rt-thread-official/bsp/stm32_radio/mp3.c

214 lines
4.6 KiB
C

#include <rtthread.h>
#include <dfs_posix.h>
#include <mp3/pub/mp3dec.h>
#include "dac.h"
static HMP3Decoder hMP3Decoder;
static MP3FrameInfo mp3FrameInfo;
static unsigned char *read_ptr;
static int bytes_left=0, bytes_leftBeforeDecoding=0, err, offset;
static int nFrames = 0;
static unsigned char *mp3buf;
static unsigned int mp3buf_size;
static unsigned char allocated = 0;
static void mp3_reset()
{
read_ptr = RT_NULL;
bytes_leftBeforeDecoding = bytes_left = 0;
nFrames = 0;
}
void mp3_init(rt_uint8_t *buffer, rt_uint32_t buffer_size)
{
mp3buf = buffer;
mp3buf_size = buffer_size;
mp3_reset();
}
void mp3_alloc()
{
if (!allocated) hMP3Decoder = MP3InitDecoder();
allocated = 1;
}
void mp3_free()
{
if (allocated) MP3FreeDecoder(hMP3Decoder);
allocated = 0;
}
int mp3_refill_inbuffer(int fd)
{
rt_uint16_t bytes_read;
int bytes_to_read;
// rt_kprintf("left: %d. refilling inbuffer...\n", bytes_left);
if (bytes_left > 0)
{
// after fseeking backwards the FAT has to be read from the beginning -> S L O W
// assert(f_lseek(mp3file, mp3file->fptr - bytes_leftBeforeDecoding) == FR_OK);
// better: move unused rest of buffer to the start
// no overlap as long as (1024 <= mp3buf_size/2), so no need to use memove
rt_memcpy(mp3buf, read_ptr, bytes_left);
}
bytes_to_read = mp3buf_size - bytes_left;
bytes_read = read(fd, (char *)mp3buf + bytes_left, bytes_to_read);
if (bytes_read == bytes_to_read)
{
read_ptr = mp3buf;
offset = 0;
bytes_left = mp3buf_size;
// rt_kprintf("ok. read: %d. left: %d\n", bytes_read, bytes_left);
return 0;
}
else
{
rt_kprintf("can't read more data");
return -1;
}
}
int mp3_process(int fd)
{
int writeable_buffer;
if (read_ptr == RT_NULL)
{
if(mp3_refill_inbuffer(fd) != 0)
return -1;
}
offset = MP3FindSyncWord(read_ptr, bytes_left);
if (offset < 0)
{
rt_kprintf("Error: MP3FindSyncWord returned <0");
if(mp3_refill_inbuffer(fd) != 0)
return -1;
}
read_ptr += offset;
bytes_left -= offset;
bytes_leftBeforeDecoding = bytes_left;
// check if this is really a valid frame
// (the decoder does not seem to calculate CRC, so make some plausibility checks)
if (MP3GetNextFrameInfo(hMP3Decoder, &mp3FrameInfo, read_ptr) == 0 &&
mp3FrameInfo.nChans == 2 &&
mp3FrameInfo.version == 0)
{
// rt_kprintf("Found a frame at offset %x\n", offset + read_ptr - mp3buf + mp3file->fptr);
}
else
{
rt_kprintf("this is no valid frame\n");
// advance data pointer
// TODO: handle bytes_left == 0
RT_ASSERT(bytes_left > 0);
bytes_left -= 1;
read_ptr += 1;
return 0;
}
if (bytes_left < 1024) {
if(mp3_refill_inbuffer(fd) != 0)
return -1;
}
// rt_kprintf("bytes_leftBeforeDecoding: %i\n", bytes_leftBeforeDecoding);
writeable_buffer = dac_get_writeable_buffer();
if (writeable_buffer == -1) {
return 0;
}
// rt_kprintf("wb %i\n", writeable_buffer);
err = MP3Decode(hMP3Decoder, &read_ptr, &bytes_left, dac_buffer[writeable_buffer], 0);
nFrames++;
if (err)
{
switch (err)
{
case ERR_MP3_INDATA_UNDERFLOW:
rt_kprintf("ERR_MP3_INDATA_UNDERFLOW");
bytes_left = 0;
if(mp3_refill_inbuffer(fd) != 0)
return -1;
break;
case ERR_MP3_MAINDATA_UNDERFLOW:
/* do nothing - next call to decode will provide more mainData */
rt_kprintf("ERR_MP3_MAINDATA_UNDERFLOW");
break;
default:
rt_kprintf("unknown error: %i\n", err);
// skip this frame
if (bytes_left > 0)
{
bytes_left --;
read_ptr ++;
}
else
{
// TODO
RT_ASSERT(0);
}
break;
}
dac_buffer_size[writeable_buffer] = 0;
}
else
{
/* no error */
MP3GetLastFrameInfo(hMP3Decoder, &mp3FrameInfo);
// rt_kprintf("Bitrate: %i\r\n", mp3FrameInfo.bitrate);
// rt_kprintf("%i samples\n", mp3FrameInfo.outputSamps);
dac_buffer_size[writeable_buffer] = mp3FrameInfo.outputSamps;
// rt_kprintf("%lu Hz, %i kbps\n", mp3FrameInfo.samprate, mp3FrameInfo.bitrate/1000);
if (dac_set_srate(mp3FrameInfo.samprate) != 0) {
rt_kprintf("unsupported sample rate: %lu\n", mp3FrameInfo.samprate);
return -1;
}
}
return 0;
}
#include <finsh.h>
void mp3(char* filename)
{
int fd;
rt_uint8_t *mp3_buffer;
list_date();
dac_init();
mp3_buffer = rt_malloc(2048);
mp3_init(mp3_buffer, 2048);
mp3_alloc();
fd = open(filename, O_RDONLY, 0);
if (fd >= 0)
{
while (mp3_process(fd) == 0);
close(fd);
}
list_date();
}
FINSH_FUNCTION_EXPORT(mp3, mp3 decode test)