timestamp_scaler.h

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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_TIMESTAMP_SCALER_H_

#define MODULES_AUDIO_CODING_NETEQ_TIMESTAMP_SCALER_H_

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

namespace webrtc {

// Forward declaration.

class DecoderDatabase;

// This class scales timestamps for codecs that need timestamp scaling.

// This is done for codecs where one RTP timestamp does not correspond to

// one sample.

class TimestampScaler {

 public:

  explicit TimestampScaler(const DecoderDatabase& decoder_database)

      : first_packet_received_(false),

        numerator_(1),

        denominator_(1),

        external_ref_(0),

        internal_ref_(0),

        decoder_database_(decoder_database) {}

  virtual ~TimestampScaler() {}

  TimestampScaler(const TimestampScaler&) = delete;

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

  // Start over.

  virtual void Reset();

  // Scale the timestamp in `packet` from external to internal.

  virtual void ToInternal(Packet* packet);

  // Scale the timestamp for all packets in `packet_list` from external to

  // internal.

  virtual void ToInternal(PacketList* packet_list);

  // Returns the internal equivalent of `external_timestamp`, given the

  // RTP payload type `rtp_payload_type`.

  virtual uint32_t ToInternal(uint32_t external_timestamp,

                              uint8_t rtp_payload_type);

  // Scales back to external timestamp. This is the inverse of ToInternal().

  virtual uint32_t ToExternal(uint32_t internal_timestamp) const;

 private:

  bool first_packet_received_;

  int numerator_;

  int denominator_;

  uint32_t external_ref_;

  uint32_t internal_ref_;

  const DecoderDatabase& decoder_database_;

};

}  // namespace webrtc

#endif  // MODULES_AUDIO_CODING_NETEQ_TIMESTAMP_SCALER_H_