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76 lines
2.2 KiB
76 lines
2.2 KiB
13 years ago
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/*
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* Copyright 2012 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Create a WAV file
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#include "wavout.h"
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using namespace std;
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void w32le(char *buf, int offset, int32_t val) {
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buf[offset + 0] = val & 0xff;
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buf[offset + 1] = (val >> 8) & 0xff;
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buf[offset + 2] = (val >> 16) & 0xff;
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buf[offset + 3] = (val >> 24) & 0xff;
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}
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void w16le(char *buf, int offset, int val) {
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buf[offset + 0] = val & 0xff;
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buf[offset + 1] = (val >> 8) & 0xff;
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}
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void w4cc(char *buf, int offset, const char *s) {
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for (int i = 0; i < 4; i++) {
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buf[offset + i] = s[i];
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}
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}
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WavOut::WavOut(const char *filename, double sample_rate, int n_samples) {
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char header[44];
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fs = new fstream(filename, fstream::out | fstream::trunc | fstream::binary);
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w4cc(header, 0, "RIFF");
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w32le(header, 4, 36 + 2 * n_samples);
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w4cc(header, 8, "WAVE");
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w4cc(header, 12, "fmt ");
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w32le(header, 16, 16);
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w16le(header, 20, 1); // AudioFormat
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w16le(header, 22, 1); // NumChannels
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w32le(header, 24, (int32_t)sample_rate);
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w32le(header, 28, 2 * (int32_t)sample_rate);
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w16le(header, 32, 2); // BlockAlign
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w16le(header, 34, 16); // BitsPerSample
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w4cc(header, 36, "data");
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w32le(header, 40, 2 * n_samples);
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fs->write(header, 44);
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}
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void WavOut::write_data(const int32_t *buf, int n) {
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int32_t delta = 0x100;
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for (int i = 0; i < n; i++) {
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int32_t val = buf[i];
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int clip_val = val < -(1 << 24) ? 0x8000 : (val >= (1 << 24) ? 0x7fff :
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(val + delta) >> 9);
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delta = (delta + val) & 0x1ff;
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sample_buf[i * 2] = clip_val & 0xff;
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sample_buf[i * 2 + 1] = (clip_val >> 8) & 0xff;
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}
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fs->write(sample_buf, n * 2);
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}
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void WavOut::close() {
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fs->close();
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}
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