edbb82f8 |
1 | #include <stdio.h> |
2 | #include <string.h> |
3 | |
4 | #include "../../Pico/sound/mix.h" |
5 | #include "code940/940shared.h" |
6 | #include "helix/pub/mp3dec.h" |
7 | |
8 | static short mp3_out_buffer[2*1152]; |
9 | static HMP3Decoder mp3dec = 0; |
10 | static int mp3_buffer_offs = 0; |
11 | |
12 | extern _940_ctl_t *shared_ctl; |
13 | extern unsigned char *mp3_mem; |
14 | extern int PsndRate; |
15 | |
16 | |
17 | static int try_get_header(unsigned char *buff, MP3FrameInfo *fi) |
18 | { |
19 | int ret, offs1, offs = 0; |
20 | |
21 | while (1) |
22 | { |
23 | offs1 = MP3FindSyncWord(buff + offs, 2048 - offs); |
24 | if (offs1 < 0) return -2; |
25 | offs += offs1; |
26 | if (2048 - offs < 4) return -3; |
27 | |
28 | // printf("trying header %08x\n", *(int *)(buff + offs)); |
29 | |
30 | ret = MP3GetNextFrameInfo(mp3dec, fi, buff + offs); |
31 | if (ret == 0 && fi->bitrate != 0) break; |
32 | offs++; |
33 | } |
34 | |
35 | return ret; |
36 | } |
37 | |
38 | int mp3_get_bitrate(FILE *f, int len) |
39 | { |
40 | unsigned char buff[2048]; |
41 | MP3FrameInfo fi; |
42 | int ret; |
43 | |
44 | memset(buff, 0, 2048); |
45 | |
46 | if (!mp3dec) mp3dec = MP3InitDecoder(); |
47 | |
48 | fseek(f, 0, SEEK_SET); |
49 | ret = fread(buff, 1, 2048, f); |
50 | fseek(f, 0, SEEK_SET); |
51 | if (ret <= 0) return -1; |
52 | |
53 | ret = try_get_header(buff, &fi); |
54 | if (ret != 0 || fi.bitrate == 0) { |
55 | // try to read somewhere around the middle |
56 | fseek(f, len>>1, SEEK_SET); |
57 | fread(buff, 1, 2048, f); |
58 | fseek(f, 0, SEEK_SET); |
59 | ret = try_get_header(buff, &fi); |
60 | } |
61 | if (ret != 0) return ret; |
62 | |
63 | // printf("bitrate: %i\n", fi.bitrate / 1000); |
64 | |
65 | return fi.bitrate / 1000; |
66 | } |
67 | |
68 | |
69 | static void mp3_decode(void) |
70 | { |
71 | // tried copying this to cached mem, no improvement noticed |
72 | int mp3_offs = shared_ctl->mp3_offs; |
73 | unsigned char *readPtr = mp3_mem + mp3_offs; |
74 | int bytesLeft = shared_ctl->mp3_len - mp3_offs; |
75 | int offset; // frame offset from readPtr |
76 | int err; |
77 | |
78 | if (bytesLeft <= 0) return; // EOF, nothing to do |
79 | |
80 | offset = MP3FindSyncWord(readPtr, bytesLeft); |
81 | if (offset < 0) { |
82 | shared_ctl->mp3_offs = shared_ctl->mp3_len; |
83 | return; // EOF |
84 | } |
85 | readPtr += offset; |
86 | bytesLeft -= offset; |
87 | |
88 | err = MP3Decode(mp3dec, &readPtr, &bytesLeft, mp3_out_buffer, 0); |
89 | if (err) { |
90 | if (err == ERR_MP3_INDATA_UNDERFLOW) { |
91 | shared_ctl->mp3_offs = shared_ctl->mp3_len; // EOF |
92 | return; |
93 | } else if (err <= -6 && err >= -12) { |
94 | // ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_* |
95 | // just try to skip the offending frame.. |
96 | readPtr++; |
97 | } |
98 | shared_ctl->mp3_errors++; |
99 | shared_ctl->mp3_lasterr = err; |
100 | } |
101 | shared_ctl->mp3_offs = readPtr - mp3_mem; |
102 | } |
103 | |
104 | |
105 | void mp3_update_local(int *buffer, int length, int stereo) |
106 | { |
107 | int length_mp3, shr = 0; |
108 | void (*mix_samples)(int *dest_buf, short *mp3_buf, int count) = mix_16h_to_32; |
109 | |
110 | length_mp3 = length; |
111 | if (PsndRate == 22050) { mix_samples = mix_16h_to_32_s1; length_mp3 <<= 1; shr = 1; } |
112 | else if (PsndRate == 11025) { mix_samples = mix_16h_to_32_s2; length_mp3 <<= 2; shr = 2; } |
113 | |
114 | if (1152 - mp3_buffer_offs >= length_mp3) { |
115 | mix_samples(buffer, mp3_out_buffer + mp3_buffer_offs*2, length<<1); |
116 | |
117 | mp3_buffer_offs += length_mp3; |
118 | } else { |
119 | int left = 1152 - mp3_buffer_offs; |
120 | |
121 | mix_samples(buffer, mp3_out_buffer + mp3_buffer_offs*2, (left>>shr)<<1); |
122 | mp3_decode(); |
123 | mp3_buffer_offs = length_mp3 - left; |
124 | mix_samples(buffer + ((left>>shr)<<1), mp3_out_buffer, (mp3_buffer_offs>>shr)<<1); |
125 | } |
126 | } |
127 | |
128 | |
129 | void mp3_start_local(void) |
130 | { |
131 | mp3_buffer_offs = 0; |
132 | mp3_decode(); |
133 | } |
134 | |