toxcore/toxav/toxav.api.h

%{
/* SPDX-License-Identifier: GPL-3.0-or-later
 * Copyright © 2016-2018 The TokTok team.
 * Copyright © 2013-2015 Tox project.
 */
#ifndef C_TOXCORE_TOXAV_TOXAV_H
#define C_TOXCORE_TOXAV_TOXAV_H

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

//!TOKSTYLE-

#ifdef __cplusplus
extern "C" {
#endif
%}

/** \page av Public audio/video API for Tox clients.
 *
 * This API can handle multiple calls. Each call has its state, in very rare
 * occasions the library can change the state of the call without apps knowledge.
 *
 */

/** \subsection events Events and callbacks
 *
 * As in Core API, events are handled by callbacks. One callback can be
 * registered per event. All events have a callback function type named
 * `toxav_{event}_cb` and a function to register it named `toxav_callback_{event}`.
 * Passing a NULL callback will result in no callback being registered for that
 * event. Only one callback per event can be registered, so if a client needs
 * multiple event listeners, it needs to implement the dispatch functionality
 * itself. Unlike Core API, lack of some event handlers will cause the the
 * library to drop calls before they are started. Hanging up call from a
 * callback causes undefined behaviour.
 *
 */

/** \subsection threading Threading implications
 *
 * Only ${toxAV.iterate} is thread-safe, all other functions must run from the
 * tox thread.
 *
 * Important exceptions are the `*_iterate` and `*_iterate_interval`
 * functions. You have to choose either the single thread or the multi thread
 * functions and read their documentation.
 *
 * A common way to run ToxAV (multiple or single instance) is to have a thread,
 * separate from tox instance thread, running a simple ${toxAV.iterate} loop,
 * sleeping for ${toxAV.iteration_interval} * milliseconds on each iteration.
 *
 * An important thing to note is that events are triggered from both tox and
 * toxav thread (see above). Audio and video receive frame events are triggered
 * from toxav thread while all the other events are triggered from tox thread.
 *
 * Tox thread has priority with mutex mechanisms. Any api function can
 * fail if mutexes are held by tox thread in which case they will set SYNC
 * error code.
 */

/** \subsection multi-threading Separate audio and video threads
 *
 * ToxAV supports either a single thread for audio and video or decoding and
 * encoding them in separate threads. You have to choose one mode and can not
 * mix function calls to those different modes.
 *
 * For best results use the multi-threaded mode and run the audio thread with
 * higher priority than the video thread. This prioritizes audio over video.
 */

/**
 * External Tox type.
 */
class tox {
  struct this;
}

/**
 * ToxAV.
 */
class toxAV {

/**
 * The ToxAV instance type. Each ToxAV instance can be bound to only one Tox
 * instance, and Tox instance can have only one ToxAV instance. One must make
 * sure to close ToxAV instance prior closing Tox instance otherwise undefined
 * behaviour occurs. Upon closing of ToxAV instance, all active calls will be
 * forcibly terminated without notifying peers.
 *
 */
struct this;

/*******************************************************************************
 *
 * :: Creation and destruction
 *
 ******************************************************************************/


/**
 * Start new A/V session. There can only be only one session per Tox instance.
 */
static this new(tox::this *tox) {
  NULL,
  /**
   * Memory allocation failure while trying to allocate structures required for
   * the A/V session.
   */
  MALLOC,
  /**
   * Attempted to create a second session for the same Tox instance.
   */
  MULTIPLE,
}

/**
 * Releases all resources associated with the A/V session.
 *
 * If any calls were ongoing, these will be forcibly terminated without
 * notifying peers. After calling this function, no other functions may be
 * called and the av pointer becomes invalid.
 */
void kill();

/**
 * Returns the Tox instance the A/V object was created for.
 */
tox::this *tox { get(); }


/*******************************************************************************
 *
 * :: A/V event loop, single thread
 *
 ******************************************************************************/


/**
 * Returns the interval in milliseconds when the next toxav_iterate call should
 * be. If no call is active at the moment, this function returns 200.
 * This function MUST be called from the same thread as toxav_iterate.
 */
const uint32_t iteration_interval();

/**
 * Main loop for the session. This function needs to be called in intervals of
 * toxav_iteration_interval() milliseconds. It is best called in the separate
 * thread from tox_iterate.
 */
void iterate();

/*******************************************************************************
 *
 * :: A/V event loop, multiple threads
 *
 ******************************************************************************/

/**
 * Returns the interval in milliseconds when the next toxav_audio_iterate call
 * should be. If no call is active at the moment, this function returns 200.
 * This function MUST be called from the same thread as toxav_audio_iterate.
 */
const uint32_t audio_iteration_interval();

/**
 * Main loop for the session. This function needs to be called in intervals of
 * toxav_audio_iteration_interval() milliseconds. It is best called in a
 * separate thread from tox_iterate and toxav_video_iterate. The thread calling
 * this function should have higher priority than the one calling
 * toxav_video_iterate to prioritize audio over video.
 */
void audio_iterate();

/**
 * Returns the interval in milliseconds when the next toxav_video_iterate call
 * should be. If no call is active at the moment, this function returns 200.
 * This function MUST be called from the same thread as toxav_video_iterate.
 */
const uint32_t video_iteration_interval();

/**
 * Main loop for the session. This function needs to be called in intervals of
 * toxav_video_iteration_interval() milliseconds. It is best called in a
 * separate thread from tox_iterate and toxav_audio_iterate. The thread calling
 * this function should have lower priority than the one calling
 * toxav_audio_iterate to prioritize audio over video.
 */
void video_iterate();

/*******************************************************************************
 *
 * :: Call setup
 *
 ******************************************************************************/


/**
 * Call a friend. This will start ringing the friend.
 *
 * It is the client's responsibility to stop ringing after a certain timeout,
 * if such behaviour is desired. If the client does not stop ringing, the
 * library will not stop until the friend is disconnected. Audio and video
 * receiving are both enabled by default.
 *
 * @param friend_number The friend number of the friend that should be called.
 * @param audio_bit_rate Audio bit rate in Kb/sec. Set this to 0 to disable
 * audio sending.
 * @param video_bit_rate Video bit rate in Kb/sec. Set this to 0 to disable
 * video sending.
 */
bool call(uint32_t friend_number, uint32_t audio_bit_rate, uint32_t video_bit_rate) {
  /**
   * A resource allocation error occurred while trying to create the structures
   * required for the call.
   */
  MALLOC,
  /**
   * Synchronization error occurred.
   */
  SYNC,
  /**
   * The friend number did not designate a valid friend.
   */
  FRIEND_NOT_FOUND,
  /**
   * The friend was valid, but not currently connected.
   */
  FRIEND_NOT_CONNECTED,
  /**
   * Attempted to call a friend while already in an audio or video call with
   * them.
   */
  FRIEND_ALREADY_IN_CALL,
  /**
   * Audio or video bit rate is invalid.
   */
  INVALID_BIT_RATE,
}

event call {
  /**
   * The function type for the ${event call} callback.
   *
   * @param friend_number The friend number from which the call is incoming.
   * @param audio_enabled True if friend is sending audio.
   * @param video_enabled True if friend is sending video.
   */
  typedef void(uint32_t friend_number, bool audio_enabled, bool video_enabled);
}

/**
 * Accept an incoming call.
 *
 * If answering fails for any reason, the call will still be pending and it is
 * possible to try and answer it later. Audio and video receiving are both
 * enabled by default.
 *
 * @param friend_number The friend number of the friend that is calling.
 * @param audio_bit_rate Audio bit rate in Kb/sec. Set this to 0 to disable
 * audio sending.
 * @param video_bit_rate Video bit rate in Kb/sec. Set this to 0 to disable
 * video sending.
 */
bool answer(uint32_t friend_number, uint32_t audio_bit_rate, uint32_t video_bit_rate) {
  /**
   * Synchronization error occurred.
   */
  SYNC,
  /**
   * Failed to initialize codecs for call session. Note that codec initiation
   * will fail if there is no receive callback registered for either audio or
   * video.
   */
  CODEC_INITIALIZATION,
  /**
   * The friend number did not designate a valid friend.
   */
  FRIEND_NOT_FOUND,
  /**
   * The friend was valid, but they are not currently trying to initiate a call.
   * This is also returned if this client is already in a call with the friend.
   */
  FRIEND_NOT_CALLING,
  /**
   * Audio or video bit rate is invalid.
   */
  INVALID_BIT_RATE,
}


/*******************************************************************************
 *
 * :: Call state graph
 *
 ******************************************************************************/


bitmask FRIEND_CALL_STATE {
  /**
   * Set by the AV core if an error occurred on the remote end or if friend
   * timed out. This is the final state after which no more state
   * transitions can occur for the call. This call state will never be triggered
   * in combination with other call states.
   */
  ERROR,
  /**
   * The call has finished. This is the final state after which no more state
   * transitions can occur for the call. This call state will never be
   * triggered in combination with other call states.
   */
  FINISHED,
  /**
   * The flag that marks that friend is sending audio.
   */
  SENDING_A,
  /**
   * The flag that marks that friend is sending video.
   */
  SENDING_V,
  /**
   * The flag that marks that friend is receiving audio.
   */
  ACCEPTING_A,
  /**
   * The flag that marks that friend is receiving video.
   */
  ACCEPTING_V,
}

event call_state {
 /**
  * The function type for the ${event call_state} callback.
  *
  * @param friend_number The friend number for which the call state changed.
  * @param state The bitmask of the new call state which is guaranteed to be
  * different than the previous state. The state is set to 0 when the call is
  * paused. The bitmask represents all the activities currently performed by the
  * friend.
  */
  typedef void(uint32_t friend_number, uint32_t state);
}


/*******************************************************************************
 *
 * :: Call control
 *
 ******************************************************************************/


enum class CALL_CONTROL {
    /**
     * Resume a previously paused call. Only valid if the pause was caused by this
     * client, if not, this control is ignored. Not valid before the call is accepted.
     */
    RESUME,
    /**
     * Put a call on hold. Not valid before the call is accepted.
     */
    PAUSE,
    /**
     * Reject a call if it was not answered, yet. Cancel a call after it was
     * answered.
     */
    CANCEL,
    /**
     * Request that the friend stops sending audio. Regardless of the friend's
     * compliance, this will cause the ${event audio.receive_frame} event to stop being
     * triggered on receiving an audio frame from the friend.
     */
    MUTE_AUDIO,
    /**
     * Calling this control will notify client to start sending audio again.
     */
    UNMUTE_AUDIO,
    /**
     * Request that the friend stops sending video. Regardless of the friend's
     * compliance, this will cause the ${event video.receive_frame} event to stop being
     * triggered on receiving a video frame from the friend.
     */
    HIDE_VIDEO,
    /**
     * Calling this control will notify client to start sending video again.
     */
    SHOW_VIDEO,
}

/**
 * Sends a call control command to a friend.
 *
 * @param friend_number The friend number of the friend this client is in a call
 * with.
 * @param control The control command to send.
 *
 * @return true on success.
 */
bool call_control(uint32_t friend_number, CALL_CONTROL control) {
  /**
   * Synchronization error occurred.
   */
  SYNC,
  /**
   * The friend_number passed did not designate a valid friend.
   */
  FRIEND_NOT_FOUND,
  /**
   * This client is currently not in a call with the friend. Before the call is
   * answered, only CANCEL is a valid control.
   */
  FRIEND_NOT_IN_CALL,
  /**
   * Happens if user tried to pause an already paused call or if trying to
   * resume a call that is not paused.
   */
  INVALID_TRANSITION,
}


/*******************************************************************************
 *
 * :: Controlling bit rates
 *
 ******************************************************************************/


error for bit_rate_set {
  /**
   * Synchronization error occurred.
   */
  SYNC,
  /**
   * The bit rate passed was not one of the supported values.
   */
  INVALID_BIT_RATE,
  /**
   * The friend_number passed did not designate a valid friend.
   */
  FRIEND_NOT_FOUND,
  /**
   * This client is currently not in a call with the friend.
   */
  FRIEND_NOT_IN_CALL,
}

/*******************************************************************************
 *
 * :: A/V sending
 *
 ******************************************************************************/


error for send_frame {
  /**
   * In case of video, one of Y, U, or V was NULL. In case of audio, the samples
   * data pointer was NULL.
   */
  NULL,
  /**
   * The friend_number passed did not designate a valid friend.
   */
  FRIEND_NOT_FOUND,
  /**
   * This client is currently not in a call with the friend.
   */
  FRIEND_NOT_IN_CALL,
  /**
   * Synchronization error occurred.
   */
  SYNC,
  /**
   * One of the frame parameters was invalid. E.g. the resolution may be too
   * small or too large, or the audio sampling rate may be unsupported.
   */
  INVALID,
  /**
   * Either friend turned off audio or video receiving or we turned off sending
   * for the said payload.
   */
  PAYLOAD_TYPE_DISABLED,
  /**
   * Failed to push frame through rtp interface.
   */
  RTP_FAILED,
}

namespace audio {
  /**
   * Send an audio frame to a friend.
   *
   * The expected format of the PCM data is: [s1c1][s1c2][...][s2c1][s2c2][...]...
   * Meaning: sample 1 for channel 1, sample 1 for channel 2, ...
   * For mono audio, this has no meaning, every sample is subsequent. For stereo,
   * this means the expected format is LRLRLR... with samples for left and right
   * alternating.
   *
   * @param friend_number The friend number of the friend to which to send an
   * audio frame.
   * @param pcm An array of audio samples. The size of this array must be
   * sample_count * channels.
   * @param sample_count Number of samples in this frame. Valid numbers here are
   * ((sample rate) * (audio length) / 1000), where audio length can be
   * 2.5, 5, 10, 20, 40 or 60 millseconds.
   * @param channels Number of audio channels. Supported values are 1 and 2.
   * @param sampling_rate Audio sampling rate used in this frame. Valid sampling
   * rates are 8000, 12000, 16000, 24000, or 48000.
   */
  bool send_frame(uint32_t friend_number, const int16_t *pcm, size_t sample_count,
                  uint8_t channels, uint32_t sampling_rate) with error for send_frame;

  uint32_t bit_rate {
    /**
     * Set the bit rate to be used in subsequent video frames.
     *
     * @param friend_number The friend number of the friend for which to set the
     * bit rate.
     * @param bit_rate The new audio bit rate in Kb/sec. Set to 0 to disable.
     *
     * @return true on success.
     */
    set(uint32_t friend_number) with error for bit_rate_set;
  }

  event bit_rate {
    /**
     * The function type for the ${event bit_rate} callback. The event is triggered
     * when the network becomes too saturated for current bit rates at which
     * point core suggests new bit rates.
     *
     * @param friend_number The friend number of the friend for which to set the
     * bit rate.
     * @param audio_bit_rate Suggested maximum audio bit rate in Kb/sec.
     */
    typedef void(uint32_t friend_number, uint32_t audio_bit_rate);
  }
}

namespace video {
  /**
   * Send a video frame to a friend.
   *
   * Y - plane should be of size: height * width
   * U - plane should be of size: (height/2) * (width/2)
   * V - plane should be of size: (height/2) * (width/2)
   *
   * @param friend_number The friend number of the friend to which to send a video
   * frame.
   * @param width Width of the frame in pixels.
   * @param height Height of the frame in pixels.
   * @param y Y (Luminance) plane data.
   * @param u U (Chroma) plane data.
   * @param v V (Chroma) plane data.
   */
  bool send_frame(uint32_t friend_number, uint16_t width, uint16_t height,
                  const uint8_t *y, const uint8_t *u, const uint8_t *v) with error for send_frame;

  uint32_t bit_rate {
    /**
     * Set the bit rate to be used in subsequent video frames.
     *
     * @param friend_number The friend number of the friend for which to set the
     * bit rate.
     * @param bit_rate The new video bit rate in Kb/sec. Set to 0 to disable.
     *
     * @return true on success.
     */
    set(uint32_t friend_number) with error for bit_rate_set;
  }

  event bit_rate {
    /**
     * The function type for the ${event bit_rate} callback. The event is triggered
     * when the network becomes too saturated for current bit rates at which
     * point core suggests new bit rates.
     *
     * @param friend_number The friend number of the friend for which to set the
     * bit rate.
     * @param video_bit_rate Suggested maximum video bit rate in Kb/sec.
     */
    typedef void(uint32_t friend_number, uint32_t video_bit_rate);
  }
}


/*******************************************************************************
 *
 * :: A/V receiving
 *
 ******************************************************************************/


namespace audio {
  event receive_frame {
    /**
     * The function type for the ${event receive_frame} callback. The callback can be
     * called multiple times per single iteration depending on the amount of queued
     * frames in the buffer. The received format is the same as in send function.
     *
     * @param friend_number The friend number of the friend who sent an audio frame.
     * @param pcm An array of audio samples (sample_count * channels elements).
     * @param sample_count The number of audio samples per channel in the PCM array.
     * @param channels Number of audio channels.
     * @param sampling_rate Sampling rate used in this frame.
     *
     */
    typedef void(uint32_t friend_number, const int16_t *pcm, size_t sample_count,
                 uint8_t channels, uint32_t sampling_rate);
  }
}

namespace video {
  event receive_frame {
    /**
     * The function type for the ${event receive_frame} callback.
     *
     * The size of plane data is derived from width and height as documented
     * below.
     *
     * Strides represent padding for each plane that may or may not be present.
     * You must handle strides in your image processing code. Strides are
     * negative if the image is bottom-up hence why you MUST abs() it when
     * calculating plane buffer size.
     *
     * @param friend_number The friend number of the friend who sent a video frame.
     * @param width Width of the frame in pixels.
     * @param height Height of the frame in pixels.
     * @param y Luminosity plane. Size = MAX(width, abs(ystride)) * height.
     * @param u U chroma plane. Size = MAX(width/2, abs(ustride)) * (height/2).
     * @param v V chroma plane. Size = MAX(width/2, abs(vstride)) * (height/2).
     *
     * @param ystride Luminosity plane stride.
     * @param ustride U chroma plane stride.
     * @param vstride V chroma plane stride.
     */
    typedef void(uint32_t friend_number, uint16_t width, uint16_t height,
                 const uint8_t *y, const uint8_t *u, const uint8_t *v,
                 int32_t ystride, int32_t ustride, int32_t vstride);
  }
}

}

%{
/**
 * NOTE Compatibility with old toxav group calls. TODO(iphydf): remove
 *
 * TODO(iphydf): Use proper new API guidelines for these. E.g. don't use inline
 * function types, don't have per-callback userdata, especially don't have one
 * userdata per group.
 */
/* Create a new toxav group.
 *
 * return group number on success.
 * return -1 on failure.
 *
 * Audio data callback format:
 *   audio_callback(Tox *tox, uint32_t groupnumber, uint32_t peernumber, const int16_t *pcm, unsigned int samples, uint8_t channels, uint32_t sample_rate, void *userdata)
 *
 * Note that total size of pcm in bytes is equal to (samples * channels * sizeof(int16_t)).
 */
int toxav_add_av_groupchat(Tox *tox,
                           void (*audio_callback)(void *, uint32_t, uint32_t, const int16_t *, unsigned int, uint8_t, uint32_t, void *),
                           void *userdata);

/* Join a AV group (you need to have been invited first.)
 *
 * returns group number on success
 * returns -1 on failure.
 *
 * Audio data callback format (same as the one for toxav_add_av_groupchat()):
 *   audio_callback(Tox *tox, uint32_t groupnumber, uint32_t peernumber, const int16_t *pcm, unsigned int samples, uint8_t channels, uint32_t sample_rate, void *userdata)
 *
 * Note that total size of pcm in bytes is equal to (samples * channels * sizeof(int16_t)).
 */
int toxav_join_av_groupchat(Tox *tox, uint32_t friendnumber, const uint8_t *data, uint16_t length,
                            void (*audio_callback)(void *, uint32_t, uint32_t, const int16_t *, unsigned int, uint8_t, uint32_t, void *),
                            void *userdata);

/* Send audio to the group chat.
 *
 * return 0 on success.
 * return -1 on failure.
 *
 * Note that total size of pcm in bytes is equal to (samples * channels * sizeof(int16_t)).
 *
 * Valid number of samples are ((sample rate) * (audio length (Valid ones are: 2.5, 5, 10, 20, 40 or 60 ms)) / 1000)
 * Valid number of channels are 1 or 2.
 * Valid sample rates are 8000, 12000, 16000, 24000, or 48000.
 *
 * Recommended values are: samples = 960, channels = 1, sample_rate = 48000
 */
int toxav_group_send_audio(Tox *tox, uint32_t groupnumber, const int16_t *pcm, unsigned int samples, uint8_t channels,
                           uint32_t sample_rate);

/* Enable A/V in a groupchat.
 *
 * A/V must be enabled on a groupchat for audio to be sent to it and for
 * received audio to be handled.
 *
 * An A/V group created with toxav_add_av_groupchat or toxav_join_av_groupchat
 * will start with A/V enabled.
 *
 * An A/V group loaded from a savefile will start with A/V disabled.
 *
 * return 0 on success.
 * return -1 on failure.
 *
 * Audio data callback format (same as the one for toxav_add_av_groupchat()):
 *   audio_callback(Tox *tox, uint32_t groupnumber, uint32_t peernumber, const int16_t *pcm, unsigned int samples, uint8_t channels, uint32_t sample_rate, void *userdata)
 *
 * Note that total size of pcm in bytes is equal to (samples * channels * sizeof(int16_t)).
 */
int toxav_groupchat_enable_av(Tox *tox, uint32_t groupnumber,
                              void (*audio_callback)(void *, uint32_t, uint32_t, const int16_t *, unsigned int, uint8_t, uint32_t, void *),
                              void *userdata);

/* Disable A/V in a groupchat.
 *
 * return 0 on success.
 * return -1 on failure.
 */
int toxav_groupchat_disable_av(Tox *tox, uint32_t groupnumber);

/* Return whether A/V is enabled in the groupchat.
 */
bool toxav_groupchat_av_enabled(Tox *tox, uint32_t groupnumber);

#ifdef __cplusplus
}
#endif

typedef void toxav_group_audio_cb(Tox *tox, uint32_t groupnumber, uint32_t peernumber, const int16_t *pcm, uint32_t samples, uint8_t channels, uint32_t sample_rate, void *user_data);

typedef TOXAV_ERR_CALL Toxav_Err_Call;
typedef TOXAV_ERR_NEW Toxav_Err_New;
typedef TOXAV_ERR_ANSWER Toxav_Err_Answer;
typedef TOXAV_ERR_CALL_CONTROL Toxav_Err_Call_Control;
typedef TOXAV_ERR_BIT_RATE_SET Toxav_Err_Bit_Rate_Set;
typedef TOXAV_ERR_SEND_FRAME Toxav_Err_Send_Frame;
typedef TOXAV_CALL_CONTROL Toxav_Call_Control;

//!TOKSTYLE+

#endif // C_TOXCORE_TOXAV_TOXAV_H
%}