int mp4_set_sample_position(struct mp4 *f, uint32_t sample);
int mp4_open_read(const struct mp4_callback *cb, struct mp4 **result);
void mp4_close(struct mp4 *f);
-int32_t mp4_get_sample_size(const struct mp4 *f, int sample);
+int mp4_get_sample_size(const struct mp4 *f, uint32_t sample, uint32_t *result);
uint32_t mp4_get_sample_rate(const struct mp4 *f);
uint32_t mp4_get_channel_count(const struct mp4 * f);
int32_t mp4_num_samples(const struct mp4 *f);