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ALLEGRO_AUDIO_STREAM(3) Library Functions Manual ALLEGRO_AUDIO_STREAM(3) NAME ALLEGRO_AUDIO_STREAM - Allegro 5 API SYNOPSIS #include <allegro5/allegro_audio.h> typedef struct ALLEGRO_AUDIO_STREAM ALLEGRO_AUDIO_STREAM; DESCRIPTION An ALLEGRO_AUDIO_STREAM object is used to stream generated audio to the sound device, in real-time. This is done by reading from a buffer, which is split into a number of fragments. Whenever a fragment has finished playing, the user can refill it with new data. As with ALLEGRO_SAMPLE_INSTANCE(3) objects, streams store information nec- essary for playback, so you may not play the same stream multiple times si- multaneously. Streams also need to be attached to an ALLEGRO_MIXER(3), which, eventually, reaches an ALLEGRO_VOICE(3) object. While playing, you must periodically fill fragments with new audio data. To know when a new fragment is ready to be filled, you can either directly check with al_get_available_audio_stream_fragments(3), or listen to events from the stream. You can register an audio stream event source to an event queue; see al_get_audio_stream_event_source(3). An ALLEGRO_EVENT_AUDIO_STREAM_FRAG- MENT(3) event is generated whenever a new fragment is ready. When you re- ceive an event, use al_get_audio_stream_fragment(3) to obtain a pointer to the fragment to be filled. The size and format are determined by the para- meters passed to al_create_audio_stream(3). If you're late with supplying new data, the stream will be silent until new data is provided. You must call al_drain_audio_stream(3) when you're fin- ished with supplying data to the stream. It is often a good idea to prefill the audio stream with data before ALLE- GRO_EVENT_AUDIO_STREAM_FRAGMENT(3) events arrive. Here is a snippet that will fill the stream buffers with silence: ALLEGRO_AUDIO_STREAM *stream = al_create_audio_stream(num_buffers, samples_per_buffer, freq, depth, channel_conf); void *buf; while ((buf = al_get_audio_stream_fragment(stream))) { al_fill_silence(buf, samples_per_buffer, depth, channel_conf); al_set_audio_stream_fragment(stream, buf); } If the stream is created by al_load_audio_stream(3) or al_play_au- dio_stream(3) then it will also generate an ALLEGRO_EVENT_AUDIO_STREAM_FIN- ISHED(3) event if it reaches the end of the file and is not set to loop. Allegro reference manual ALLEGRO_AUDIO_STREAM(3)
NAME | SYNOPSIS | DESCRIPTION
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