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

269 строки
8.7 KiB
C

/*
* 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;
/** 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);
/** 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 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 samplerate 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 ms
@retval CUBEB_OK
@retval CUBEB_ERROR */
int cubeb_stream_get_latency(cubeb_stream * stream, uint32_t * latency);
#if defined(__cplusplus)
}
#endif
#endif /* CUBEB_c2f983e9_c96f_e71c_72c3_bbf62992a382 */