123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134 |
- #include <stdio.h>
- #include <string.h>
- #include "../../Pico/sound/mix.h"
- #include "code940/940shared.h"
- #include "helix/pub/mp3dec.h"
- static short mp3_out_buffer[2*1152];
- static HMP3Decoder mp3dec = 0;
- static int mp3_buffer_offs = 0;
- extern _940_ctl_t *shared_ctl;
- extern unsigned char *mp3_mem;
- extern int PsndRate;
- static int try_get_header(unsigned char *buff, MP3FrameInfo *fi)
- {
- int ret, offs1, offs = 0;
- while (1)
- {
- offs1 = MP3FindSyncWord(buff + offs, 2048 - offs);
- if (offs1 < 0) return -2;
- offs += offs1;
- if (2048 - offs < 4) return -3;
- // printf("trying header %08x\n", *(int *)(buff + offs));
- ret = MP3GetNextFrameInfo(mp3dec, fi, buff + offs);
- if (ret == 0 && fi->bitrate != 0) break;
- offs++;
- }
- return ret;
- }
- int mp3_get_bitrate(FILE *f, int len)
- {
- unsigned char buff[2048];
- MP3FrameInfo fi;
- int ret;
- memset(buff, 0, 2048);
- if (!mp3dec) mp3dec = MP3InitDecoder();
- fseek(f, 0, SEEK_SET);
- ret = fread(buff, 1, 2048, f);
- fseek(f, 0, SEEK_SET);
- if (ret <= 0) return -1;
- ret = try_get_header(buff, &fi);
- if (ret != 0 || fi.bitrate == 0) {
- // try to read somewhere around the middle
- fseek(f, len>>1, SEEK_SET);
- fread(buff, 1, 2048, f);
- fseek(f, 0, SEEK_SET);
- ret = try_get_header(buff, &fi);
- }
- if (ret != 0) return ret;
- // printf("bitrate: %i\n", fi.bitrate / 1000);
- return fi.bitrate / 1000;
- }
- static void mp3_decode(void)
- {
- // tried copying this to cached mem, no improvement noticed
- int mp3_offs = shared_ctl->mp3_offs;
- unsigned char *readPtr = mp3_mem + mp3_offs;
- int bytesLeft = shared_ctl->mp3_len - mp3_offs;
- int offset; // frame offset from readPtr
- int err;
- if (bytesLeft <= 0) return; // EOF, nothing to do
- offset = MP3FindSyncWord(readPtr, bytesLeft);
- if (offset < 0) {
- shared_ctl->mp3_offs = shared_ctl->mp3_len;
- return; // EOF
- }
- readPtr += offset;
- bytesLeft -= offset;
- err = MP3Decode(mp3dec, &readPtr, &bytesLeft, mp3_out_buffer, 0);
- if (err) {
- if (err == ERR_MP3_INDATA_UNDERFLOW) {
- shared_ctl->mp3_offs = shared_ctl->mp3_len; // EOF
- return;
- } else if (err <= -6 && err >= -12) {
- // ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_*
- // just try to skip the offending frame..
- readPtr++;
- }
- shared_ctl->mp3_errors++;
- shared_ctl->mp3_lasterr = err;
- }
- shared_ctl->mp3_offs = readPtr - mp3_mem;
- }
- void mp3_update_local(int *buffer, int length, int stereo)
- {
- int length_mp3, shr = 0;
- void (*mix_samples)(int *dest_buf, short *mp3_buf, int count) = mix_16h_to_32;
- length_mp3 = length;
- if (PsndRate == 22050) { mix_samples = mix_16h_to_32_s1; length_mp3 <<= 1; shr = 1; }
- else if (PsndRate == 11025) { mix_samples = mix_16h_to_32_s2; length_mp3 <<= 2; shr = 2; }
- if (1152 - mp3_buffer_offs >= length_mp3) {
- mix_samples(buffer, mp3_out_buffer + mp3_buffer_offs*2, length<<1);
- mp3_buffer_offs += length_mp3;
- } else {
- int left = 1152 - mp3_buffer_offs;
- mix_samples(buffer, mp3_out_buffer + mp3_buffer_offs*2, (left>>shr)<<1);
- mp3_decode();
- mp3_buffer_offs = length_mp3 - left;
- mix_samples(buffer + ((left>>shr)<<1), mp3_out_buffer, (mp3_buffer_offs>>shr)<<1);
- }
- }
- void mp3_start_local(void)
- {
- mp3_buffer_offs = 0;
- mp3_decode();
- }
|