n_alAudioFrame

Syntax

#include <n_libaudio.h>
Acmd *n_alAudioFrame(Acmd *cmdList, s32 *cmdLen, s16 *outBuf, s32 outLen);

Arguments

• cmdList is the pointer to the location to start writing the audio command list
• cmdLen is the pointer to the location to write the length of the command list generated by the function
• outBuf is the pointer to the DRAM location where the audio microcode, when executing the generated audio command list, is to write the synthesized audio samples
• outLen is the number of stereo samples that the audio command list is to generate.

Explanation
This function is available in the n_audio library. It generates an audio command list that, when executed on the RSP, puts a buffer of outLen-synthesized stereo samples at the DRAM location specified by outBuf.

An audio command list is a sequence of commands or directions that is interpreted by the RSP audio microcode as describing how audio is to be synthesized. The outBuf should contain four bytes for each sample requested by outLen because stereo 16-bit samples are generated. The n_alAudioFrame function writes the length, in number of RSP commands (each eight bytes long), of the command list it generates to the signed 32-bit value pointed to by the cmdLen argument. It also returns a pointer to the next available command list location.

If there are no players associated with the synthesizer, n_alAudioFrame sets cmdLen to zero and the application should not send the task to the RSP.

Note that n_alAudioFrame does not actually cause the command list to be executed.

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