123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778 |
- // 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 "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(const AudioPushFifo&) = delete;
- AudioPushFifo& operator=(const AudioPushFifo&) = delete;
- ~AudioPushFifo();
- // Returns the number of frames in each AudioBus delivered to the
- // OutputCallback.
- int frames_per_buffer() const { return frames_per_buffer_; }
- // The number of frames currently queued in this FIFO.
- int queued_frames() const { return queued_frames_; }
- // 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_;
- };
- } // namespace media
- #endif // MEDIA_BASE_AUDIO_PUSH_FIFO_H_
|