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[picodrive.git] / platform / common / mp3_helix.c
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1// Some mp3 related code for Sega/Mega CD.
2// Uses the Helix Fixed-point MP3 decoder
3
4// (c) Copyright 2007, Grazvydas "notaz" Ignotas
5
6#include <stdio.h>
7#include <string.h>
8
9#include "../../Pico/PicoInt.h"
10#include "../../Pico/sound/mix.h"
11#include "helix/pub/mp3dec.h"
12#include "lprintf.h"
13
14static HMP3Decoder mp3dec = 0;
15static int mp3_buffer_offs = 0;
16
17
18static int find_sync_word(unsigned char *buf, int nBytes)
19{
20 unsigned char *p, *pe;
21
22 /* find byte-aligned syncword - need 12 (MPEG 1,2) or 11 (MPEG 2.5) matching bits */
23 for (p = buf, pe = buf + nBytes - 4; p < pe; p++)
24 {
25 int pn;
26 if (p[0] != 0xff) continue;
27 pn = p[1];
28 if ((pn & 0xf8) != 0xf8 || // currently must be MPEG1
29 (pn & 6) == 0) { // invalid layer
30 p++; continue;
31 }
32 pn = p[2];
33 if ((pn & 0xf0) < 0x20 || (pn & 0xf0) == 0xf0 || // bitrates
34 (pn & 0x0c) != 0) { // not 44kHz
35 continue;
36 }
37
38 return p - buf;
39 }
40
41 return -1;
42}
43
44
45static int try_get_header(unsigned char *buff, MP3FrameInfo *fi)
46{
47 int ret, offs1, offs = 0;
48
49 while (1)
50 {
51 offs1 = find_sync_word(buff + offs, 2048 - offs);
52 if (offs1 < 0) return -2;
53 offs += offs1;
54 if (2048 - offs < 4) return -3;
55
56 // printf("trying header %08x\n", *(int *)(buff + offs));
57
58 ret = MP3GetNextFrameInfo(mp3dec, fi, buff + offs);
59 if (ret == 0 && fi->bitrate != 0) break;
60 offs++;
61 }
62
63 return ret;
64}
65
66int mp3_get_bitrate(FILE *f, int len)
67{
68 unsigned char buff[2048];
69 MP3FrameInfo fi;
70 int ret;
71
72 memset(buff, 0, 2048);
73
74 if (mp3dec) MP3FreeDecoder(mp3dec);
75 mp3dec = MP3InitDecoder();
76
77 fseek(f, 0, SEEK_SET);
78 ret = fread(buff, 1, 2048, f);
79 fseek(f, 0, SEEK_SET);
80 if (ret <= 0) return -1;
81
82 ret = try_get_header(buff, &fi);
83 if (ret != 0 || fi.bitrate == 0) {
84 // try to read somewhere around the middle
85 fseek(f, len>>1, SEEK_SET);
86 fread(buff, 1, 2048, f);
87 fseek(f, 0, SEEK_SET);
88 ret = try_get_header(buff, &fi);
89 }
90 if (ret != 0) return ret;
91
92 // printf("bitrate: %i\n", fi.bitrate / 1000);
93
94 return fi.bitrate / 1000;
95}
96
97
98#ifdef __GP2X__
99
100#include "../gp2x/code940/940shared.h"
101
102extern _940_ctl_t *shared_ctl;
103extern unsigned char *mp3_mem;
104
105static int mp3_decode(void)
106{
107 // tried copying this to cached mem, no improvement noticed
108 int mp3_offs = shared_ctl->mp3_offs;
109 unsigned char *readPtr = mp3_mem + mp3_offs;
110 int bytesLeft = shared_ctl->mp3_len - mp3_offs;
111 int offset; // frame offset from readPtr
112 int retries = 0, err;
113
114 if (bytesLeft <= 0) return 1; // EOF, nothing to do
115
116retry:
117 offset = find_sync_word(readPtr, bytesLeft);
118 if (offset < 0) {
119 shared_ctl->mp3_offs = shared_ctl->mp3_len;
120 return 1; // EOF
121 }
122 readPtr += offset;
123 bytesLeft -= offset;
124
125 err = MP3Decode(mp3dec, &readPtr, &bytesLeft, cdda_out_buffer, 0);
126 if (err) {
127 if (err == ERR_MP3_INDATA_UNDERFLOW) {
128 shared_ctl->mp3_offs = shared_ctl->mp3_len; // EOF
129 return 1;
130 } else if (err <= -6 && err >= -12) {
131 // ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_*
132 // just try to skip the offending frame..
133 readPtr++;
134 bytesLeft--;
135 if (retries++ < 2) goto retry;
136 else lprintf("mp3 decode failed with %i after %i retries\n", err, retries);
137 }
138 shared_ctl->mp3_errors++;
139 shared_ctl->mp3_lasterr = err;
140 }
141 shared_ctl->mp3_offs = readPtr - mp3_mem;
142 return 0;
143}
144
145void mp3_start_local(void)
146{
147 // must re-init decoder for new track
148 if (mp3dec) MP3FreeDecoder(mp3dec);
149 mp3dec = MP3InitDecoder();
150
151 mp3_buffer_offs = 0;
152 mp3_decode();
153}
154
155#define mp3_update mp3_update_local
156
157#else // !__GP2X__
158
159static FILE *mp3_current_file = NULL;
160static int mp3_file_len = 0, mp3_file_pos = 0;
161static unsigned char mp3_input_buffer[2*1024];
162
163static int mp3_decode(void)
164{
165 unsigned char *readPtr;
166 int bytesLeft;
167 int offset; // mp3 frame offset from readPtr
168 int err;
169
170 do
171 {
172 if (mp3_file_pos >= mp3_file_len) return 1; // EOF, nothing to do
173
174 fseek(mp3_current_file, mp3_file_pos, SEEK_SET);
175 bytesLeft = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), mp3_current_file);
176
177 offset = find_sync_word(mp3_input_buffer, bytesLeft);
178 if (offset < 0) {
179 //lprintf("find_sync_word (%i/%i) err %i\n", mp3_file_pos, mp3_file_len, offset);
180 mp3_file_pos = mp3_file_len;
181 return 1; // EOF
182 }
183 readPtr = mp3_input_buffer + offset;
184 bytesLeft -= offset;
185
186 err = MP3Decode(mp3dec, &readPtr, &bytesLeft, cdda_out_buffer, 0);
187 if (err) {
188 //lprintf("MP3Decode err (%i/%i) %i\n", mp3_file_pos, mp3_file_len, err);
189 if (err == ERR_MP3_INDATA_UNDERFLOW) {
190 if (offset == 0)
191 // something's really wrong here, frame had to fit
192 mp3_file_pos = mp3_file_len;
193 else
194 mp3_file_pos += offset;
195 continue;
196 } else if (err <= -6 && err >= -12) {
197 // ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_*
198 // just try to skip the offending frame..
199 mp3_file_pos += offset + 1;
200 continue;
201 }
202 mp3_file_pos = mp3_file_len;
203 return 1;
204 }
205 mp3_file_pos += readPtr - mp3_input_buffer;
206 }
207 while (0);
208
209 return 0;
210}
211
212void mp3_start_play(FILE *f, int pos)
213{
214 mp3_file_len = mp3_file_pos = 0;
215 mp3_current_file = NULL;
216 mp3_buffer_offs = 0;
217
218 // must re-init decoder for new track
219 if (mp3dec) MP3FreeDecoder(mp3dec);
220 mp3dec = MP3InitDecoder();
221
222 if (!(PicoOpt&POPT_EN_MCD_CDDA) || f == NULL) // cdda disabled or no file?
223 return;
224
225 //lprintf("mp3_start_play %p %i\n", f, pos);
226
227 mp3_current_file = f;
228 fseek(f, 0, SEEK_END);
229 mp3_file_len = ftell(f);
230
231 // seek..
232 if (pos) {
233 mp3_file_pos = (mp3_file_len << 6) >> 10;
234 mp3_file_pos *= pos;
235 mp3_file_pos >>= 6;
236 }
237
238 mp3_decode();
239}
240
241int mp3_get_offset(void)
242{
243 unsigned int offs1024 = 0;
244 int cdda_on;
245
246 cdda_on = (PicoAHW & PAHW_MCD) && (PicoOpt&POPT_EN_MCD_CDDA) && !(Pico_mcd->s68k_regs[0x36] & 1) &&
247 (Pico_mcd->scd.Status_CDC & 1) && mp3_current_file != NULL;
248
249 if (cdda_on) {
250 offs1024 = mp3_file_pos << 7;
251 offs1024 /= mp3_file_len >> 3;
252 }
253 //lprintf("mp3_get_offset offs1024=%u (%i/%i)\n", offs1024, mp3_file_pos, mp3_file_len);
254
255 return offs1024;
256}
257
258#endif // ifndef __GP2X__
259
260void mp3_update(int *buffer, int length, int stereo)
261{
262 int length_mp3, shr = 0;
263 void (*mix_samples)(int *dest_buf, short *mp3_buf, int count) = mix_16h_to_32;
264
265#ifndef __GP2X__
266 if (mp3_current_file == NULL || mp3_file_pos >= mp3_file_len) return; // no file / EOF
267#endif
268
269 length_mp3 = length;
270 if (PsndRate == 22050) { mix_samples = mix_16h_to_32_s1; length_mp3 <<= 1; shr = 1; }
271 else if (PsndRate == 11025) { mix_samples = mix_16h_to_32_s2; length_mp3 <<= 2; shr = 2; }
272
273 if (1152 - mp3_buffer_offs >= length_mp3) {
274 mix_samples(buffer, cdda_out_buffer + mp3_buffer_offs*2, length<<1);
275
276 mp3_buffer_offs += length_mp3;
277 } else {
278 int ret, left = 1152 - mp3_buffer_offs;
279
280 mix_samples(buffer, cdda_out_buffer + mp3_buffer_offs*2, (left>>shr)<<1);
281 ret = mp3_decode();
282 if (ret == 0) {
283 mp3_buffer_offs = length_mp3 - left;
284 mix_samples(buffer + ((left>>shr)<<1), cdda_out_buffer, (mp3_buffer_offs>>shr)<<1);
285 } else
286 mp3_buffer_offs = 0;
287 }
288}
289
290