blob: 2eb6bfc467a44ee10f0556bb188d361f875d378d (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_AUDIO_PUSH_FIFO_H_
#define MEDIA_BASE_AUDIO_PUSH_FIFO_H_
#include <memory>
#include "base/callback.h"
#include "base/macros.h"
#include "media/base/audio_bus.h"
#include "media/base/media_export.h"
namespace media {
// Yet another FIFO for audio data that re-buffers audio to a desired buffer
// size. Unlike AudioFifo and AudioBlockFifo, this FIFO cannot overflow: The
// client is required to provide a callback that is called synchronously during
// a push whenever enough data becomes available. This implementation
// eliminates redundant memory copies when the input buffer size always matches
// the desired buffer size.
class MEDIA_EXPORT AudioPushFifo final {
public:
// Called synchronously zero, one, or multiple times during a call to Push()
// to deliver re-buffered audio. |frame_delay| refers to the position of the
// first frame in |output| relative to the first frame in the Push() call. If
// negative, this indicates the output contains some data from a prior call to
// Push(). If zero or positive, the output contains data from the current
// call to Push(). Clients can use this to adjust timestamps.
using OutputCallback =
base::RepeatingCallback<void(const AudioBus& output_bus,
int frame_delay)>;
// Creates a new AudioPushFifo which delivers re-buffered audio by running
// |callback|.
explicit AudioPushFifo(const OutputCallback& callback);
~AudioPushFifo();
// Returns the number of frames in each AudioBus delivered to the
// OutputCallback.
int frames_per_buffer() const { return frames_per_buffer_; }
// Must be called at least once before the first call to Push(). May be
// called later (e.g., to support an audio format change).
void Reset(int frames_per_buffer);
// Pushes all audio channel data from |input_bus| through the FIFO. This will
// result in zero, one, or multiple synchronous calls to the OutputCallback
// provided in the constructor. If the |input_bus| has a different number of
// channels than the prior Push() call, any currently-queued frames will be
// dropped.
void Push(const AudioBus& input_bus);
// Flushes any enqueued frames by invoking the OutputCallback with those
// frames plus padded zero samples. If there are no frames currently
// enqueued, OutputCallback is not run.
void Flush();
private:
const OutputCallback callback_;
int frames_per_buffer_;
// Queue of frames pending for delivery.
std::unique_ptr<AudioBus> audio_queue_;
int queued_frames_;
DISALLOW_COPY_AND_ASSIGN(AudioPushFifo);
};
} // namespace media
#endif // MEDIA_BASE_AUDIO_PUSH_FIFO_H_
|
