3. Playback procedure

(1) Playback procedure

Figure 3.1 shows the procedure for playing back using the stream system.

Figure 3.1 Playback procedure during stream playback

(2) Program example

The following is an example program that uses a stream system to play AIFF or APCM format files.

	#define RING_BUF_SIZE (2048L * 10)
	#define PCM_ADDR ((void *) 0x25a20000)
	#define PCM_SIZE (4096L * 2)

	/* work */
	PcmWork pcm_work;

	/ * Ring buffer * /
	Uint32 ring_buf [RING_BUF_SIZE / sizeof (Uint32)];
	StmHn stm;
	PcmHn pcm;

	/ * Sound initialization * /
	SND_Init (･ ･);

	/* Initialize */
	PCM_Init ();

	/ * Declaration of use of ADPCM (required when using ADPCM) * /
	PCM_DeclareUseAdpcm ();

	/ * Interrupt processing settings * /
Use INT_ ??? to set the V blank IN interrupt.
Call PCM_VblIn (); in the V-blank IN interrupt.

	/ * File initialization * /
	GFS_Init (･ ･);
	STM_Init (･ ･);
	STM_OpenGrp ();
	STM_SetExecGrp (･ ･);
	/ * Open stream * /
	stm = STM_OpenFid (･ ･);

	/ * Handle generation * /
	PCM_PARA_WORK (& para) = & pcm_work;
	PCM_PARA_RING_ADDR (& para) = ring_buf;
	PCM_PARA_RING_SIZE (& para) = RING_BUF_SIZE;
	PCM_PARA_PCM_ADDR (& para) = PCM_ADDR;
	PCM_PARA_PCM_SIZE (& para) = PCM_SIZE;
	pcm = PCM_CreateStmHandle (& para, stm);

	/ * Start playback * /
	PCM_Start (pcm);
	while (TRUE) {
                / * Run server * /
                STM_ExecServer ();

		/ * Playback task processing * /
		PCM_Task (pcm);

		/ * End judgment * /
		if (PCM_GetPlayStatus (pcm) == PCM_STAT_PLAY_END) break;
	}
	/ * Abandonment of handle * /
	PCM_DestroyStmHandle (pcm);

	/ * Close stream * /
	STM_Close (stm);

    /* End processing */
       PCM_Finish ();