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1 | /* |
2 | * Some mp3 related code for Sega/Mega CD. |
3 | * Uses Libav/FFmpeg libavcodec |
4 | * (C) notaz, 2013 |
5 | * |
6 | * This work is licensed under the terms of MAME license. |
7 | * See COPYING file in the top-level directory. |
8 | */ |
9 | |
10 | #include <stdio.h> |
11 | #include <string.h> |
12 | #include <libavcodec/avcodec.h> |
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13 | #include <dlfcn.h> |
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14 | |
15 | #include <pico/pico_int.h> |
16 | #include "../libpicofe/lprintf.h" |
17 | #include "mp3.h" |
18 | |
19 | static AVCodecContext *ctx; |
20 | |
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21 | /* avoid compile time linking to libavcodec due to huge list of it's deps.. |
22 | * we also use this old API as newer one is not available on pandora */ |
23 | void (*p_av_init_packet)(AVPacket *pkt); |
24 | int (*p_avcodec_decode_audio3)(AVCodecContext *avctx, int16_t *samples, |
25 | int *frame_size_ptr, AVPacket *avpkt); |
26 | |
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27 | int mp3dec_decode(FILE *f, int *file_pos, int file_len) |
28 | { |
29 | unsigned char input_buf[2 * 1024]; |
30 | int frame_size; |
31 | AVPacket avpkt; |
32 | int bytes_in; |
33 | int bytes_out; |
34 | int offset; |
35 | int len; |
36 | |
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37 | p_av_init_packet(&avpkt); |
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38 | |
39 | do |
40 | { |
41 | if (*file_pos >= file_len) |
42 | return 1; // EOF, nothing to do |
43 | |
44 | fseek(f, *file_pos, SEEK_SET); |
45 | bytes_in = fread(input_buf, 1, sizeof(input_buf), f); |
46 | |
47 | offset = mp3_find_sync_word(input_buf, bytes_in); |
48 | if (offset < 0) { |
49 | lprintf("find_sync_word (%i/%i) err %i\n", |
50 | *file_pos, file_len, offset); |
51 | *file_pos = file_len; |
52 | return 1; // EOF |
53 | } |
54 | |
55 | // to avoid being flooded with "incorrect frame size" errors, |
56 | // we must calculate and pass exact frame size - lame |
57 | frame_size = mpeg1_l3_bitrates[input_buf[offset + 2] >> 4]; |
58 | frame_size = frame_size * 144000 / 44100; |
59 | frame_size += (input_buf[offset + 2] >> 1) & 1; |
60 | |
61 | if (offset > 0 && bytes_in - offset < frame_size) { |
62 | // underflow |
63 | *file_pos += offset; |
64 | continue; |
65 | } |
66 | |
67 | avpkt.data = input_buf + offset; |
68 | avpkt.size = frame_size; |
69 | bytes_out = sizeof(cdda_out_buffer); |
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70 | #if LIBAVCODEC_VERSION_MAJOR < 53 |
71 | // stupidity in v52: enforces this size even when |
72 | // it doesn't need/use that much at all |
73 | bytes_out = AVCODEC_MAX_AUDIO_FRAME_SIZE; |
74 | #endif |
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75 | |
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76 | len = p_avcodec_decode_audio3(ctx, cdda_out_buffer, |
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77 | &bytes_out, &avpkt); |
78 | if (len <= 0) { |
79 | lprintf("mp3 decode err (%i/%i) %i\n", |
80 | *file_pos, file_len, len); |
81 | |
82 | // attempt to skip the offending frame.. |
83 | *file_pos += offset + 1; |
84 | continue; |
85 | } |
86 | |
87 | *file_pos += offset + len; |
88 | } |
89 | while (0); |
90 | |
91 | return 0; |
92 | } |
93 | |
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94 | int mp3dec_start(FILE *f, int fpos_start) |
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95 | { |
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96 | void (*avcodec_register_all)(void); |
97 | AVCodec *(*avcodec_find_decoder)(enum CodecID id); |
98 | AVCodecContext *(*avcodec_alloc_context)(void); |
99 | int (*avcodec_open)(AVCodecContext *avctx, AVCodec *codec); |
100 | void (*av_free)(void *ptr); |
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101 | AVCodec *codec; |
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102 | void *soh; |
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103 | int ret; |
104 | |
105 | if (ctx != NULL) |
106 | return 0; |
107 | |
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108 | // either v52 or v53 should be ok |
109 | soh = dlopen("libavcodec.so.52", RTLD_NOW); |
110 | if (soh == NULL) |
111 | soh = dlopen("libavcodec.so.53", RTLD_NOW); |
112 | if (soh == NULL) { |
113 | lprintf("mp3dec: load libavcodec.so: %s\n", dlerror()); |
114 | return -1; |
115 | } |
116 | |
117 | avcodec_register_all = dlsym(soh, "avcodec_register_all"); |
118 | avcodec_find_decoder = dlsym(soh, "avcodec_find_decoder"); |
119 | avcodec_alloc_context = dlsym(soh, "avcodec_alloc_context"); |
120 | avcodec_open = dlsym(soh, "avcodec_open"); |
121 | av_free = dlsym(soh, "av_free"); |
122 | p_av_init_packet = dlsym(soh, "av_init_packet"); |
123 | p_avcodec_decode_audio3 = dlsym(soh, "avcodec_decode_audio3"); |
124 | |
125 | if (avcodec_register_all == NULL || avcodec_find_decoder == NULL |
126 | || avcodec_alloc_context == NULL || avcodec_open == NULL |
127 | || av_free == NULL |
128 | || p_av_init_packet == NULL || p_avcodec_decode_audio3 == NULL) |
129 | { |
130 | lprintf("mp3dec: missing symbol(s) in libavcodec.so\n"); |
131 | dlclose(soh); |
132 | return -1; |
133 | } |
134 | |
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135 | // init decoder |
136 | |
137 | //avcodec_init(); |
138 | avcodec_register_all(); |
139 | |
140 | // AV_CODEC_ID_MP3 ? |
141 | codec = avcodec_find_decoder(CODEC_ID_MP3); |
142 | if (codec == NULL) { |
143 | lprintf("mp3dec: codec missing\n"); |
144 | return -1; |
145 | } |
146 | |
147 | ctx = avcodec_alloc_context(); |
148 | if (ctx == NULL) { |
149 | lprintf("mp3dec: avcodec_alloc_context failed\n"); |
150 | return -1; |
151 | } |
152 | |
153 | ret = avcodec_open(ctx, codec); |
154 | if (ret < 0) { |
155 | lprintf("mp3dec: avcodec_open failed: %d\n", ret); |
156 | av_free(ctx); |
157 | ctx = NULL; |
158 | return -1; |
159 | } |
160 | |
161 | return 0; |
162 | } |