diff options
Diffstat (limited to 'lib/rbcodec/codecs/libgme/resampler.c')
-rw-r--r-- | lib/rbcodec/codecs/libgme/resampler.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libgme/resampler.c b/lib/rbcodec/codecs/libgme/resampler.c new file mode 100644 index 0000000000..c4f42a9794 --- /dev/null +++ b/lib/rbcodec/codecs/libgme/resampler.c | |||
@@ -0,0 +1,218 @@ | |||
1 | // Game_Music_Emu 0.5.5. http://www.slack.net/~ant/ | ||
2 | |||
3 | #include "resampler.h" | ||
4 | |||
5 | #include <stdlib.h> | ||
6 | #include <string.h> | ||
7 | |||
8 | /* Copyright (C) 2003-2006 Shay Green. This module is free software; you | ||
9 | can redistribute it and/or modify it under the terms of the GNU Lesser | ||
10 | General Public License as published by the Free Software Foundation; either | ||
11 | version 2.1 of the License, or (at your option) any later version. This | ||
12 | module is distributed in the hope that it will be useful, but WITHOUT ANY | ||
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | ||
14 | FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more | ||
15 | details. You should have received a copy of the GNU Lesser General Public | ||
16 | License along with this module; if not, write to the Free Software Foundation, | ||
17 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ | ||
18 | |||
19 | #include "blargg_source.h" | ||
20 | |||
21 | // TODO: fix this. hack since resampler holds back some output. | ||
22 | unsigned const resampler_extra = 34; | ||
23 | |||
24 | enum { shift = 14 }; | ||
25 | int const unit = 1 << shift; | ||
26 | |||
27 | blargg_err_t Resampler_setup( struct Resampler* this, int fm_rate, int fm_gain, int rate, int gain ) | ||
28 | { | ||
29 | this->gain_ = (int)( ((1LL << gain_bits) * fm_gain * gain) / FP_ONE_GAIN ); | ||
30 | this->step = (int)( ((1LL << shift) * fm_rate) / rate + 1); | ||
31 | this->rate_ = this->step; | ||
32 | return 0; | ||
33 | } | ||
34 | |||
35 | blargg_err_t Resampler_reset( struct Resampler* this, int pairs ) | ||
36 | { | ||
37 | // expand allocations a bit | ||
38 | this->sample_buffer_size = (pairs + (pairs >> 2)) * 2; | ||
39 | Resampler_resize( this, pairs ); | ||
40 | this->resampler_size = this->oversamples_per_frame + (this->oversamples_per_frame >> 2); | ||
41 | |||
42 | this->buffer_size = this->resampler_size; | ||
43 | this->pos = 0; | ||
44 | this->write_pos = 0; | ||
45 | |||
46 | Resampler_clear( this ); | ||
47 | return 0; | ||
48 | } | ||
49 | |||
50 | void Resampler_resize( struct Resampler* this, int pairs ) | ||
51 | { | ||
52 | int new_sample_buf_size = pairs * 2; | ||
53 | if ( this->sample_buf_size != new_sample_buf_size ) | ||
54 | { | ||
55 | if ( new_sample_buf_size > this->sample_buffer_size ) | ||
56 | { | ||
57 | check(false); | ||
58 | return; | ||
59 | } | ||
60 | |||
61 | this->sample_buf_size = new_sample_buf_size; | ||
62 | this->oversamples_per_frame = (int) ((pairs * this->rate_ * 2LL) / unit) + 2; | ||
63 | Resampler_clear( this ); | ||
64 | } | ||
65 | } | ||
66 | |||
67 | static void mix_samples( struct Resampler* this, struct Blip_Buffer* blip_buf, dsample_t out_ [] ) | ||
68 | { | ||
69 | int const bass = BLIP_READER_BASS( *blip_buf ); | ||
70 | BLIP_READER_BEGIN( sn, *blip_buf ); | ||
71 | |||
72 | int count = this->sample_buf_size >> 1; | ||
73 | BLIP_READER_ADJ_( sn, count ); | ||
74 | |||
75 | typedef dsample_t stereo_dsample_t [2]; | ||
76 | stereo_dsample_t* BLARGG_RESTRICT out = (stereo_dsample_t*) out_ + count; | ||
77 | stereo_dsample_t const* BLARGG_RESTRICT in = | ||
78 | (stereo_dsample_t const*) this->sample_buf + count; | ||
79 | int offset = -count; | ||
80 | int const gain = this->gain_; | ||
81 | do | ||
82 | { | ||
83 | int s = BLIP_READER_READ_RAW( sn ) >> (blip_sample_bits - 16); | ||
84 | BLIP_READER_NEXT_IDX_( sn, bass, offset ); | ||
85 | |||
86 | int l = (in [offset] [0] * gain >> gain_bits) + s; | ||
87 | int r = (in [offset] [1] * gain >> gain_bits) + s; | ||
88 | |||
89 | BLIP_CLAMP( l, l ); | ||
90 | out [offset] [0] = (blip_sample_t) l; | ||
91 | |||
92 | BLIP_CLAMP( r, r ); | ||
93 | out [offset] [1] = (blip_sample_t) r; | ||
94 | } | ||
95 | while ( ++offset ); | ||
96 | |||
97 | BLIP_READER_END( sn, *blip_buf ); | ||
98 | } | ||
99 | |||
100 | static dsample_t const* resample_( struct Resampler* this, dsample_t** out_, | ||
101 | dsample_t const* out_end, dsample_t const in [], int in_size ) | ||
102 | { | ||
103 | in_size -= write_offset; | ||
104 | if ( in_size > 0 ) | ||
105 | { | ||
106 | dsample_t* BLARGG_RESTRICT out = *out_; | ||
107 | dsample_t const* const in_end = in + in_size; | ||
108 | |||
109 | int const step = this->step; | ||
110 | int pos = this->pos; | ||
111 | |||
112 | // TODO: IIR filter, then linear resample | ||
113 | // TODO: detect skipped sample, allowing merging of IIR and resample? | ||
114 | |||
115 | do | ||
116 | { | ||
117 | #define INTERP( i, out )\ | ||
118 | out = (in [0 + i] * (unit - pos) + ((in [2 + i] + in [4 + i] + in [6 + i]) << shift) +\ | ||
119 | in [8 + i] * pos) >> (shift + 2); | ||
120 | |||
121 | int out_0; | ||
122 | INTERP( 0, out_0 ) | ||
123 | INTERP( 1, out [0] = out_0; out [1] ) | ||
124 | out += stereo; | ||
125 | |||
126 | pos += step; | ||
127 | in += ((unsigned) pos >> shift) * stereo; | ||
128 | pos &= unit - 1; | ||
129 | } | ||
130 | while ( in < in_end && out < out_end ); | ||
131 | |||
132 | this->pos = pos; | ||
133 | *out_ = out; | ||
134 | } | ||
135 | return in; | ||
136 | } | ||
137 | |||
138 | static inline int resample_wrapper( struct Resampler* this, dsample_t out [], int* out_size, | ||
139 | dsample_t const in [], int in_size ) | ||
140 | { | ||
141 | assert( Resampler_rate( this ) ); | ||
142 | |||
143 | dsample_t* out_ = out; | ||
144 | int result = resample_( this, &out_, out + *out_size, in, in_size ) - in; | ||
145 | assert( out_ <= out + *out_size ); | ||
146 | assert( result <= in_size ); | ||
147 | |||
148 | *out_size = out_ - out; | ||
149 | return result; | ||
150 | } | ||
151 | |||
152 | static int skip_input( struct Resampler* this, int count ) | ||
153 | { | ||
154 | this->write_pos -= count; | ||
155 | if ( this->write_pos < 0 ) // occurs when downsampling | ||
156 | { | ||
157 | count += this->write_pos; | ||
158 | this->write_pos = 0; | ||
159 | } | ||
160 | memmove( this->buf, &this->buf [count], this->write_pos * sizeof this->buf [0] ); | ||
161 | return count; | ||
162 | } | ||
163 | |||
164 | static void play_frame_( struct Resampler* this, struct Blip_Buffer* blip_buf, dsample_t* out ) | ||
165 | { | ||
166 | int pair_count = this->sample_buf_size >> 1; | ||
167 | blip_time_t blip_time = Blip_count_clocks( blip_buf, pair_count ); | ||
168 | int sample_count = this->oversamples_per_frame - this->write_pos + resampler_extra; | ||
169 | |||
170 | int new_count = this->callback( this->callback_data, blip_time, sample_count, &this->buf [this->write_pos] ); | ||
171 | assert( new_count < this->resampler_size ); | ||
172 | |||
173 | Blip_end_frame( blip_buf, blip_time ); | ||
174 | assert( Blip_samples_avail( blip_buf ) == pair_count ); | ||
175 | |||
176 | this->write_pos += new_count; | ||
177 | assert( (unsigned) this->write_pos <= this->buffer_size ); | ||
178 | |||
179 | int count = this->sample_buf_size; | ||
180 | if ( count ) | ||
181 | skip_input( this, resample_wrapper( this, this->sample_buf, &count, this->buf, this->write_pos ) ); | ||
182 | assert( count == this->sample_buf_size ); | ||
183 | |||
184 | mix_samples( this, blip_buf, out ); | ||
185 | Blip_remove_samples( blip_buf, pair_count ); | ||
186 | } | ||
187 | |||
188 | void Resampler_play( struct Resampler* this, int count, dsample_t* out, struct Blip_Buffer* blip_buf ) | ||
189 | { | ||
190 | // empty extra buffer | ||
191 | int remain = this->sample_buf_size - this->buf_pos; | ||
192 | if ( remain ) | ||
193 | { | ||
194 | if ( remain > count ) | ||
195 | remain = count; | ||
196 | count -= remain; | ||
197 | memcpy( out, &this->sample_buf [this->buf_pos], remain * sizeof *out ); | ||
198 | out += remain; | ||
199 | this->buf_pos += remain; | ||
200 | } | ||
201 | |||
202 | // entire frames | ||
203 | while ( count >= this->sample_buf_size ) | ||
204 | { | ||
205 | play_frame_( this, blip_buf, out ); | ||
206 | out += this->sample_buf_size; | ||
207 | count -= this->sample_buf_size; | ||
208 | } | ||
209 | |||
210 | // extra | ||
211 | if ( count ) | ||
212 | { | ||
213 | play_frame_( this, blip_buf, this->sample_buf ); | ||
214 | this->buf_pos = count; | ||
215 | memcpy( out, this->sample_buf, count * sizeof *out ); | ||
216 | out += count; | ||
217 | } | ||
218 | } | ||