samples

  // to zero implies that the horizon is set to half the timestamp range. That

  // is, if a packet is more than 2^31 timestamps into the future compared with

  // timestamp_limit (including wrap-around), it is considered old.

  virtual void DiscardOldPackets(uint32_t timestamp_limit,

                                 uint32_t horizon_samples);

  // Discards all packets that are (strictly) older than timestamp_limit.

  virtual void DiscardAllOldPackets(uint32_t timestamp_limit);

  // Removes all packets with a specific payload type from the buffer.

  virtual void DiscardPacketsWithPayloadType(uint8_t payload_type);

  // Returns the number of packets in the buffer, including duplicates and

  // redundant packets.

  virtual size_t NumPacketsInBuffer() const;

  // Returns the number of samples in the buffer, including samples carried in

  // duplicate and redundant packets.

  virtual size_t NumSamplesInBuffer(size_t last_decoded_length) const;

  // Returns the total duration in samples that the packets in the buffer spans

  // across.

  virtual size_t GetSpanSamples(size_t last_decoded_length,

                                size_t sample_rate,

                                bool count_waiting_time) const;

  // Returns true if the packet buffer contains any DTX or CNG packets.

  virtual bool ContainsDtxOrCngPacket(

      const DecoderDatabase* decoder_database) const;

  // Static method returning true if `timestamp` is older than `timestamp_limit`

  // but less than `horizon_samples` behind `timestamp_limit`. For instance,

  // with timestamp_limit = 100 and horizon_samples = 10, a timestamp in the

  // range (90, 100) is considered obsolete, and will yield true.

  // Setting `horizon_samples` to 0 is the same as setting it to 2^31, i.e.,

  // half the 32-bit timestamp range.

  static bool IsObsoleteTimestamp(uint32_t timestamp,

                                  uint32_t timestamp_limit,

                                  uint32_t horizon_samples) {

    return IsNewerTimestamp(timestamp_limit, timestamp) &&

           (horizon_samples == 0 ||

            IsNewerTimestamp(timestamp, timestamp_limit - horizon_samples));

 private:

  void LogPacketDiscarded(int codec_level);

  size_t max_number_of_packets_;

  PacketList buffer_;

  const TickTimer* tick_timer_;

  StatisticsCalculator* stats_;

};

}  // namespace webrtc

#endif  // MODULES_AUDIO_CODING_NETEQ_PACKET_BUFFER_H_