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- (6) ADPCM compatible
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- Link the ADPCM decompression library SEGA_ADP.LIB.
Call the ADPCM usage declaration PCM_DeclareUseAdpcm after the - initialization function.
◆ Playback of specified ADPCM format
- You can play in exactly the same procedure (same program) as AIFF format. However, please note that the CPU load is higher than in AIFF format.
◆ CD-ROM XA Audio format playback
- The library determines the playback frequency and the number of channels (stereo / mono) from the coding information in the subheader area. Make sure it is written correctly.
The - stream key is set by the library user.
- Make the ring buffer an integral multiple of the sector size 2324 bytes.
Set playback information with - PCM_SetInfo.
- CD_ROM XA Audio playback can only be used in stream playback mode.
- Please refer to the sample program smppcm5.c.
- (7) How to use the function
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- Be sure to call PCM_Init at the beginning of the program.
Be sure to call PCM_VblIn within a - V blank IN interrupt.
- PCM_Start can only be executed once for a handle.
If you want to play the same file over and over again, create a handle each time.
Call - PCM_SetLoadNum, PCM_SetPcmCmdBlockNo, and PCM_SetPcmStreamNo before starting playback.
- Be sure to use PCM_NotifyWriteSize for the handle created by PCM_CreateMemHandle to notify the data supply amount to the ring buffer.
- When using the pause function, it is necessary to specify the work for pause processing in advance with PCM_SetPauseWork. This work need not be prepared for each handle.
Since this work is a work area that is temporarily used in the pause-on process, you can reserve the area immediately before the pause-on process and release the area immediately after.
- Data transfer method from CD block to ring buffer By default, data is transferred by CPU DMA.
PCM_SetTrModeCd can be used to specify program transfer, CPU DMA, or SCU DMA.
Call PCM_SetTrModeCd before calling the task function for the first time after creating the handle.
- When playing CD-ROM XA Audio, be sure to set the playback information with PCM_SetInfo.
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