Home | History | Annotate | Download | only in neteq 
      1 /*
      2  *  Copyright (c) 2012 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 WEBRTC_MODULES_AUDIO_CODING_NETEQ_TIMESTAMP_SCALER_H_
     12 #define WEBRTC_MODULES_AUDIO_CODING_NETEQ_TIMESTAMP_SCALER_H_
     13 
     14 #include "webrtc/base/constructormagic.h"
     15 #include "webrtc/modules/audio_coding/neteq/packet.h"
     16 #include "webrtc/typedefs.h"
     17 
     18 namespace webrtc {
     19 
     20 // Forward declaration.
     21 class DecoderDatabase;
     22 
     23 // This class scales timestamps for codecs that need timestamp scaling.
     24 // This is done for codecs where one RTP timestamp does not correspond to
     25 // one sample.
     26 class TimestampScaler {
     27  public:
     28   explicit TimestampScaler(const DecoderDatabase& decoder_database)
     29       : first_packet_received_(false),
     30         numerator_(1),
     31         denominator_(1),
     32         external_ref_(0),
     33         internal_ref_(0),
     34         decoder_database_(decoder_database) {}
     35 
     36   virtual ~TimestampScaler() {}
     37 
     38   // Start over.
     39   virtual void Reset() { first_packet_received_ = false; }
     40 
     41   // Scale the timestamp in |packet| from external to internal.
     42   virtual void ToInternal(Packet* packet);
     43 
     44   // Scale the timestamp for all packets in |packet_list| from external to
     45   // internal.
     46   virtual void ToInternal(PacketList* packet_list);
     47 
     48   // Returns the internal equivalent of |external_timestamp|, given the
     49   // RTP payload type |rtp_payload_type|.
     50   virtual uint32_t ToInternal(uint32_t external_timestamp,
     51                               uint8_t rtp_payload_type);
     52 
     53   // Scales back to external timestamp. This is the inverse of ToInternal().
     54   virtual uint32_t ToExternal(uint32_t internal_timestamp) const;
     55 
     56  private:
     57   bool first_packet_received_;
     58   int numerator_;
     59   int denominator_;
     60   uint32_t external_ref_;
     61   uint32_t internal_ref_;
     62   const DecoderDatabase& decoder_database_;
     63 
     64   DISALLOW_COPY_AND_ASSIGN(TimestampScaler);
     65 };
     66 
     67 }  // namespace webrtc
     68 #endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_TIMESTAMP_SCALER_H_
     69