webrtc/modules/audio_coding/neteq/decoder_database.h

/*
 *  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 WEBRTC_MODULES_AUDIO_CODING_NETEQ_DECODER_DATABASE_H_
#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_DECODER_DATABASE_H_

#include <map>
#include <memory>
#include <string>

#include "webrtc/base/constructormagic.h"
#include "webrtc/common_types.h"  // NULL
#include "webrtc/modules/audio_coding/codecs/audio_decoder_factory.h"
#include "webrtc/modules/audio_coding/codecs/audio_format.h"
#include "webrtc/modules/audio_coding/codecs/cng/webrtc_cng.h"
#include "webrtc/modules/audio_coding/neteq/audio_decoder_impl.h"
#include "webrtc/modules/audio_coding/neteq/packet.h"
#include "webrtc/typedefs.h"

namespace webrtc {

class DecoderDatabase {
 public:
  enum DatabaseReturnCodes {
    kOK = 0,
    kInvalidRtpPayloadType = -1,
    kCodecNotSupported = -2,
    kInvalidSampleRate = -3,
    kDecoderExists = -4,
    kDecoderNotFound = -5,
    kInvalidPointer = -6
  };

  // Class that stores decoder info in the database.
  class DecoderInfo {
   public:
    DecoderInfo(
        NetEqDecoder ct,
        const std::string& nm,
        AudioDecoderFactory* factory = nullptr);
    DecoderInfo(NetEqDecoder ct,
                const std::string& nm,
                AudioDecoder* ext_dec);
    DecoderInfo(DecoderInfo&&);
    ~DecoderInfo();

    // Get the AudioDecoder object, creating it first if necessary.
    AudioDecoder* GetDecoder() const;

    // Delete the AudioDecoder object, unless it's external. (This means we can
    // always recreate it later if we need it.)
    void DropDecoder() const { decoder_.reset(); }

    int SampleRateHz() const {
      const AudioDecoder* decoder = GetDecoder();
      RTC_DCHECK_EQ(1, !!decoder + !!cng_decoder_);
      return decoder ? decoder->SampleRateHz() : cng_decoder_->sample_rate_hz;
    }

    const SdpAudioFormat& GetFormat() const {
      RTC_DCHECK(audio_format_);
      return *audio_format_;
    }

    // Returns true if |codec_type| is comfort noise.
    bool IsComfortNoise() const;

    // Returns true if |codec_type| is DTMF.
    bool IsDtmf() const;

    // Returns true if |codec_type| is RED.
    bool IsRed() const;

    const NetEqDecoder codec_type;
    const std::string name;

   private:
    const rtc::Optional<SdpAudioFormat> audio_format_;
    AudioDecoderFactory* factory_;
    mutable std::unique_ptr<AudioDecoder> decoder_;

    // Set iff this is an external decoder.
    AudioDecoder* const external_decoder_;

    // Set iff this is a comfort noise decoder.
    struct CngDecoder {
      static rtc::Optional<CngDecoder> Create(NetEqDecoder ct);
      int sample_rate_hz;
    };
    const rtc::Optional<CngDecoder> cng_decoder_;
  };

  // Maximum value for 8 bits, and an invalid RTP payload type (since it is
  // only 7 bits).
  static const uint8_t kRtpPayloadTypeError = 0xFF;

  DecoderDatabase(
      const rtc::scoped_refptr<AudioDecoderFactory>& decoder_factory);

  virtual ~DecoderDatabase();

  // Returns true if the database is empty.
  virtual bool Empty() const;

  // Returns the number of decoders registered in the database.
  virtual int Size() const;

  // Resets the database, erasing all registered payload types, and deleting
  // any AudioDecoder objects that were not externally created and inserted
  // using InsertExternal().
  virtual void Reset();

  // Registers |rtp_payload_type| as a decoder of type |codec_type|. The |name|
  // is only used to populate the name field in the DecoderInfo struct in the
  // database, and can be arbitrary (including empty). Returns kOK on success;
  // otherwise an error code.
  virtual int RegisterPayload(uint8_t rtp_payload_type,
                              NetEqDecoder codec_type,
                              const std::string& name);

  // Registers an externally created AudioDecoder object, and associates it
  // as a decoder of type |codec_type| with |rtp_payload_type|.
  virtual int InsertExternal(uint8_t rtp_payload_type,
                             NetEqDecoder codec_type,
                             const std::string& codec_name,
                             AudioDecoder* decoder);

  // Removes the entry for |rtp_payload_type| from the database.
  // Returns kDecoderNotFound or kOK depending on the outcome of the operation.
  virtual int Remove(uint8_t rtp_payload_type);

  // Returns a pointer to the DecoderInfo struct for |rtp_payload_type|. If
  // no decoder is registered with that |rtp_payload_type|, NULL is returned.
  virtual const DecoderInfo* GetDecoderInfo(uint8_t rtp_payload_type) const;

  // Returns one RTP payload type associated with |codec_type|, or
  // kDecoderNotFound if no entry exists for that value. Note that one
  // |codec_type| may be registered with several RTP payload types, and the
  // method may return any of them.
  virtual uint8_t GetRtpPayloadType(NetEqDecoder codec_type) const;

  // Sets the active decoder to be |rtp_payload_type|. If this call results in a
  // change of active decoder, |new_decoder| is set to true. The previous active
  // decoder's AudioDecoder object is deleted.
  virtual int SetActiveDecoder(uint8_t rtp_payload_type, bool* new_decoder);

  // Returns the current active decoder, or NULL if no active decoder exists.
  virtual AudioDecoder* GetActiveDecoder() const;

  // Sets the active comfort noise decoder to be |rtp_payload_type|. If this
  // call results in a change of active comfort noise decoder, the previous
  // active decoder's AudioDecoder object is deleted.
  virtual int SetActiveCngDecoder(uint8_t rtp_payload_type);

  // Returns the current active comfort noise decoder, or NULL if no active
  // comfort noise decoder exists.
  virtual ComfortNoiseDecoder* GetActiveCngDecoder() const;

  // The following are utility methods: they will look up DecoderInfo through
  // GetDecoderInfo and call the respective method on that info object, if it
  // exists.

  // Returns a pointer to the AudioDecoder object associated with
  // |rtp_payload_type|, or NULL if none is registered. If the AudioDecoder
  // object does not exist for that decoder, the object is created.
  AudioDecoder* GetDecoder(uint8_t rtp_payload_type) const;

  // Returns true if |rtp_payload_type| is registered as a |codec_type|.
  bool IsType(uint8_t rtp_payload_type, NetEqDecoder codec_type) const;

  // Returns true if |rtp_payload_type| is registered as comfort noise.
  bool IsComfortNoise(uint8_t rtp_payload_type) const;

  // Returns true if |rtp_payload_type| is registered as DTMF.
  bool IsDtmf(uint8_t rtp_payload_type) const;

  // Returns true if |rtp_payload_type| is registered as RED.
  bool IsRed(uint8_t rtp_payload_type) const;

  // Returns kOK if all packets in |packet_list| carry payload types that are
  // registered in the database. Otherwise, returns kDecoderNotFound.
  int CheckPayloadTypes(const PacketList& packet_list) const;

 private:
  typedef std::map<uint8_t, DecoderInfo> DecoderMap;

  DecoderMap decoders_;
  int active_decoder_type_;
  int active_cng_decoder_type_;
  mutable std::unique_ptr<ComfortNoiseDecoder> active_cng_decoder_;
  rtc::scoped_refptr<AudioDecoderFactory> decoder_factory_;

  RTC_DISALLOW_COPY_AND_ASSIGN(DecoderDatabase);
};

}  // namespace webrtc
#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_DECODER_DATABASE_H_