1 /*
2 * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #include "modules/audio_coding/neteq/tools/audio_loop.h"
12
13 #include <stdio.h>
14 #include <string.h>
15
16 namespace webrtc {
17 namespace test {
18
Init(const std::string file_name,size_t max_loop_length_samples,size_t block_length_samples)19 bool AudioLoop::Init(const std::string file_name,
20 size_t max_loop_length_samples,
21 size_t block_length_samples) {
22 FILE* fp = fopen(file_name.c_str(), "rb");
23 if (!fp)
24 return false;
25
26 audio_array_.reset(
27 new int16_t[max_loop_length_samples + block_length_samples]);
28 size_t samples_read =
29 fread(audio_array_.get(), sizeof(int16_t), max_loop_length_samples, fp);
30 fclose(fp);
31
32 // Block length must be shorter than the loop length.
33 if (block_length_samples > samples_read)
34 return false;
35
36 // Add an extra block length of samples to the end of the array, starting
37 // over again from the beginning of the array. This is done to simplify
38 // the reading process when reading over the end of the loop.
39 memcpy(&audio_array_[samples_read], audio_array_.get(),
40 block_length_samples * sizeof(int16_t));
41
42 loop_length_samples_ = samples_read;
43 block_length_samples_ = block_length_samples;
44 next_index_ = 0;
45 return true;
46 }
47
GetNextBlock()48 rtc::ArrayView<const int16_t> AudioLoop::GetNextBlock() {
49 // Check that the AudioLoop is initialized.
50 if (block_length_samples_ == 0)
51 return rtc::ArrayView<const int16_t>();
52
53 const int16_t* output_ptr = &audio_array_[next_index_];
54 next_index_ = (next_index_ + block_length_samples_) % loop_length_samples_;
55 return rtc::ArrayView<const int16_t>(output_ptr, block_length_samples_);
56 }
57
58 } // namespace test
59 } // namespace webrtc
60