void freeDecoder(void)
{
MP3FreeDecoder(mdecoder);
fclose(fp);
fp = NULL;
firstFrame = 0;
fileSize = 0;
}
void mp3_decoder_detach(struct mp3_decoder* decoder)
{
RT_ASSERT(decoder != RT_NULL);
/* close audio device */
if (decoder->snd_device != RT_NULL)
rt_device_close(decoder->snd_device);
/* release mp3 decoder */
MP3FreeDecoder(decoder->decoder);
}
int Mp3Decode(const char* pszFile)
{
int nResult = 0;
BYTE* pInData = g_Mp3InBuffer;
UINT unInDataLeft = 0;
FIL fIn;
UINT bEof = FALSE;
UINT bOutOfData = FALSE;
MP3FrameInfo mp3FrameInfo;
uint32_t unDmaBufMode = 0;
g_pMp3DmaBufferPtr = g_pMp3DmaBuffer;
g_pMp3DecoderThread = chThdSelf();
FRESULT errFS = f_open(&fIn, pszFile, FA_READ);
if(errFS != FR_OK)
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: Failed to open file \"%s\" for reading, err=%d\r\n", pszFile, errFS);
return -1;
}
HMP3Decoder hMP3Decoder = MP3InitDecoder();
if(hMP3Decoder == NULL)
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: Failed to initialize mp3 decoder engine\r\n");
return -2;
}
chprintf((BaseChannel*)&SD2, "Mp3Decode: Start decoding \"%s\"\r\n", pszFile);
char szArtist[80];
char szTitle[80];
palSetPad(GPIOD, 12); // green LED
Mp3ReadId3V2Tag(&fIn, szArtist, sizeof(szArtist), szTitle, sizeof(szTitle));
palClearPad(GPIOD, 12); // green LED
if(szArtist[0] != 0 || szTitle[0] != 0)
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: Now playing (ID3v2): %s - %s\r\n", szArtist, szTitle);
}
int nDecodeRes = ERR_MP3_NONE;
UINT unFramesDecoded = 0;
do
{
if(unInDataLeft < (2 * MAINBUF_SIZE) && (!bEof))
{
UINT unRead = Mp3FillReadBuffer(pInData, unInDataLeft, &fIn);
unInDataLeft += unRead;
pInData = g_Mp3InBuffer;
if(unRead == 0)
{
bEof = 1;
}
}
// find start of next MP3 frame - assume EOF if no sync found
int nOffset = MP3FindSyncWord(pInData, unInDataLeft);
if(nOffset < 0)
{
bOutOfData = TRUE;
break;
}
pInData += nOffset;
unInDataLeft -= nOffset;
// decode one MP3 frame - if offset < 0 then bytesLeft was less than a full frame
nDecodeRes = MP3Decode(hMP3Decoder, &pInData, (int*)&unInDataLeft, (short*)g_pMp3OutBuffer, 0);
switch(nDecodeRes)
{
case ERR_MP3_NONE:
{
MP3GetLastFrameInfo(hMP3Decoder, &mp3FrameInfo);
if(unFramesDecoded == 0)
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: %d Hz %d Bit %d Channels\r\n",
mp3FrameInfo.samprate, mp3FrameInfo.bitsPerSample, mp3FrameInfo.nChans);
if((mp3FrameInfo.samprate > 48000) || (mp3FrameInfo.bitsPerSample != 16) || (mp3FrameInfo.nChans != 2))
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: incompatible MP3 file.\r\n");
nResult = -5;
break;
}
}
if((unFramesDecoded) % 100 == 0)
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: frame %u, bitrate=%d\r\n", unFramesDecoded, mp3FrameInfo.bitrate);
}
unFramesDecoded++;
g_pMp3OutBufferPtr = g_pMp3OutBuffer;
uint32_t unOutBufferAvail= mp3FrameInfo.outputSamps;
while(unOutBufferAvail > 0)
{
// fill up the whole dma buffer
uint32_t unDmaBufferSpace = 0;
if(unDmaBufMode == 0)
{
// fill the whole buffer
// dma buf ptr was reset to beginning of the buffer
unDmaBufferSpace = g_pMp3DmaBuffer + MP3_DMA_BUFFER_SIZE - g_pMp3DmaBufferPtr;
}
else if(unDmaBufMode == 1)
{
// fill the first half of the buffer
// dma buf ptr was reset to beginning of the buffer
unDmaBufferSpace = g_pMp3DmaBuffer + (MP3_DMA_BUFFER_SIZE / 2) - g_pMp3DmaBufferPtr;
}
else
{
// fill the last half of the buffer
// dma buf ptr was reset to middle of the buffer
unDmaBufferSpace = g_pMp3DmaBuffer + MP3_DMA_BUFFER_SIZE - g_pMp3DmaBufferPtr;
}
uint32_t unCopy = unDmaBufferSpace > unOutBufferAvail ? unOutBufferAvail : unDmaBufferSpace;
if(unCopy > 0)
{
memcpy(g_pMp3DmaBufferPtr, g_pMp3OutBufferPtr, unCopy * sizeof(uint16_t));
unOutBufferAvail -= unCopy;
g_pMp3OutBufferPtr += unCopy;
unDmaBufferSpace -= unCopy;
g_pMp3DmaBufferPtr += unCopy;
}
if(unDmaBufferSpace == 0)
{
// dma buffer full
// see if this was the first run
if(unDmaBufMode == 0)
{
// on the first buffer fill up,
// start the dma transfer
if(EVAL_AUDIO_Init(OUTPUT_DEVICE_HEADPHONE, 80, (uint32_t)mp3FrameInfo.samprate))
{
chprintf((BaseChannel *) &SD2, "Mp3Decode: audio init failed\r\n");
nResult = -4;
break;
}
EVAL_AUDIO_Play(g_pMp3DmaBuffer, MP3_DMA_BUFFER_SIZE * sizeof(uint16_t));
}
// we must wait for the dma stream tx interrupt here
eventmask_t em = chEvtWaitAny((eventmask_t)2 | 4 | 8);
if(em & 8)
{
// stop requested
chprintf((BaseChannel*)&SD2, "Mp3Decode: Stop requested\r\n");
nResult = 1;
break;
}
if((em & 2) && (em & 4))
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: DMA out of sync (HT and TC both set)\r\n");
nResult = -3;
break;
}
if(unDmaBufMode == 0 || unDmaBufMode == 2)
{
// the dma event we expect is "half transfer" (=2)
if(em & 2)
{
// set up first half mode
unDmaBufMode = 1;
g_pMp3DmaBufferPtr = g_pMp3DmaBuffer;
}
else
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: DMA out of sync (expected HT, got TC)\r\n");
nResult = -3;
break;
}
}
else
{
// the dma event we expect is "transfer complete" (=4)
if(em & 4)
{
// set up last half mode
unDmaBufMode = 2;
g_pMp3DmaBufferPtr = g_pMp3DmaBuffer + (MP3_DMA_BUFFER_SIZE / 2);
}
else
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: DMA out of sync (expected TC, got HT)\r\n");
nResult = -3;
}
}
}
}
break;
}
case ERR_MP3_MAINDATA_UNDERFLOW:
{
// do nothing - next call to decode will provide more mainData
break;
}
case ERR_MP3_FREE_BITRATE_SYNC:
{
break;
}
case ERR_MP3_INDATA_UNDERFLOW:
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: Decoding error ERR_MP3_INDATA_UNDERFLOW\r\n");
bOutOfData = TRUE;
break;
}
default:
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: Decoding error %d\r\n", nDecodeRes);
bOutOfData = TRUE;
break;
}
}
}
while((!bOutOfData) && (nResult == 0));
chprintf((BaseChannel*)&SD2, "Mp3Decode: Finished decoding\r\n");
MP3FreeDecoder(hMP3Decoder);
if(EVAL_AUDIO_Stop(CODEC_PDWN_HW))
{
chprintf((BaseChannel*)&SD2, "Mp3Decode: Failed to stop audio\r\n");
}
EVAL_AUDIO_DeInit();
f_close(&fIn);
// this is the only legit way I know
// to remvove still pending event flags
// from the thread
chEvtWaitOneTimeout(2, 50);
chEvtWaitOneTimeout(4, 50);
return nResult;
}
void labor6(void) {
run = 1;
syncword_address =0;
spi_address = 0;
pwmVal = 0;
HMP3Decoder mp3dec;
bytesLeft = 0;
bytesTilSyncWord = 0;
decodeRetVal = 0;
errorCounter = 0;
idx_ISR = 0;
mainBuf_empty = 1;
interrupt_Counter = 0;
mseczaehlvar = 0;
RCC_ClocksTypeDef RCC_Clocks;
msec = 0;
int i = 0;
//Amplitude 1.0V (b_big)
amplitude = b_big;
spi_setup();
setup_TIM8_DAC_PWM();
mp3dec = MP3InitDecoder();
//SysTick end of count event each 10ms
RCC_GetClocksFreq(&RCC_Clocks);
SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);
TFT_cursor_off();
buf1.isEmpty = 1;
buf2.isEmpty = 1;
mp3OutBuffer = &buf1; //start with buf1
irsInBuffer = &buf1;
TFT_cls();
TFT_gotoxy(1,1);
TFT_puts("Frequenz: 5000");
while(B1 != 0 && B2 != 0) {}
do {
//Check Buttons
read_buttons();
//ausgabe
print_display();
//wenn der mainBuf leer ist, muss der durch readSPI mit mp3-daten gefuellt werden
if (mainBuf_empty) {
do {
//Shift bytes to the beginning
/**
* Bsp: mainBufSize = 10
* readBytes = 7 --> bytesLeft = 3
* for(){
* mainBuffer[0] = mainBuffer[(10-3)+0] idx[0] = idx[7]
* mainBuffer[1] = mainBuffer[(10-3)+1] idx[1] = ide[8] ...
*/
for(i = 0; i < bytesLeft; i++) { //die ungelesene bytes am anfang stellen
mainBuf[i] = mainBuf[(MAINBUF_SIZE - bytesLeft) + i];
}
//Reads size-bytes from current_SPI_Address and writes them into the given array ((mainBuffer + nBytesLeft))
//also nach diesem aufruf, ist der mainBuf voll und spiadresse muss verschoben werden
spiFlashMemRead(SPI_MEM_WORK, spi_address, (mainBuf + bytesLeft), MAINBUF_SIZE - bytesLeft);
//nach sync word in dem mainBuf suchen
bytesTilSyncWord = MP3FindSyncWord(mainBuf, MAINBUF_SIZE);
if (bytesTilSyncWord == 0) { //falls guelltige date gleich am anfang liegen
spi_address = spi_address + (MAINBUF_SIZE - bytesLeft);
} else if (bytesTilSyncWord < 0) {//fehler, kein sync word gefunden
run = 0;
} else if (bytesTilSyncWord > 0) {//falls skip word an der n-te adresse gefunden wurde, verschiebe ich die spiadresse um n, damit ich beim naechsten durchlauf vom flash nur die guelltige daten lese (also muell ueberspringen)
spi_address = (spi_address - bytesLeft )+ bytesTilSyncWord;
}
bytesLeft = 0; //MUSS DAS HIER NICHT AUSSERHALB DER WHILE ?? DAMIT DIE NBYTES NICHT VERLOREN GEHEN
} while(bytesTilSyncWord != 0 && run);
mainBuf_empty = 0; //mainBuf ist voll
}
if (run) { //wenn kein fehler
//wenn der mp3OutBuf voll ist ODER der MainBuf leer ist, dann warten (WAITING-LED) anschalten
if (!mp3OutBuffer->isEmpty || mainBuf_empty) {
setLED(WAITING_LED);
} else {
resetLED(WAITING_LED);
bytesLeft = MAINBUF_SIZE; //in nBytesLeft steht wieviele daten aus dem MainBuf noch in dem mp3OutBuf uebertragen werden muessen
ptrMainBuf = mainBuf; //mainBufPointer soll auf MainBuff zeigen, obwohl es bei der initialisierung schon gemacht wurde !!
/**
* para1: decoder instance
* para2: buffer aus dem die daten decodet werden sollen
* para3: (input) --> anzahl gueltige bytes, die gelesen werden sollen,
* (output)--> input - gelesene bytes, also die bytes die noch gelesen werden muessen
* para4: der buffer in dem geschrieben werden soll, der pointer wird geupdatet (bis wo der voll geschrieben wurde)
*/
//nach diesem aufruf ist der mp3OutBuf auf jeden fall voll
decodeRetVal = MP3Decode(mp3dec, &ptrMainBuf, &bytesLeft, mp3OutBuffer->data, 0); //decodeResult -->(0 means no error, < 0 means error)
mainBuf_empty = 1; //der mainBuf ist nicht komplett voll
if (decodeRetVal < 0) {
errorCounter++;
} else {
errorCounter = 0;
}
if (errorCounter > 2) { //fehler beim decode aufgetreten
run = 0;
} else {
mp3OutBuffer->isEmpty = 0; //der mp3OutBuffer wurde voll geschrieben, bereit fuer die ISR
if(mp3OutBuffer == &buf1) { //buffer ist voll, also wechseln
mp3OutBuffer = &buf2;
} else if (mp3OutBuffer == &buf2) {
mp3OutBuffer = &buf1;
}
}
}
}
} while (run);
MP3FreeDecoder(mp3dec);
}
static void play_mp3(char* filename) {
bool out_of_data;
int cc;
// Open file
if (FR_OK == f_open(&file, filename, FA_OPEN_EXISTING | FA_READ)) {
// Read ID3v2 Tag
char szArtist[120];
char szTitle[120];
Mp3ReadId3V2Tag(&file, szArtist, sizeof(szArtist), szTitle, sizeof(szTitle));
///////////////////////////////////////////////////////////buffer starts getting filled for first time
// Start Initial fill of buffer
hMP3Decoder = MP3InitDecoder();
out_of_data = fill_mp3_buffer(&file,0,true);
for (cc = 1 ; cc < NUMBER_BUFFERS ; cc++ ) {
if ( out_of_data ) {
break;
}
out_of_data = fill_mp3_buffer(&file,cc,false);
}
// Initialize buffer counters
buffer_read = 0;
buffer_write = 0;
/////////////////////////////////////////////////////////////////////////////////////////
// Play mp3
running_player = true;
InitializeAudio(Audio44100HzSettings);
// InitializeAudio(Audio32000HzSettings);
SetAudioVolume(0xAF);
PlayAudioWithCallback(AudioCallback, 0);
//////////////////////////////////////////////////////////////////////////////////////////
for(;;) {
/*
* If we have an unused buffer, call fill_mp3_buffer to fill it.
*/
if ( buffer_read != buffer_write ) {
// Refill the MP3 buffer
out_of_data = fill_mp3_buffer(&file,buffer_write,false);
if ( !out_of_data ) {
buffer_write = ( buffer_write + 1 ) % NUMBER_BUFFERS;
}
// Out of data or error or user button... Stop playback!
if (out_of_data || (exitMp3 == 1))
{
StopAudio();
running_player = false;
// Re-initialize and set volume to avoid noise
InitializeAudio(Audio44100HzSettings);
SetAudioVolume(0);
// Close currently open file
f_close(&file);
MP3FreeDecoder(hMP3Decoder);
return;
}
}
else {
// We don't have any work to do, shut down until interrupt (DMA transfer complete)
__asm__ volatile ("wfi");
}
}
}
int decoderMain(chanend pcmChan, chanend rxChan, chanend mp3Reset)
{
int bytesLeft, nRead, err, offset, outOfData, eofReached, nFrames;
int reset;
unsigned char readBuf[READBUF_SIZE], *readPtr;
// unsigned char mp3_data
// short outBuf[MAX_NCHAN * MAX_NGRAN * MAX_NSAMP];
// short outBuf[256];
MP3FrameInfo mp3FrameInfo;
HMP3Decoder hMP3Decoder;
if ( (hMP3Decoder = MP3InitDecoder()) == 0 )
{
return -2;
// puts("Init died");
}
bytesLeft = 0;
outOfData = 0;
eofReached = 0;
readPtr = readBuf;
nRead = 0;
nFrames = 0;
do
{
bytesLeft = RxNewFrame(readBuf, READBUF_SIZE, rxChan, mp3Reset);
if (bytesLeft == 0)
{
break;
}
readPtr = readBuf;
/* decode one MP3 frame - if offset < 0 then bytesLeft was less than a full frame */
err = MP3Decode(hMP3Decoder, &readPtr, &bytesLeft, NULL, 1, pcmChan);
// err = MP3Decode(hMP3Decoder, &readPtr, &bytesLeft, NULL, 0, pcmChan);
nFrames++;
// printintln(nFrames);
// Need to flush the PCM buffer for next frame decode
// By outputting all ones to the channel
// OutputToPCMBuf(0xffff, 0xffff, pcmChan);
if (err)
{
/* error occurred */
switch (err)
{
case ERR_MP3_INDATA_UNDERFLOW:
printstrln("HERE");
outOfData = 1;
break;
case ERR_MP3_MAINDATA_UNDERFLOW:
/* do nothing - next call to decode will provide more mainData */
break;
case ERR_MP3_FREE_BITRATE_SYNC:
default:
outOfData = 1;
// printintln(err);
// printstrln("\nHERE2");
// while (1);
break;
}
}
else
{
/* no error */
MP3GetLastFrameInfo(hMP3Decoder, &mp3FrameInfo);
}
} while (!outOfData);
// printstr("FINISHED: ");
// printintln(err);
MP3FreeDecoder(hMP3Decoder);
// printDebug(1, debugChan);
return 0;
}
void shutdown_mp3() {
MP3FreeDecoder(hMP3Decoder);
}
int main(int argc, char **argv)
{
int bytesLeft, nRead, err, offset, outOfData, eofReached;
unsigned char readBuf[READBUF_SIZE], *readPtr;
short outBuf[MAX_NCHAN * MAX_NGRAN * MAX_NSAMP];
FILE *infile, *outfile;
MP3FrameInfo mp3FrameInfo;
HMP3Decoder hMP3Decoder;
int startTime, endTime, diffTime, totalDecTime, nFrames;
#ifdef ARM_ADS
float audioSecs;
#endif
if (argc != 3) {
printf("usage: mp3dec infile.mp3 outfile.pcm\n");
return -1;
}
infile = fopen(argv[1], "rb");
if (!infile) {
printf("file open error\n");
return -1;
}
if (strcmp(argv[2], "nul")) {
outfile = fopen(argv[2], "wb");
if (!outfile) {
printf("file open error\n");
return -1;
}
} else {
outfile = 0; /* nul output */
}
DebugMemCheckInit();
InitTimer();
DebugMemCheckStartPoint();
if ( (hMP3Decoder = MP3InitDecoder()) == 0 )
return -2;
DebugMemCheckEndPoint();
bytesLeft = 0;
outOfData = 0;
eofReached = 0;
readPtr = readBuf;
nRead = 0;
totalDecTime = 0;
nFrames = 0;
do {
/* somewhat arbitrary trigger to refill buffer - should always be enough for a full frame */
if (bytesLeft < 2*MAINBUF_SIZE && !eofReached) {
nRead = FillReadBuffer(readBuf, readPtr, READBUF_SIZE, bytesLeft, infile);
bytesLeft += nRead;
readPtr = readBuf;
if (nRead == 0)
eofReached = 1;
}
/* find start of next MP3 frame - assume EOF if no sync found */
offset = MP3FindSyncWord(readPtr, bytesLeft);
if (offset < 0) {
outOfData = 1;
break;
}
readPtr += offset;
bytesLeft -= offset;
/* decode one MP3 frame - if offset < 0 then bytesLeft was less than a full frame */
startTime = ReadTimer();
err = MP3Decode(hMP3Decoder, &readPtr, &bytesLeft, outBuf, 0);
nFrames++;
endTime = ReadTimer();
diffTime = CalcTimeDifference(startTime, endTime);
totalDecTime += diffTime;
#if defined ARM_ADS && defined MAX_ARM_FRAMES
printf("frame %5d start = %10d, end = %10d elapsed = %10d ticks\r",
nFrames, startTime, endTime, diffTime);
fflush(stdout);
#endif
if (err) {
/* error occurred */
switch (err) {
case ERR_MP3_INDATA_UNDERFLOW:
outOfData = 1;
break;
case ERR_MP3_MAINDATA_UNDERFLOW:
/* do nothing - next call to decode will provide more mainData */
break;
case ERR_MP3_FREE_BITRATE_SYNC:
default:
outOfData = 1;
break;
}
} else {
/* no error */
MP3GetLastFrameInfo(hMP3Decoder, &mp3FrameInfo);
if (outfile)
fwrite(outBuf, mp3FrameInfo.bitsPerSample / 8, mp3FrameInfo.outputSamps, outfile);
}
#if defined ARM_ADS && defined MAX_ARM_FRAMES
if (nFrames >= MAX_ARM_FRAMES)
break;
#endif
} while (!outOfData);
#ifdef ARM_ADS
MP3GetLastFrameInfo(hMP3Decoder, &mp3FrameInfo);
audioSecs = ((float)nFrames * mp3FrameInfo.outputSamps) / ( (float)mp3FrameInfo.samprate * mp3FrameInfo.nChans);
printf("\nTotal clock ticks = %d, MHz usage = %.2f\n", totalDecTime, ARMULATE_MUL_FACT * (1.0f / audioSecs) * totalDecTime * GetClockDivFactor() / 1e6f);
printf("nFrames = %d, output samps = %d, sampRate = %d, nChans = %d\n", nFrames, mp3FrameInfo.outputSamps, mp3FrameInfo.samprate, mp3FrameInfo.nChans);
#endif
MP3FreeDecoder(hMP3Decoder);
fclose(infile);
if (outfile)
fclose(outfile);
FreeTimer();
DebugMemCheckFree();
return 0;
}
/**
* @brief mp3_player 进行mp3文件解码、播放
* @param filename:要播放的文件路径
* @retval none
*/
static void mp3_player(const char *filename)
{
int err, i, outputSamps, current_sample_rate = 0;
int read_offset = 0; /* 读偏移指针 */
int bytes_left = 0; /* 剩余字节数 */
unsigned long Frames = 0; /* mP3帧计数 */
unsigned char *read_ptr = buffer; /* 缓冲区指针 */
HMP3Decoder Mp3Decoder; /* mp3解码器指针 */
//打开音频文件
fres = f_open (&file, filename, FA_READ );
//打开失败
if (fres!=FR_OK)
{
printf("read file %s error ! open another file\r\n",filename);
fres = f_close (&file);
if (++play_index>=file_num) //索引值加1
{
play_index=0; //归0，所以如果所有文件都打开失败会一直循环
}
return ; //文件无法打开，终止解码。进入下一次循环，读取下一个文件
}
//打开成功
//初始化MP3解码器
Mp3Decoder = MP3InitDecoder();
//获取输入数据流，调用helix库解码，输出PCM数据，约20ms完成一次循环
//开始进入播放状态,期间中断会修改touch_even状态
while(player_state != S_SWITCH) //循环1， 如果touch_even不是切歌状态则继续呆在循环体里
{
//有时出现解码错误，错误后继续在本循环体内，继续播放
//显示播放图标
Lcd_GramScan(1);
LCD_Clear(12,88,8,145,BACKGROUND);
Lcd_show_bmp(320-(103+((play_index-((current_page-1)*8))*18)),240-20,"/mp3player/ui_playing.bmp");
//读取mp3文件
fres = f_read(&file, buffer, sizeof(buffer), &rw_num);
if(fres != FR_OK)
{
printf("读取%s失败！ %d\r\n",filename,fres);
break;
//return;
}
read_ptr = buffer; //指向mp3输入流
bytes_left = rw_num; //实际读到的输入流大小大小
//按帧处理
while(player_state != S_SWITCH) //循环2，循环本过程播放音频，直到按了下一首、上一首
{
if (player_state == S_STOP)
{
even_process(); //检查是否有事件需要处理
continue; //暂停的时候结束本次循环
}
player_state = S_PLAY; //状态更新为正在播放
read_offset = MP3FindSyncWord(read_ptr, bytes_left); //寻找帧同步，返回第一个同步字的位置
if(read_offset < 0) //没有找到同步字
{
break; //跳出循环2，回到循环1
}
read_ptr += read_offset; //偏移至同步字的位置
bytes_left -= read_offset; //同步字之后的数据大小
if(bytes_left < 1024) //补充数据
{
/* 注意这个地方因为采用的是DMA读取，所以一定要4字节对齐 */
i=(uint32_t)(bytes_left)&3; //判断多余的字节
if(i) i=4-i; //需要补充的字节
memcpy(buffer+i, read_ptr, bytes_left); //从对齐位置开始复制
read_ptr = buffer+i; //指向数据对齐位置
fres = f_read(&file, buffer+bytes_left+i, sizeof(buffer)-bytes_left-i, &rw_num);//补充数据
bytes_left += rw_num; //有效数据流大小
}
err = MP3Decode(Mp3Decoder, &read_ptr, &bytes_left, outBuf[bufflag], 0); //开始解码 参数：mp3解码结构体、输入流指针、输入流大小、输出流指针、数据格式
Frames++;
if (err != ERR_MP3_NONE) //错误处理
{
switch (err)
{
case ERR_MP3_INDATA_UNDERFLOW:
printf("ERR_MP3_INDATA_UNDERFLOW\r\n");
read_ptr = buffer;
fres = f_read(&file, read_ptr, sizeof(buffer), &rw_num);
bytes_left = rw_num;
break;
case ERR_MP3_MAINDATA_UNDERFLOW:
/* do nothing - next call to decode will provide more mainData */
printf("ERR_MP3_MAINDATA_UNDERFLOW\r\n");
break;
default:
printf("UNKNOWN ERROR:%d\r\n", err);
// 跳过此帧
if (bytes_left > 0)
{
bytes_left --;
read_ptr ++;
}
break;
}
}
else //解码无错误，准备把数据输出到PCM
{
MP3GetLastFrameInfo(Mp3Decoder, &Mp3FrameInfo); //获取解码信息
/* 根据解码信息设置采样率 */
if (Mp3FrameInfo.samprate != current_sample_rate) //采样率
{
current_sample_rate = Mp3FrameInfo.samprate;
printf(" \r\n Bitrate %dKbps", Mp3FrameInfo.bitrate/1000);
printf(" \r\n Samprate %dHz", current_sample_rate);
printf(" \r\n BitsPerSample %db", Mp3FrameInfo.bitsPerSample);
printf(" \r\n nChans %d", Mp3FrameInfo.nChans);
printf(" \r\n Layer %d", Mp3FrameInfo.layer);
printf(" \r\n Version %d", Mp3FrameInfo.version);
printf(" \r\n OutputSamps %d", Mp3FrameInfo.outputSamps);
if(current_sample_rate >= I2S_AudioFreq_Default) //I2S_AudioFreq_Default = 2，正常的帧，每次都要改速率
{
I2S_Freq_Config(current_sample_rate); //根据采样率修改iis速率
}
}
/* 输出到DAC */
outputSamps = Mp3FrameInfo.outputSamps; //PCM数据个数
if (outputSamps > 0)
{
if (Mp3FrameInfo.nChans == 1) //单声道
{
//单声道数据需要复制一份到另一个声道
for (i = outputSamps - 1; i >= 0; i--)
{
outBuf[bufflag][i * 2] = outBuf[bufflag][i];
outBuf[bufflag][i * 2 + 1] = outBuf[bufflag][i];
}
outputSamps *= 2;
}
//非单声道数据可直接由DMA传输到IIS交给DAC
/* 等待DMA播放完，这段时间我们可以干其他的事，扫描事件进行处理 */
while((DMA1_Channel5->CCR&DMA_CCR1_EN) && !(DMA1->ISR&DMA1_IT_TC5))
{
even_process();
}
/*DMA传输完毕*/
DMA_ClearFlag(DMA1_FLAG_TC5 | DMA1_FLAG_TE5);
DMA_I2S_Configuration((uint32_t)outBuf[bufflag], outputSamps);
bufflag = 1 -bufflag; //切换buffer
}//if (outputSamps > 0)
}//else 解码正常
if(file.fptr==file.fsize) //如果指针指向了文件尾，表示数据全部读完
{
printf("END\r\n");
if(play_index<file_num-1) //自动开始下一首歌曲
{
play_index++;
player_state = S_SWITCH; //进入切歌状态，跳出
}
else
{
play_index = 0;
player_state = S_SWITCH;
}
break; //跳出这首歌的播放状态 while break;
}
}//循环2 内 while(player_state != S_SWITCH)
}//循环1 外 while(player_state != S_SWITCH)
f_close(&file); //结束播放本歌曲，关闭文件
MP3FreeDecoder(Mp3Decoder);
I2S_Stop();
}
