al_create_sample - Man Page

#include <allegro5/allegro_audio.h>

ALLEGRO_SAMPLE *al_create_sample(void *buf, unsigned int samples,
   unsigned int freq, ALLEGRO_AUDIO_DEPTH depth,
   ALLEGRO_CHANNEL_CONF chan_conf, bool free_buf)

Create a sample data structure from the supplied buffer. If free_buf is true then the buffer will be freed with al_free(3) when the sample data structure is destroyed. For portability (especially Windows), the buffer should have been allocated with al_malloc(3). Otherwise you should free the sample data yourself.

A sample that is referred to by the samples parameter refers to a sequence channel intensities. E.g. if you’re making a stereo sample with the samples set to 4, then the layout of the data in buf will be:

LRLRLRLR

Where L and R are the intensities for the left and right channels respectively. A single sample, then, refers to the LR pair in this example.

To allocate a buffer of the correct size, you can use something like this:

int sample_size = al_get_channel_count(chan_conf)
                  * al_get_audio_depth_size(depth);
int bytes = samples * sample_size;
void *buffer = al_malloc(bytes);

al_destroy_sample(3), ALLEGRO_AUDIO_DEPTH(3), ALLEGRO_CHANNEL_CONF(3)

al_get_sample(3).