gecko-dev/media/libcubeb/include/cubeb.h

/*
 * Copyright © 2011 Mozilla Foundation
 *
 * This program is made available under an ISC-style license.  See the
 * accompanying file LICENSE for details.
 */
#if !defined(CUBEB_c2f983e9_c96f_e71c_72c3_bbf62992a382)
#define CUBEB_c2f983e9_c96f_e71c_72c3_bbf62992a382

#include <cubeb/cubeb-stdint.h>

#if defined(__cplusplus)
extern "C" {
#endif

/** @mainpage

    @section intro Introduction

    This is the documentation for the <tt>libcubeb</tt> C API.
    <tt>libcubeb</tt> is a callback-based audio API library allowing the
    authoring of portable multiplatform audio playback.

    @section example Example code

    @code
    cubeb * app_ctx;
    cubeb_init(&app_ctx, "Example Application");

    cubeb_stream_params params;
    params.format = CUBEB_SAMPLE_S16NE;
    params.rate = 48000;
    params.channels = 2;

    unsigned int latency_ms = 250;

    cubeb_stream * stm;
    cubeb_stream_init(app_ctx, &stm, "Example Stream 1", params,
                      latency_ms, data_cb, state_cb, NULL);

    cubeb_stream_start(stm);
    for (;;) {
      cubeb_stream_get_position(stm, &ts);
      printf("time=%llu\n", ts);
      sleep(1);
    }
    cubeb_stream_stop(stm);

    cubeb_stream_destroy(stm);
    cubeb_destroy(app_ctx);
    @endcode

    @code
    long data_cb(cubeb_stream * stm, void * user, void * buffer, long nframes)
    {
      short * buf = buffer;
      for (i = 0; i < nframes; ++i) {
        for (c = 0; c < params.channels; ++c) {
          buf[i][c] = 0;
        }
      }
      return nframes;
    }
    @endcode

    @code
    void state_cb(cubeb_stream * stm, void * user, cubeb_state state)
    {
      printf("state=%d\n", state);
    }
    @endcode
*/

/** @file
    The <tt>libcubeb</tt> C API. */

typedef struct cubeb cubeb;               /**< Opaque handle referencing the application state. */
typedef struct cubeb_stream cubeb_stream; /**< Opaque handle referencing the stream state. */

/** Sample format enumeration. */
typedef enum {
  /**< Little endian 16-bit signed PCM. */
  CUBEB_SAMPLE_S16LE,
  /**< Big endian 16-bit signed PCM. */
  CUBEB_SAMPLE_S16BE,
  /**< Little endian 32-bit IEEE floating point PCM. */
  CUBEB_SAMPLE_FLOAT32LE,
  /**< Big endian 32-bit IEEE floating point PCM. */
  CUBEB_SAMPLE_FLOAT32BE,
#if defined(WORDS_BIGENDIAN) || defined(__BIG_ENDIAN__)
  /**< Native endian 16-bit signed PCM. */
  CUBEB_SAMPLE_S16NE = CUBEB_SAMPLE_S16BE,
  /**< Native endian 32-bit IEEE floating point PCM. */
  CUBEB_SAMPLE_FLOAT32NE = CUBEB_SAMPLE_FLOAT32BE
#else
  /**< Native endian 16-bit signed PCM. */
  CUBEB_SAMPLE_S16NE = CUBEB_SAMPLE_S16LE,
  /**< Native endian 32-bit IEEE floating point PCM. */
  CUBEB_SAMPLE_FLOAT32NE = CUBEB_SAMPLE_FLOAT32LE
#endif
} cubeb_sample_format;

#if defined(__ANDROID__)
typedef enum {
    CUBEB_STREAM_TYPE_VOICE_CALL = 0,
    CUBEB_STREAM_TYPE_SYSTEM = 1,
    CUBEB_STREAM_TYPE_RING = 2,
    CUBEB_STREAM_TYPE_MUSIC = 3,
    CUBEB_STREAM_TYPE_ALARM = 4,
    CUBEB_STREAM_TYPE_NOTIFICATION = 5,
    CUBEB_STREAM_TYPE_BLUETOOTH_SCO = 6,
    CUBEB_STREAM_TYPE_SYSTEM_ENFORCED = 7,
    CUBEB_STREAM_TYPE_DTMF = 8,
    CUBEB_STREAM_TYPE_TTS = 9,
    CUBEB_STREAM_TYPE_FM = 10,

    CUBEB_STREAM_TYPE_MAX
} cubeb_stream_type;
#endif

/** Stream format initialization parameters. */
typedef struct {
  cubeb_sample_format format; /**< Requested sample format.  One of
                                   #cubeb_sample_format. */
  unsigned int rate;          /**< Requested sample rate.  Valid range is [1, 192000]. */
  unsigned int channels;      /**< Requested channel count.  Valid range is [1, 32]. */
#if defined(__ANDROID__)
  cubeb_stream_type stream_type; /**< Used to map Android audio stream types */
#endif
} cubeb_stream_params;

/** Output device description */
typedef struct {
  char * output_name; /**< The name of the output device */
  char * input_name; /**< The name of the input device */
} cubeb_device;

/** Stream states signaled via state_callback. */
typedef enum {
  CUBEB_STATE_STARTED, /**< Stream started. */
  CUBEB_STATE_STOPPED, /**< Stream stopped. */
  CUBEB_STATE_DRAINED, /**< Stream drained. */
  CUBEB_STATE_ERROR    /**< Stream disabled due to error. */
} cubeb_state;

/** Result code enumeration. */
enum {
  CUBEB_OK = 0,                       /**< Success. */
  CUBEB_ERROR = -1,                   /**< Unclassified error. */
  CUBEB_ERROR_INVALID_FORMAT = -2,    /**< Unsupported #cubeb_stream_params requested. */
  CUBEB_ERROR_INVALID_PARAMETER = -3  /**< Invalid parameter specified. */
};

/** User supplied data callback.
    @param stream
    @param user_ptr
    @param buffer
    @param nframes
    @retval Number of frames written to buffer, which must equal nframes except at end of stream.
    @retval CUBEB_ERROR on error, in which case the data callback will stop
            and the stream will enter a shutdown state. */
typedef long (* cubeb_data_callback)(cubeb_stream * stream,
                                     void * user_ptr,
                                     void * buffer,
                                     long nframes);

/** User supplied state callback.
    @param stream
    @param user_ptr
    @param state */
typedef void (* cubeb_state_callback)(cubeb_stream * stream,
                                      void * user_ptr,
                                      cubeb_state state);

/**
 * User supplied callback called when the underlying device changed.
 * @param user */
typedef void (* cubeb_device_changed_callback)(void * user_ptr);

/** Initialize an application context.  This will perform any library or
    application scoped initialization.
    @param context
    @param context_name
    @retval CUBEB_OK
    @retval CUBEB_ERROR */
int cubeb_init(cubeb ** context, char const * context_name);

/** Get a read-only string identifying this context's current backend.
    @param context
    @retval Read-only string identifying current backend. */
char const * cubeb_get_backend_id(cubeb * context);

/** Get the maximum possible number of channels.
    @param context
    @param max_channels The maximum number of channels.
    @retval CUBEB_OK
    @retval CUBEB_ERROR_INVALID_PARAMETER
    @retval CUBEB_ERROR */
int cubeb_get_max_channel_count(cubeb * context, uint32_t * max_channels);

/** Get the minimal latency value, in milliseconds, that is guaranteed to work
    when creating a stream for the specified sample rate. This is platform and
    backend dependant.
    @param context
    @param params On some backends, the minimum achievable latency depends on
                  the characteristics of the stream.
    @param latency_ms The latency value, in ms, to pass to cubeb_stream_init.
    @retval CUBEB_ERROR_INVALID_PARAMETER
    @retval CUBEB_OK */
int cubeb_get_min_latency(cubeb * context, cubeb_stream_params params, uint32_t * latency_ms);

/** Get the preferred sample rate for this backend: this is hardware and platform
   dependant, and can avoid resampling, and/or trigger fastpaths.
   @param context
   @param rate The samplerate (in Hz) the current configuration prefers.
   @return CUBEB_ERROR_INVALID_PARAMETER
   @return CUBEB_OK */
int cubeb_get_preferred_sample_rate(cubeb * context, uint32_t * rate);

/** Destroy an application context.
    @param context */
void cubeb_destroy(cubeb * context);

/** Initialize a stream associated with the supplied application context.
    @param context
    @param stream
    @param stream_name
    @param stream_params
    @param latency Approximate stream latency in milliseconds.  Valid range is [1, 2000].
    @param data_callback Will be called to preroll data before playback is
                          started by cubeb_stream_start.
    @param state_callback
    @param user_ptr
    @retval CUBEB_OK
    @retval CUBEB_ERROR
    @retval CUBEB_ERROR_INVALID_FORMAT */
int cubeb_stream_init(cubeb * context, cubeb_stream ** stream, char const * stream_name,
                      cubeb_stream_params stream_params, unsigned int latency,
                      cubeb_data_callback data_callback,
                      cubeb_state_callback state_callback,
                      void * user_ptr);

/** Destroy a stream.
    @param stream */
void cubeb_stream_destroy(cubeb_stream * stream);

/** Start playback.
    @param stream
    @retval CUBEB_OK
    @retval CUBEB_ERROR */
int cubeb_stream_start(cubeb_stream * stream);

/** Stop playback.
    @param stream
    @retval CUBEB_OK
    @retval CUBEB_ERROR */
int cubeb_stream_stop(cubeb_stream * stream);

/** Get the current stream playback position.
    @param stream
    @param position Playback position in frames.
    @retval CUBEB_OK
    @retval CUBEB_ERROR */
int cubeb_stream_get_position(cubeb_stream * stream, uint64_t * position);

/** Get the latency for this stream, in frames. This is the number of frames
    between the time cubeb acquires the data in the callback and the listener
    can hear the sound.
    @param stream
    @param latency Current approximate stream latency in frames.
    @retval CUBEB_OK
    @retval CUBEB_ERROR */
int cubeb_stream_get_latency(cubeb_stream * stream, uint32_t * latency);

/**
 * Set the volume for a stream.
 * @param stream the stream for which to adjust the volume.
 * @param volume a float between 0.0 (muted) and 1.0 (maximum volume)
 * @return CUBEB_ERROR_INVALID_PARAMETER if volume is outside [0.0; 1.0]
 * @return CUBEB_ERROR_INVALID_PARAMETER if stream is an invalid pointer
 * @return CUBEB_OK otherwise
 */
int cubeb_stream_set_volume(cubeb_stream * stream, float volume);

/**
 * If the stream is stereo, set the left/right panning. If the stream is mono,
 * this has no effect.
 * @param stream the stream for which to change the panning
 * @param panning a number from -1.0 to 1.0. -1.0 means that the stream is fully
 * mixed in the left channel, 1.0 means the stream is fully mixed in the right
 * channel. 0.0 is equal power in the right and left channel (default).
 * @return CUBEB_ERROR_INVALID_PARAMETER if stream is null or if panning is outside
 * the [-1.0; 1.0] range.
 * @return CUBEB_ERROR if this stream is not mono nor stereo.
 * @return CUBEB_OK otherwise.
 */
int cubeb_stream_set_panning(cubeb_stream * stream, float panning);

/**
 * Get the current output device for this stream.
 * @param stm the stream for which to query the current output device
 * @param device a pointer in which the current output device will be stored.
 * @return CUBEB_OK in case of success
 * @return CUBEB_ERROR_INVALID_PARAMETER if either stm, device or count are
 *         invalid pointers
 */
int cubeb_stream_get_current_device(cubeb_stream * stm,
                                    cubeb_device ** const device);

/**
 * Destroy a cubeb_device structure.
 * @param stream the stream passed in cubeb_stream_get_current_device
 * @param devices the devices to destroy
 * @return CUBEB_OK in case of success
 * @return CUBEB_ERROR_INVALID_PARAMETER if devices is an invalid pointer
 */
int cubeb_stream_device_destroy(cubeb_stream * stream,
                                cubeb_device * devices);

/**
 * Set a callback to be notified when the output device changes.
 * @param stream the stream for which to set the callback.
 * @param device_changed_callback a function called whenever the device has
 *        changed. Passing NULL allow to unregister a function
 * @return CUBEB_ERROR_INVALID_PARAMETER if either stream or
 *         device_changed_callback are invalid pointers.
 * @return CUBEB_OK
 */
int cubeb_stream_register_device_changed_callback(cubeb_stream * stream,
                                                  cubeb_device_changed_callback  device_changed_callback);

#if defined(__cplusplus)
}
#endif

#endif /* CUBEB_c2f983e9_c96f_e71c_72c3_bbf62992a382 */