| 1 | /* |
| 2 | * Copyright (C) 2013 nu774 |
| 3 | * For conditions of distribution and use, see copyright notice in COPYING |
| 4 | */ |
| 5 | #if HAVE_CONFIG_H |
| 6 | # include "config.h" |
| 7 | #endif |
| 8 | #if HAVE_STDINT_H |
| 9 | # include <stdint.h> |
| 10 | #endif |
| 11 | #include <stdlib.h> |
| 12 | #include <string.h> |
| 13 | #include <assert.h> |
| 14 | #include "pcm_reader.h" |
| 15 | #include "lpc.h" |
| 16 | |
| 17 | typedef int16_t sample_t; |
| 18 | |
| 19 | typedef struct buffer_t { |
| 20 | sample_t *data; |
| 21 | unsigned count; /* count in frames */ |
| 22 | unsigned capacity; /* size in bytes */ |
| 23 | } buffer_t; |
| 24 | |
| 25 | typedef struct extrapolater_t { |
| 26 | pcm_reader_vtbl_t *vtbl; |
| 27 | pcm_reader_t *src; |
| 28 | pcm_sample_description_t format; |
| 29 | buffer_t buffer[2]; |
| 30 | unsigned nbuffer; |
| 31 | int (*process)(struct extrapolater_t *, void *, unsigned); |
| 32 | } extrapolater_t; |
| 33 | |
| 34 | #define LPC_ORDER 32 |
| 35 | |
| 36 | static inline pcm_reader_t *get_source(pcm_reader_t *reader) |
| 37 | { |
| 38 | return ((extrapolater_t *)reader)->src; |
| 39 | } |
| 40 | |
| 41 | static const |
| 42 | pcm_sample_description_t *get_format(pcm_reader_t *reader) |
| 43 | { |
| 44 | return pcm_get_format(get_source(reader)); |
| 45 | } |
| 46 | |
| 47 | static int64_t get_length(pcm_reader_t *reader) |
| 48 | { |
| 49 | return pcm_get_length(get_source(reader)); |
| 50 | } |
| 51 | |
| 52 | static int64_t get_position(pcm_reader_t *reader) |
| 53 | { |
| 54 | return pcm_get_position(get_source(reader)); |
| 55 | } |
| 56 | |
| 57 | static int realloc_buffer(buffer_t *bp, size_t size) |
| 58 | { |
| 59 | if (bp->capacity < size) { |
| 60 | void *p = realloc(bp->data, size); |
| 61 | if (!p) return -1; |
| 62 | bp->data = p; |
| 63 | bp->capacity = size; |
| 64 | } |
| 65 | return 0; |
| 66 | } |
| 67 | |
| 68 | static void reverse_buffer(sample_t *data, unsigned nframes, unsigned nchannels) |
| 69 | { |
| 70 | unsigned i = 0, j = nchannels * (nframes - 1), n; |
| 71 | |
| 72 | for (; i < j; i += nchannels, j -= nchannels) { |
| 73 | for (n = 0; n < nchannels; ++n) { |
| 74 | sample_t tmp = data[i + n]; |
| 75 | data[i + n] = data[j + n]; |
| 76 | data[j + n] = tmp; |
| 77 | } |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | static int fetch(extrapolater_t *self, unsigned nframes) |
| 82 | { |
| 83 | const pcm_sample_description_t *sfmt = pcm_get_format(self->src); |
| 84 | buffer_t *bp = &self->buffer[self->nbuffer]; |
| 85 | int rc = 0; |
| 86 | |
| 87 | if (realloc_buffer(bp, nframes * sfmt->bytes_per_frame) == 0) { |
| 88 | rc = pcm_read_frames(self->src, bp->data, nframes); |
| 89 | if (rc > 0) bp->count = rc; |
| 90 | } |
| 91 | if (rc > 0) |
| 92 | self->nbuffer ^= 1; |
| 93 | return rc <= 0 ? 0 : bp->count; |
| 94 | } |
| 95 | |
| 96 | static int extrapolate(extrapolater_t *self, const buffer_t *bp, |
| 97 | void *dst, unsigned nframes) |
| 98 | { |
| 99 | const pcm_sample_description_t *sfmt = pcm_get_format(self->src); |
| 100 | unsigned i, n = sfmt->channels_per_frame; |
| 101 | float lpc[LPC_ORDER]; |
| 102 | |
| 103 | for (i = 0; i < n; ++i) { |
| 104 | vorbis_lpc_from_data(bp->data + i, lpc, bp->count, LPC_ORDER, n); |
| 105 | vorbis_lpc_predict(lpc, &bp->data[i + n * (bp->count - LPC_ORDER)], |
| 106 | LPC_ORDER, (sample_t*)dst + i, nframes, n); |
| 107 | } |
| 108 | return nframes; |
| 109 | } |
| 110 | |
| 111 | static int process1(extrapolater_t *self, void *buffer, unsigned nframes); |
| 112 | static int process2(extrapolater_t *self, void *buffer, unsigned nframes); |
| 113 | static int process3(extrapolater_t *self, void *buffer, unsigned nframes); |
| 114 | |
| 115 | static int process0(extrapolater_t *self, void *buffer, unsigned nframes) |
| 116 | { |
| 117 | const pcm_sample_description_t *sfmt = pcm_get_format(self->src); |
| 118 | unsigned nchannels = sfmt->channels_per_frame; |
| 119 | buffer_t *bp = &self->buffer[self->nbuffer]; |
| 120 | |
| 121 | if (fetch(self, nframes) < 2 * LPC_ORDER) |
| 122 | memset(buffer, 0, nframes * sfmt->bytes_per_frame); |
| 123 | else { |
| 124 | reverse_buffer(bp->data, bp->count, nchannels); |
| 125 | extrapolate(self, bp, buffer, nframes); |
| 126 | reverse_buffer(buffer, nframes, nchannels); |
| 127 | reverse_buffer(bp->data, bp->count, nchannels); |
| 128 | } |
| 129 | if (bp->count) |
| 130 | self->process = process1; |
| 131 | else { |
| 132 | memset(bp->data, 0, nframes * sfmt->bytes_per_frame); |
| 133 | bp->count = nframes; |
| 134 | self->process = process2; |
| 135 | } |
| 136 | return nframes; |
| 137 | } |
| 138 | |
| 139 | static int process1(extrapolater_t *self, void *buffer, unsigned nframes) |
| 140 | { |
| 141 | const pcm_sample_description_t *sfmt = pcm_get_format(self->src); |
| 142 | buffer_t *bp = &self->buffer[self->nbuffer ^ 1]; |
| 143 | |
| 144 | assert(bp->count <= nframes); |
| 145 | memcpy(buffer, bp->data, bp->count * sfmt->bytes_per_frame); |
| 146 | if (!fetch(self, nframes)) { |
| 147 | buffer_t *bbp = &self->buffer[self->nbuffer]; |
| 148 | if (bp->count < 2 * LPC_ORDER) { |
| 149 | size_t total = bp->count + bbp->count; |
| 150 | if (bbp->count && |
| 151 | realloc_buffer(bbp, total * sfmt->bytes_per_frame) == 0 && |
| 152 | realloc_buffer(bp, total * sfmt->bytes_per_frame) == 0) |
| 153 | { |
| 154 | memcpy(bbp->data + bbp->count * sfmt->channels_per_frame, |
| 155 | bp->data, bp->count * sfmt->bytes_per_frame); |
| 156 | memcpy(bp->data, bbp->data, total * sfmt->bytes_per_frame); |
| 157 | bp->count = total; |
| 158 | } |
| 159 | } |
| 160 | if (bp->count >= 2 * LPC_ORDER) |
| 161 | extrapolate(self, bp, bbp->data, nframes); |
| 162 | else |
| 163 | memset(bbp->data, 0, nframes * sfmt->bytes_per_frame); |
| 164 | bbp->count = nframes; |
| 165 | self->process = process2; |
| 166 | } |
| 167 | return bp->count; |
| 168 | } |
| 169 | |
| 170 | static int process2(extrapolater_t *self, void *buffer, unsigned nframes) |
| 171 | { |
| 172 | const pcm_sample_description_t *sfmt = pcm_get_format(self->src); |
| 173 | buffer_t *bp = &self->buffer[self->nbuffer]; |
| 174 | if (bp->count < nframes) |
| 175 | nframes = bp->count; |
| 176 | memcpy(buffer, bp->data, nframes * sfmt->bytes_per_frame); |
| 177 | if (bp->count > nframes) |
| 178 | memmove(bp->data, bp->data + nframes * sfmt->channels_per_frame, |
| 179 | (bp->count - nframes) * sfmt->bytes_per_frame); |
| 180 | bp->count -= nframes; |
| 181 | if (bp->count == 0) |
| 182 | self->process = process3; |
| 183 | return nframes; |
| 184 | } |
| 185 | |
| 186 | static int process3(extrapolater_t *self, void *buffer, unsigned nframes) |
| 187 | { |
| 188 | return 0; |
| 189 | } |
| 190 | |
| 191 | static int read_frames(pcm_reader_t *reader, void *buffer, unsigned nframes) |
| 192 | { |
| 193 | extrapolater_t *self = (extrapolater_t *)reader; |
| 194 | return self->process(self, buffer, nframes); |
| 195 | } |
| 196 | |
| 197 | static void teardown(pcm_reader_t **reader) |
| 198 | { |
| 199 | extrapolater_t *self = (extrapolater_t *)*reader; |
| 200 | pcm_teardown(&self->src); |
| 201 | free(self->buffer[0].data); |
| 202 | free(self->buffer[1].data); |
| 203 | free(self); |
| 204 | *reader = 0; |
| 205 | } |
| 206 | |
| 207 | static pcm_reader_vtbl_t my_vtable = { |
| 208 | get_format, get_length, get_position, read_frames, teardown |
| 209 | }; |
| 210 | |
| 211 | pcm_reader_t *extrapolater_open(pcm_reader_t *reader) |
| 212 | { |
| 213 | extrapolater_t *self = 0; |
| 214 | |
| 215 | if ((self = calloc(1, sizeof(extrapolater_t))) == 0) |
| 216 | return 0; |
| 217 | self->src = reader; |
| 218 | self->vtbl = &my_vtable; |
| 219 | self->process = process0; |
| 220 | return (pcm_reader_t *)self; |
| 221 | } |