| 1 | /* |
| 2 | * This file is part of DisOrder. |
| 3 | * Copyright (C) 2009 Richard Kettlewell |
| 4 | * |
| 5 | * This program is free software: you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation, either version 3 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | */ |
| 18 | |
| 19 | /** @file lib/resample.c |
| 20 | * @brief Audio resampling |
| 21 | * |
| 22 | * General purpose audio format conversion. Rate conversion only works if the |
| 23 | * SRC samplerate library is available, but the bitness/channel/endianness |
| 24 | * conversion works regardless. |
| 25 | */ |
| 26 | |
| 27 | #include "common.h" |
| 28 | #include "resample.h" |
| 29 | #include "log.h" |
| 30 | #include "mem.h" |
| 31 | |
| 32 | /** @brief Number of intermediate-format samples */ |
| 33 | #define SAMPLES 1024 |
| 34 | |
| 35 | /** @brief Multiplier for signed formats to allow easy switching */ |
| 36 | #define SIGNED 4 |
| 37 | |
| 38 | /** @brief Initialize a resampler |
| 39 | * @param rs Resampler |
| 40 | * @param input_bits Bits/sample in input |
| 41 | * @param input_channels Number of input channels |
| 42 | * @param input_signed Whether input samples are signed or unsigned |
| 43 | * @param input_rate Frames/second in input |
| 44 | * @param input_endian Input endianness (@c ENDIAN_BIG or @c ENDIAN_LITTLE) |
| 45 | * @param output_bits Bits/sample in output |
| 46 | * @param output_channels Number of output channels |
| 47 | * @param output_rate Frames/second in output |
| 48 | * @param output_signed Whether output samples are signed or unsigned |
| 49 | * @param output_endian Output endianness (@c ENDIAN_BIG or @c ENDIAN_LITTLE) |
| 50 | * |
| 51 | * For formats with more than two channels it's assume that the first |
| 52 | * two channels are left and right. No particular meaning is attached |
| 53 | * to additional channels other than to assume channel N in an input |
| 54 | * means the same as channel N in an output, for N>1. |
| 55 | */ |
| 56 | void resample_init(struct resampler *rs, |
| 57 | int input_bits, int input_channels, |
| 58 | int input_rate, int input_signed, |
| 59 | int input_endian, |
| 60 | int output_bits, int output_channels, |
| 61 | int output_rate, int output_signed, |
| 62 | int output_endian) { |
| 63 | memset(rs, 0, sizeof *rs); |
| 64 | assert(input_bits == 8 || input_bits == 16); |
| 65 | assert(output_bits == 8 || output_bits == 16); |
| 66 | assert(input_endian == ENDIAN_BIG || input_endian == ENDIAN_LITTLE); |
| 67 | assert(output_endian == ENDIAN_BIG || output_endian == ENDIAN_LITTLE); |
| 68 | assert(ENDIAN_BIG >= 0 && ENDIAN_BIG < SIGNED); |
| 69 | assert(ENDIAN_LITTLE >= 0 && ENDIAN_LITTLE < SIGNED); |
| 70 | rs->input_bits = input_bits; |
| 71 | rs->input_channels = input_channels; |
| 72 | rs->input_rate = input_rate; |
| 73 | rs->input_signed = SIGNED * !!input_signed; |
| 74 | rs->input_endian = input_endian; |
| 75 | rs->output_bits = output_bits; |
| 76 | rs->output_channels = output_channels; |
| 77 | rs->output_rate = output_rate; |
| 78 | rs->output_signed = SIGNED * !!output_signed; |
| 79 | rs->output_endian = output_endian; |
| 80 | rs->input_bytes_per_sample = (rs->input_bits + 7) / 8; |
| 81 | rs->input_bytes_per_frame = rs->input_channels * rs->input_bytes_per_sample; |
| 82 | if(rs->input_rate != rs->output_rate) { |
| 83 | #if HAVE_SAMPLERATE_H |
| 84 | int error_; |
| 85 | rs->state = src_new(SRC_SINC_BEST_QUALITY, rs->output_channels, &error_); |
| 86 | if(!rs->state) |
| 87 | disorder_fatal(0, "calling src_new: %s", src_strerror(error_)); |
| 88 | #else |
| 89 | disorder_fatal(0, "need to resample audio data but libsamplerate not available"); |
| 90 | #endif |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | /** @brief Destroy a resampler |
| 95 | * @param rs Resampler |
| 96 | */ |
| 97 | void resample_close(struct resampler *rs) { |
| 98 | #if HAVE_SAMPLERATE_H |
| 99 | if(rs->state) |
| 100 | src_delete(rs->state); |
| 101 | #else |
| 102 | if(rs){} /* quieten compiler */ |
| 103 | #endif |
| 104 | } |
| 105 | |
| 106 | /** @brief Get one sample value and normalize it to [-1,1] |
| 107 | * @param rs Resampler state |
| 108 | * @param bytes Pointer to input data |
| 109 | * @param where Where to store result |
| 110 | * @return Number of bytes consumed |
| 111 | */ |
| 112 | static size_t resample_get_sample(const struct resampler *rs, |
| 113 | const uint8_t *bytes, |
| 114 | float *where) { |
| 115 | switch(rs->input_bits + rs->input_signed + rs->input_endian) { |
| 116 | case 8+ENDIAN_BIG: |
| 117 | case 8+ENDIAN_LITTLE: |
| 118 | *where = (bytes[0] - 128)/ 128.0; |
| 119 | return 1; |
| 120 | case 8+SIGNED+ENDIAN_BIG: |
| 121 | case 8+SIGNED+ENDIAN_LITTLE: |
| 122 | *where = (int8_t)bytes[0] / 128.0; |
| 123 | return 1; |
| 124 | case 16+ENDIAN_BIG: |
| 125 | *where = (bytes[0] * 256 + bytes[1] - 32768)/ 32768.0; |
| 126 | return 2; |
| 127 | break; |
| 128 | case 16+ENDIAN_LITTLE: |
| 129 | *where = (bytes[1] * 256 + bytes[0] - 32768)/ 32768.0; |
| 130 | return 2; |
| 131 | break; |
| 132 | case 16+SIGNED+ENDIAN_BIG: |
| 133 | *where = (int16_t)(bytes[0] * 256 + bytes[1])/ 32768.0; |
| 134 | return 2; |
| 135 | break; |
| 136 | case 16+SIGNED+ENDIAN_LITTLE: |
| 137 | *where = (int16_t)(bytes[1] * 256 + bytes[0])/ 32768.0; |
| 138 | return 2; |
| 139 | break; |
| 140 | default: |
| 141 | assert(!"unsupported sample format"); |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | static inline int clip(int n, int min, int max) { |
| 146 | if(n >= min) { |
| 147 | if(n <= max) |
| 148 | return n; |
| 149 | else |
| 150 | return max; |
| 151 | } else |
| 152 | return min; |
| 153 | } |
| 154 | |
| 155 | /** @brief Store one sample value |
| 156 | * @param rs Resampler state |
| 157 | * @param sample Sample value |
| 158 | * @param bytes Where to store it |
| 159 | * @return Number of bytes stored |
| 160 | * |
| 161 | * The value is clipped naively if it will not fit. |
| 162 | */ |
| 163 | static size_t resample_put_sample(const struct resampler *rs, |
| 164 | float sample, |
| 165 | uint8_t *bytes) { |
| 166 | unsigned value; |
| 167 | switch(rs->output_bits + rs->output_signed + rs->output_endian) { |
| 168 | case 8+ENDIAN_BIG: |
| 169 | case 8+ENDIAN_LITTLE: |
| 170 | *bytes = clip(sample * 128.0 + 128, 0, 255); |
| 171 | return 1; |
| 172 | case 8+SIGNED+ENDIAN_BIG: |
| 173 | case 8+SIGNED+ENDIAN_LITTLE: |
| 174 | *bytes = clip((int)(sample * 128.0), -128, 127); |
| 175 | return 1; |
| 176 | case 16+ENDIAN_BIG: /* unsigned */ |
| 177 | value = clip(sample * 32768.0 + 32768, 0, 65535); |
| 178 | *bytes++ = value >> 8; |
| 179 | *bytes++ = value; |
| 180 | return 2; |
| 181 | case 16+ENDIAN_LITTLE: |
| 182 | value = clip(sample * 32768.0 + 32768, 0, 65535); |
| 183 | *bytes++ = value; |
| 184 | *bytes++ = value >> 8; |
| 185 | return 2; |
| 186 | case 16+SIGNED+ENDIAN_BIG: |
| 187 | value = clip(sample * 32768.0, -32768, 32767); |
| 188 | *bytes++ = value >> 8; |
| 189 | *bytes++ = value; |
| 190 | return 2; |
| 191 | case 16+SIGNED+ENDIAN_LITTLE: |
| 192 | value = clip(sample * 32768.0, -32768, 32767); |
| 193 | *bytes++ = value; |
| 194 | *bytes++ = value >> 8; |
| 195 | return 2; |
| 196 | default: |
| 197 | assert(!"unsupported sample format"); |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | /** @brief Convert input samples to floats |
| 202 | * @param rs Resampler state |
| 203 | * @param bytes Input bytes |
| 204 | * @param nframes Number of input frames |
| 205 | * @param floats Where to store converted data |
| 206 | * |
| 207 | * @p floats must be big enough. As well as converting to floats this |
| 208 | * also converts to the output's channel format. |
| 209 | * |
| 210 | * Excess input channels are just discarded. If there are insufficient input |
| 211 | * channels the last one is duplicated as often as necessary to make up the |
| 212 | * numbers. This is a rather naff heuristic and may be improved in a future |
| 213 | * version, but mostly in DisOrder the output is pretty much always stereo and |
| 214 | * the input either mono or stereo, so the result isn't actually going to be |
| 215 | * too bad. |
| 216 | */ |
| 217 | static void resample_prepare_input(const struct resampler *rs, |
| 218 | const uint8_t *bytes, |
| 219 | size_t nframes, |
| 220 | float *floats) { |
| 221 | while(nframes > 0) { |
| 222 | int n; |
| 223 | |
| 224 | for(n = 0; n < rs->input_channels && n < rs->output_channels; ++n) { |
| 225 | bytes += resample_get_sample(rs, bytes, floats); |
| 226 | ++floats; |
| 227 | } |
| 228 | if(n < rs->input_channels) { |
| 229 | /* More input channels; discard them */ |
| 230 | bytes += (rs->input_channels - n) * rs->input_bytes_per_sample; |
| 231 | } else if(n < rs->output_channels) { |
| 232 | /* More output channels; duplicate the last input channel */ |
| 233 | for(; n < rs->output_channels; ++n) { |
| 234 | *floats = floats[-1]; |
| 235 | ++floats; |
| 236 | } |
| 237 | } |
| 238 | --nframes; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | /** @brief Convert between sample formats |
| 243 | * @param rs Resampler state |
| 244 | * @param bytes Bytes to convert |
| 245 | * @param nbytes Number of bytes to convert |
| 246 | * @param eof Set an end of input stream |
| 247 | * @param converted Called with converted data (possibly more than once) |
| 248 | * @param cd Passed to @p cd |
| 249 | * @return Number of bytes consumed |
| 250 | */ |
| 251 | size_t resample_convert(const struct resampler *rs, |
| 252 | const uint8_t *bytes, |
| 253 | size_t nbytes, |
| 254 | int eof, |
| 255 | void (*converted)(uint8_t *bytes, |
| 256 | size_t nbytes, |
| 257 | void *cd), |
| 258 | void *cd) { |
| 259 | size_t nframesin = nbytes / (rs->input_bytes_per_frame); |
| 260 | size_t nsamplesout; |
| 261 | float *input = xcalloc(nframesin * rs->output_channels, sizeof (float)); |
| 262 | float *output = 0; |
| 263 | |
| 264 | resample_prepare_input(rs, bytes, nframesin, input); |
| 265 | #if HAVE_SAMPLERATE_H |
| 266 | if(rs->state) { |
| 267 | /* A sample-rate conversion must be performed */ |
| 268 | SRC_DATA data; |
| 269 | memset(&data, 0, sizeof data); |
| 270 | /* Compute how many frames are expected to come out. */ |
| 271 | size_t maxframesout = nframesin * rs->output_rate / rs->input_rate + 1; |
| 272 | output = xcalloc(maxframesout * rs->output_channels, sizeof(float)); |
| 273 | data.data_in = input; |
| 274 | data.data_out = output; |
| 275 | data.input_frames = nframesin; |
| 276 | data.output_frames = maxframesout; |
| 277 | data.end_of_input = eof; |
| 278 | data.src_ratio = (double)rs->output_rate / rs->input_rate; |
| 279 | D(("nframesin=%zu maxframesout=%zu eof=%d ratio=%d.%06d", |
| 280 | nframesin, maxframesout, eof, |
| 281 | (int)data.src_ratio, |
| 282 | ((int)(data.src_ratio * 1000000) % 1000000))); |
| 283 | int error_ = src_process(rs->state, &data); |
| 284 | if(error_) |
| 285 | disorder_fatal(0, "calling src_process: %s", src_strerror(error_)); |
| 286 | nframesin = data.input_frames_used; |
| 287 | nsamplesout = data.output_frames_gen * rs->output_channels; |
| 288 | D(("new nframesin=%zu nsamplesout=%zu", nframesin, nsamplesout)); |
| 289 | } |
| 290 | #endif |
| 291 | if(!output) { |
| 292 | /* No sample-rate conversion required */ |
| 293 | output = input; |
| 294 | nsamplesout = nframesin * rs->output_channels; |
| 295 | } |
| 296 | const float *op = output; |
| 297 | while(nsamplesout > 0) { |
| 298 | uint8_t buffer[4096]; |
| 299 | size_t bufused = 0; |
| 300 | |
| 301 | while(bufused < sizeof buffer && nsamplesout > 0) { |
| 302 | bufused += resample_put_sample(rs, *op++, buffer + bufused); |
| 303 | --nsamplesout; |
| 304 | } |
| 305 | converted(buffer, bufused, cd); |
| 306 | } |
| 307 | if(output != input) |
| 308 | xfree(output); |
| 309 | xfree(input); |
| 310 | if(eof){} /* quieten compiler */ |
| 311 | /* Report how many input bytes were actually consumed */ |
| 312 | //fprintf(stderr, "converted %zu frames\n", nframesin); |
| 313 | return nframesin * rs->input_bytes_per_frame; |
| 314 | } |
| 315 | |
| 316 | /* |
| 317 | Local Variables: |
| 318 | c-basic-offset:2 |
| 319 | comment-column:40 |
| 320 | fill-column:79 |
| 321 | indent-tabs-mode:nil |
| 322 | End: |
| 323 | */ |