video_engine/include/vie_codec.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.
 */

// This sub-API supports the following functionalities:
//  - Setting send and receive codecs.
//  - Codec specific settings.
//  - Key frame signaling.
//  - Stream management settings.

#ifndef WEBRTC_VIDEO_ENGINE_INCLUDE_VIE_CODEC_H_
#define WEBRTC_VIDEO_ENGINE_INCLUDE_VIE_CODEC_H_

#include "common_types.h"

namespace webrtc {

class VideoEngine;
struct VideoCodec;

// This class declares an abstract interface for a user defined observer. It is
// up to the VideoEngine user to implement a derived class which implements the
// observer class. The observer is registered using RegisterEncoderObserver()
// and deregistered using DeregisterEncoderObserver().
class WEBRTC_DLLEXPORT ViEEncoderObserver {
 public:
  // This method is called once per second with the current encoded frame rate
  // and bit rate.
  virtual void OutgoingRate(const int video_channel,
                            const unsigned int framerate,
                            const unsigned int bitrate) = 0;
 protected:
  virtual ~ViEEncoderObserver() {}
};

// This class declares an abstract interface for a user defined observer. It is
// up to the VideoEngine user to implement a derived class which implements the
// observer class. The observer is registered using RegisterDecoderObserver()
// and deregistered using DeregisterDecoderObserver().
class WEBRTC_DLLEXPORT ViEDecoderObserver {
 public:
  // This method is called when a new incoming stream is detected, normally
  // triggered by a new incoming SSRC or payload type.
  virtual void IncomingCodecChanged(const int video_channel,
                                    const VideoCodec& video_codec) = 0;

  // This method is called once per second containing the frame rate and bit
  // rate for the incoming stream
  virtual void IncomingRate(const int video_channel,
                            const unsigned int framerate,
                            const unsigned int bitrate) = 0;

  // This method is called when the decoder needs a new key frame from encoder
  // on the sender.
  virtual void RequestNewKeyFrame(const int video_channel) = 0;

 protected:
  virtual ~ViEDecoderObserver() {}
};

class WEBRTC_DLLEXPORT ViECodec {
 public:
  // Factory for the ViECodec sub‐API and increases an internal reference
  // counter if successful. Returns NULL if the API is not supported or if
  // construction fails.
  static ViECodec* GetInterface(VideoEngine* video_engine);

  // Releases the ViECodec sub-API and decreases an internal reference
  // counter.
  // Returns the new reference count. This value should be zero
  // for all sub-API:s before the VideoEngine object can be safely deleted.
  virtual int Release() = 0;

  // Gets the number of available codecs for the VideoEngine build.
  virtual int NumberOfCodecs() const = 0;

  // Gets a VideoCodec struct for a codec containing the default configuration
  // for that codec type.
  virtual int GetCodec(const unsigned char list_number,
                       VideoCodec& video_codec) const = 0;

  // Sets the send codec to use for a specified channel.
  virtual int SetSendCodec(const int video_channel,
                           const VideoCodec& video_codec) = 0;

  // Gets the current send codec settings.
  virtual int GetSendCodec(const int video_channel,
                           VideoCodec& video_codec) const = 0;

  // Prepares VideoEngine to receive a certain codec type and setting for a
  // specified payload type.
  virtual int SetReceiveCodec(const int video_channel,
                              const VideoCodec& video_codec) = 0;

  // Gets the current receive codec.
  virtual int GetReceiveCodec(const int video_channel,
                              VideoCodec& video_codec) const = 0;

  // This function is used to get codec configuration parameters to be
  // signaled from the encoder to the decoder in the call setup.
  virtual int GetCodecConfigParameters(
      const int video_channel,
      unsigned char config_parameters[kConfigParameterSize],
      unsigned char& config_parameters_size) const = 0;

  // Enables advanced scaling of the captured video stream if the stream
  // differs from the send codec settings.
  virtual int SetImageScaleStatus(const int video_channel,
                                  const bool enable) = 0;

  // Gets the number of sent key frames and number of sent delta frames.
  virtual int GetSendCodecStastistics(const int video_channel,
                                      unsigned int& key_frames,
                                      unsigned int& delta_frames) const = 0;

  // Gets the number of decoded key frames and number of decoded delta frames.
  virtual int GetReceiveCodecStastistics(const int video_channel,
                                         unsigned int& key_frames,
                                         unsigned int& delta_frames) const = 0;

  // Estimate of the min required buffer time from the expected arrival time
  // until rendering to get smooth playback.
  virtual int GetReceiveSideDelay(const int video_channel,
                                  int* delay_ms) const = 0;

  // Gets the bitrate targeted by the video codec rate control in kbit/s.
  virtual int GetCodecTargetBitrate(const int video_channel,
                                    unsigned int* bitrate) const = 0;

  // Gets the number of packets discarded by the jitter buffer because they
  // arrived too late.
  virtual unsigned int GetDiscardedPackets(const int video_channel) const = 0;

  // Enables key frame request callback in ViEDecoderObserver.
  virtual int SetKeyFrameRequestCallbackStatus(const int video_channel,
                                               const bool enable) = 0;

  // Enables key frame requests for detected lost packets.
  virtual int SetSignalKeyPacketLossStatus(
      const int video_channel,
      const bool enable,
      const bool only_key_frames = false) = 0;

  // Registers an instance of a user implementation of the ViEEncoderObserver.
  virtual int RegisterEncoderObserver(const int video_channel,
                                      ViEEncoderObserver& observer) = 0;

  // Removes an already registered instance of ViEEncoderObserver.
  virtual int DeregisterEncoderObserver(const int video_channel) = 0;

  // Registers an instance of a user implementation of the ViEDecoderObserver.
  virtual int RegisterDecoderObserver(const int video_channel,
                                      ViEDecoderObserver& observer) = 0;

  // Removes an already registered instance of ViEDecoderObserver.
  virtual int DeregisterDecoderObserver(const int video_channel) = 0;

  // This function forces the next encoded frame to be a key frame. This is
  // normally used when the remote endpoint only supports out‐band key frame
  // request.
  virtual int SendKeyFrame(const int video_channel) = 0;

  // This function makes the decoder wait for a key frame before starting to
  // decode the incoming video stream.
  virtual int WaitForFirstKeyFrame(const int video_channel,
                                   const bool wait) = 0;

 protected:
  ViECodec() {}
  virtual ~ViECodec() {}
};

}  // namespace webrtc

#endif  // WEBRTC_VIDEO_ENGINE_INCLUDE_VIE_CODEC_H_