1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "webkit/glue/media/audio_decoder.h"
6
7 #include <vector>
8 #include "base/basictypes.h"
9 #include "base/string_util.h"
10 #include "base/time.h"
11 #include "media/filters/audio_file_reader.h"
12 #include "third_party/WebKit/Source/WebKit/chromium/public/WebAudioBus.h"
13
14 using media::AudioFileReader;
15 using media::InMemoryDataReader;
16 using std::vector;
17 using WebKit::WebAudioBus;
18
19 namespace webkit_glue {
20
21 // Decode in-memory audio file data.
DecodeAudioFileData(WebKit::WebAudioBus * destination_bus,const char * data,size_t data_size,double sample_rate)22 bool DecodeAudioFileData(
23 WebKit::WebAudioBus* destination_bus,
24 const char* data, size_t data_size, double sample_rate) {
25 DCHECK(destination_bus);
26 if (!destination_bus)
27 return false;
28
29 // Uses the FFmpeg library for audio file reading.
30 InMemoryDataReader data_reader(data, data_size);
31 AudioFileReader reader(&data_reader);
32
33 if (!reader.Open())
34 return false;
35
36 size_t number_of_channels = reader.channels();
37 double file_sample_rate = reader.sample_rate();
38 double duration = reader.duration().InSecondsF();
39 size_t number_of_frames = static_cast<size_t>(reader.number_of_frames());
40
41 // TODO(crogers) : do sample-rate conversion with FFmpeg.
42 // For now, we're ignoring the requested 'sample_rate' and returning
43 // the WebAudioBus at the file's sample-rate.
44 // double destination_sample_rate =
45 // (sample_rate != 0.0) ? sample_rate : file_sample_rate;
46 double destination_sample_rate = file_sample_rate;
47
48 DLOG(INFO) << "Decoding file data -"
49 << " data: " << data
50 << " data size: " << data_size
51 << " duration: " << duration
52 << " number of frames: " << number_of_frames
53 << " sample rate: " << file_sample_rate
54 << " number of channels: " << number_of_channels;
55
56 // Change to destination sample-rate.
57 number_of_frames = static_cast<size_t>(number_of_frames *
58 (destination_sample_rate / file_sample_rate));
59
60 // Allocate and configure the output audio channel data.
61 destination_bus->initialize(number_of_channels,
62 number_of_frames,
63 destination_sample_rate);
64
65 // Wrap the channel pointers which will receive the decoded PCM audio.
66 vector<float*> audio_data;
67 audio_data.reserve(number_of_channels);
68 for (size_t i = 0; i < number_of_channels; ++i) {
69 audio_data.push_back(destination_bus->channelData(i));
70 }
71
72 // Decode the audio file data.
73 return reader.Read(audio_data, number_of_frames);
74 }
75
76 } // namespace webkit_glue
77