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_PAYLOAD_SPLITTER_H_
12#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_PAYLOAD_SPLITTER_H_
13
14#include "webrtc/base/constructormagic.h"
15#include "webrtc/modules/audio_coding/neteq/packet.h"
16
17namespace webrtc {
18
19// Forward declarations.
20class DecoderDatabase;
21
22// This class handles splitting of payloads into smaller parts.
23// The class does not have any member variables, and the methods could have
24// been made static. The reason for not making them static is testability.
25// With this design, the splitting functionality can be mocked during testing
26// of the NetEqImpl class.
27class PayloadSplitter {
28 public:
29  enum SplitterReturnCodes {
30    kOK = 0,
31    kNoSplit = 1,
32    kTooLargePayload = -1,
33    kFrameSplitError = -2,
34    kUnknownPayloadType = -3,
35    kRedLengthMismatch = -4,
36    kFecSplitError = -5,
37  };
38
39  PayloadSplitter() {}
40
41  virtual ~PayloadSplitter() {}
42
43  // Splits each packet in |packet_list| into its separate RED payloads. Each
44  // RED payload is packetized into a Packet. The original elements in
45  // |packet_list| are properly deleted, and replaced by the new packets.
46  // Note that all packets in |packet_list| must be RED payloads, i.e., have
47  // RED headers according to RFC 2198 at the very beginning of the payload.
48  // Returns kOK or an error.
49  virtual int SplitRed(PacketList* packet_list);
50
51  // Iterates through |packet_list| and, duplicate each audio payload that has
52  // FEC as new packet for redundant decoding. The decoder database is needed to
53  // get information about which payload type each packet contains.
54  virtual int SplitFec(PacketList* packet_list,
55                       DecoderDatabase* decoder_database);
56
57  // Checks all packets in |packet_list|. Packets that are DTMF events or
58  // comfort noise payloads are kept. Except that, only one single payload type
59  // is accepted. Any packet with another payload type is discarded.
60  virtual int CheckRedPayloads(PacketList* packet_list,
61                               const DecoderDatabase& decoder_database);
62
63  // Iterates through |packet_list| and, if possible, splits each audio payload
64  // into suitable size chunks. The result is written back to |packet_list| as
65  // new packets. The decoder database is needed to get information about which
66  // payload type each packet contains.
67  virtual int SplitAudio(PacketList* packet_list,
68                         const DecoderDatabase& decoder_database);
69
70 private:
71  // Splits the payload in |packet|. The payload is assumed to be from a
72  // sample-based codec.
73  virtual void SplitBySamples(const Packet* packet,
74                              int bytes_per_ms,
75                              int timestamps_per_ms,
76                              PacketList* new_packets);
77
78  // Splits the payload in |packet|. The payload will be split into chunks of
79  // size |bytes_per_frame|, corresponding to a |timestamps_per_frame|
80  // RTP timestamps.
81  virtual int SplitByFrames(const Packet* packet,
82                            int bytes_per_frame,
83                            int timestamps_per_frame,
84                            PacketList* new_packets);
85
86  DISALLOW_COPY_AND_ASSIGN(PayloadSplitter);
87};
88
89}  // namespace webrtc
90#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_PAYLOAD_SPLITTER_H_
91