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| 1 /* Copyright (c) 2011 Xiph.Org Foundation, Skype Limited |
| 2 Written by Jean-Marc Valin and Koen Vos */ |
| 3 /* |
| 4 Redistribution and use in source and binary forms, with or without |
| 5 modification, are permitted provided that the following conditions |
| 6 are met: |
| 7 |
| 8 - Redistributions of source code must retain the above copyright |
| 9 notice, this list of conditions and the following disclaimer. |
| 10 |
| 11 - Redistributions in binary form must reproduce the above copyright |
| 12 notice, this list of conditions and the following disclaimer in the |
| 13 documentation and/or other materials provided with the distribution. |
| 14 |
| 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 16 ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 17 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 18 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER |
| 19 OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 20 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 21 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 22 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 23 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 24 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 25 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 */ |
| 27 |
| 28 #ifdef HAVE_CONFIG_H |
| 29 #include "config.h" |
| 30 #endif |
| 31 |
| 32 #include "opus.h" |
| 33 #include "opus_private.h" |
| 34 |
| 35 #ifndef DISABLE_FLOAT_API |
| 36 OPUS_EXPORT void opus_pcm_soft_clip(float *_x, int N, int C, float *declip_mem) |
| 37 { |
| 38 int c; |
| 39 int i; |
| 40 float *x; |
| 41 |
| 42 if (C<1 || N<1 || !_x || !declip_mem) return; |
| 43 |
| 44 /* First thing: saturate everything to +/- 2 which is the highest level our |
| 45 non-linearity can handle. At the point where the signal reaches +/-2, |
| 46 the derivative will be zero anyway, so this doesn't introduce any |
| 47 discontinuity in the derivative. */ |
| 48 for (i=0;i<N*C;i++) |
| 49 _x[i] = MAX16(-2.f, MIN16(2.f, _x[i])); |
| 50 for (c=0;c<C;c++) |
| 51 { |
| 52 float a; |
| 53 float x0; |
| 54 int curr; |
| 55 |
| 56 x = _x+c; |
| 57 a = declip_mem[c]; |
| 58 /* Continue applying the non-linearity from the previous frame to avoid |
| 59 any discontinuity. */ |
| 60 for (i=0;i<N;i++) |
| 61 { |
| 62 if (x[i*C]*a>=0) |
| 63 break; |
| 64 x[i*C] = x[i*C]+a*x[i*C]*x[i*C]; |
| 65 } |
| 66 |
| 67 curr=0; |
| 68 x0 = x[0]; |
| 69 while(1) |
| 70 { |
| 71 int start, end; |
| 72 float maxval; |
| 73 int special=0; |
| 74 int peak_pos; |
| 75 for (i=curr;i<N;i++) |
| 76 { |
| 77 if (x[i*C]>1 || x[i*C]<-1) |
| 78 break; |
| 79 } |
| 80 if (i==N) |
| 81 { |
| 82 a=0; |
| 83 break; |
| 84 } |
| 85 peak_pos = i; |
| 86 start=end=i; |
| 87 maxval=ABS16(x[i*C]); |
| 88 /* Look for first zero crossing before clipping */ |
| 89 while (start>0 && x[i*C]*x[(start-1)*C]>=0) |
| 90 start--; |
| 91 /* Look for first zero crossing after clipping */ |
| 92 while (end<N && x[i*C]*x[end*C]>=0) |
| 93 { |
| 94 /* Look for other peaks until the next zero-crossing. */ |
| 95 if (ABS16(x[end*C])>maxval) |
| 96 { |
| 97 maxval = ABS16(x[end*C]); |
| 98 peak_pos = end; |
| 99 } |
| 100 end++; |
| 101 } |
| 102 /* Detect the special case where we clip before the first zero crossing
*/ |
| 103 special = (start==0 && x[i*C]*x[0]>=0); |
| 104 |
| 105 /* Compute a such that maxval + a*maxval^2 = 1 */ |
| 106 a=(maxval-1)/(maxval*maxval); |
| 107 /* Slightly boost "a" by 2^-22. This is just enough to ensure -ffast-ma
th |
| 108 does not cause output values larger than +/-1, but small enough not |
| 109 to matter even for 24-bit output. */ |
| 110 a += a*2.4e-7; |
| 111 if (x[i*C]>0) |
| 112 a = -a; |
| 113 /* Apply soft clipping */ |
| 114 for (i=start;i<end;i++) |
| 115 x[i*C] = x[i*C]+a*x[i*C]*x[i*C]; |
| 116 |
| 117 if (special && peak_pos>=2) |
| 118 { |
| 119 /* Add a linear ramp from the first sample to the signal peak. |
| 120 This avoids a discontinuity at the beginning of the frame. */ |
| 121 float delta; |
| 122 float offset = x0-x[0]; |
| 123 delta = offset / peak_pos; |
| 124 for (i=curr;i<peak_pos;i++) |
| 125 { |
| 126 offset -= delta; |
| 127 x[i*C] += offset; |
| 128 x[i*C] = MAX16(-1.f, MIN16(1.f, x[i*C])); |
| 129 } |
| 130 } |
| 131 curr = end; |
| 132 if (curr==N) |
| 133 break; |
| 134 } |
| 135 declip_mem[c] = a; |
| 136 } |
| 137 } |
| 138 #endif |
| 139 |
| 140 int encode_size(int size, unsigned char *data) |
| 141 { |
| 142 if (size < 252) |
| 143 { |
| 144 data[0] = size; |
| 145 return 1; |
| 146 } else { |
| 147 data[0] = 252+(size&0x3); |
| 148 data[1] = (size-(int)data[0])>>2; |
| 149 return 2; |
| 150 } |
| 151 } |
| 152 |
| 153 static int parse_size(const unsigned char *data, opus_int32 len, opus_int16 *siz
e) |
| 154 { |
| 155 if (len<1) |
| 156 { |
| 157 *size = -1; |
| 158 return -1; |
| 159 } else if (data[0]<252) |
| 160 { |
| 161 *size = data[0]; |
| 162 return 1; |
| 163 } else if (len<2) |
| 164 { |
| 165 *size = -1; |
| 166 return -1; |
| 167 } else { |
| 168 *size = 4*data[1] + data[0]; |
| 169 return 2; |
| 170 } |
| 171 } |
| 172 |
| 173 int opus_packet_get_samples_per_frame(const unsigned char *data, |
| 174 opus_int32 Fs) |
| 175 { |
| 176 int audiosize; |
| 177 if (data[0]&0x80) |
| 178 { |
| 179 audiosize = ((data[0]>>3)&0x3); |
| 180 audiosize = (Fs<<audiosize)/400; |
| 181 } else if ((data[0]&0x60) == 0x60) |
| 182 { |
| 183 audiosize = (data[0]&0x08) ? Fs/50 : Fs/100; |
| 184 } else { |
| 185 audiosize = ((data[0]>>3)&0x3); |
| 186 if (audiosize == 3) |
| 187 audiosize = Fs*60/1000; |
| 188 else |
| 189 audiosize = (Fs<<audiosize)/100; |
| 190 } |
| 191 return audiosize; |
| 192 } |
| 193 |
| 194 int opus_packet_parse_impl(const unsigned char *data, opus_int32 len, |
| 195 int self_delimited, unsigned char *out_toc, |
| 196 const unsigned char *frames[48], opus_int16 size[48], |
| 197 int *payload_offset, opus_int32 *packet_offset) |
| 198 { |
| 199 int i, bytes; |
| 200 int count; |
| 201 int cbr; |
| 202 unsigned char ch, toc; |
| 203 int framesize; |
| 204 opus_int32 last_size; |
| 205 opus_int32 pad = 0; |
| 206 const unsigned char *data0 = data; |
| 207 |
| 208 if (size==NULL || len<0) |
| 209 return OPUS_BAD_ARG; |
| 210 if (len==0) |
| 211 return OPUS_INVALID_PACKET; |
| 212 |
| 213 framesize = opus_packet_get_samples_per_frame(data, 48000); |
| 214 |
| 215 cbr = 0; |
| 216 toc = *data++; |
| 217 len--; |
| 218 last_size = len; |
| 219 switch (toc&0x3) |
| 220 { |
| 221 /* One frame */ |
| 222 case 0: |
| 223 count=1; |
| 224 break; |
| 225 /* Two CBR frames */ |
| 226 case 1: |
| 227 count=2; |
| 228 cbr = 1; |
| 229 if (!self_delimited) |
| 230 { |
| 231 if (len&0x1) |
| 232 return OPUS_INVALID_PACKET; |
| 233 last_size = len/2; |
| 234 /* If last_size doesn't fit in size[0], we'll catch it later */ |
| 235 size[0] = (opus_int16)last_size; |
| 236 } |
| 237 break; |
| 238 /* Two VBR frames */ |
| 239 case 2: |
| 240 count = 2; |
| 241 bytes = parse_size(data, len, size); |
| 242 len -= bytes; |
| 243 if (size[0]<0 || size[0] > len) |
| 244 return OPUS_INVALID_PACKET; |
| 245 data += bytes; |
| 246 last_size = len-size[0]; |
| 247 break; |
| 248 /* Multiple CBR/VBR frames (from 0 to 120 ms) */ |
| 249 default: /*case 3:*/ |
| 250 if (len<1) |
| 251 return OPUS_INVALID_PACKET; |
| 252 /* Number of frames encoded in bits 0 to 5 */ |
| 253 ch = *data++; |
| 254 count = ch&0x3F; |
| 255 if (count <= 0 || framesize*count > 5760) |
| 256 return OPUS_INVALID_PACKET; |
| 257 len--; |
| 258 /* Padding flag is bit 6 */ |
| 259 if (ch&0x40) |
| 260 { |
| 261 int p; |
| 262 do { |
| 263 int tmp; |
| 264 if (len<=0) |
| 265 return OPUS_INVALID_PACKET; |
| 266 p = *data++; |
| 267 len--; |
| 268 tmp = p==255 ? 254: p; |
| 269 len -= tmp; |
| 270 pad += tmp; |
| 271 } while (p==255); |
| 272 } |
| 273 if (len<0) |
| 274 return OPUS_INVALID_PACKET; |
| 275 /* VBR flag is bit 7 */ |
| 276 cbr = !(ch&0x80); |
| 277 if (!cbr) |
| 278 { |
| 279 /* VBR case */ |
| 280 last_size = len; |
| 281 for (i=0;i<count-1;i++) |
| 282 { |
| 283 bytes = parse_size(data, len, size+i); |
| 284 len -= bytes; |
| 285 if (size[i]<0 || size[i] > len) |
| 286 return OPUS_INVALID_PACKET; |
| 287 data += bytes; |
| 288 last_size -= bytes+size[i]; |
| 289 } |
| 290 if (last_size<0) |
| 291 return OPUS_INVALID_PACKET; |
| 292 } else if (!self_delimited) |
| 293 { |
| 294 /* CBR case */ |
| 295 last_size = len/count; |
| 296 if (last_size*count!=len) |
| 297 return OPUS_INVALID_PACKET; |
| 298 for (i=0;i<count-1;i++) |
| 299 size[i] = (opus_int16)last_size; |
| 300 } |
| 301 break; |
| 302 } |
| 303 /* Self-delimited framing has an extra size for the last frame. */ |
| 304 if (self_delimited) |
| 305 { |
| 306 bytes = parse_size(data, len, size+count-1); |
| 307 len -= bytes; |
| 308 if (size[count-1]<0 || size[count-1] > len) |
| 309 return OPUS_INVALID_PACKET; |
| 310 data += bytes; |
| 311 /* For CBR packets, apply the size to all the frames. */ |
| 312 if (cbr) |
| 313 { |
| 314 if (size[count-1]*count > len) |
| 315 return OPUS_INVALID_PACKET; |
| 316 for (i=0;i<count-1;i++) |
| 317 size[i] = size[count-1]; |
| 318 } else if (bytes+size[count-1] > last_size) |
| 319 return OPUS_INVALID_PACKET; |
| 320 } else |
| 321 { |
| 322 /* Because it's not encoded explicitly, it's possible the size of the |
| 323 last packet (or all the packets, for the CBR case) is larger than |
| 324 1275. Reject them here.*/ |
| 325 if (last_size > 1275) |
| 326 return OPUS_INVALID_PACKET; |
| 327 size[count-1] = (opus_int16)last_size; |
| 328 } |
| 329 |
| 330 if (payload_offset) |
| 331 *payload_offset = (int)(data-data0); |
| 332 |
| 333 for (i=0;i<count;i++) |
| 334 { |
| 335 if (frames) |
| 336 frames[i] = data; |
| 337 data += size[i]; |
| 338 } |
| 339 |
| 340 if (packet_offset) |
| 341 *packet_offset = pad+(opus_int32)(data-data0); |
| 342 |
| 343 if (out_toc) |
| 344 *out_toc = toc; |
| 345 |
| 346 return count; |
| 347 } |
| 348 |
| 349 int opus_packet_parse(const unsigned char *data, opus_int32 len, |
| 350 unsigned char *out_toc, const unsigned char *frames[48], |
| 351 opus_int16 size[48], int *payload_offset) |
| 352 { |
| 353 return opus_packet_parse_impl(data, len, 0, out_toc, |
| 354 frames, size, payload_offset, NULL); |
| 355 } |
| 356 |
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