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| 1 // Copyright 2016 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 "media/base/audio_push_fifo.h" |
| 6 |
| 7 #include <algorithm> |
| 8 |
| 9 #include "base/logging.h" |
| 10 |
| 11 namespace media { |
| 12 |
| 13 AudioPushFifo::AudioPushFifo(const OutputCallback& callback) |
| 14 : callback_(callback), frames_per_buffer_(0) { |
| 15 DCHECK(!callback_.is_null()); |
| 16 } |
| 17 |
| 18 AudioPushFifo::~AudioPushFifo() {} |
| 19 |
| 20 void AudioPushFifo::Reset(int frames_per_buffer) { |
| 21 DCHECK_GT(frames_per_buffer, 0); |
| 22 |
| 23 audio_queue_.reset(); |
| 24 queued_frames_ = 0; |
| 25 |
| 26 frames_per_buffer_ = frames_per_buffer; |
| 27 } |
| 28 |
| 29 void AudioPushFifo::Push(const AudioBus& input_bus) { |
| 30 DCHECK_GT(frames_per_buffer_, 0); |
| 31 |
| 32 // Fast path: No buffering required. |
| 33 if ((queued_frames_ == 0) && (input_bus.frames() == frames_per_buffer_)) { |
| 34 callback_.Run(input_bus, 0); |
| 35 return; |
| 36 } |
| 37 |
| 38 // Lazy-create the |audio_queue_| if needed. |
| 39 if (!audio_queue_ || audio_queue_->channels() != input_bus.channels()) |
| 40 audio_queue_ = AudioBus::Create(input_bus.channels(), frames_per_buffer_); |
| 41 |
| 42 // Start with a frame offset that refers to the position of the first sample |
| 43 // in |audio_queue_| relative to the first sample in |input_bus|. |
| 44 int frame_delay = -queued_frames_; |
| 45 |
| 46 // Repeatedly fill up |audio_queue_| with more sample frames from |input_bus| |
| 47 // and deliver batches until all sample frames in |input_bus| have been |
| 48 // consumed. |
| 49 int input_offset = 0; |
| 50 do { |
| 51 // Attempt to fill |audio_queue_| completely. |
| 52 const int frames_to_enqueue = |
| 53 std::min(static_cast<int>(input_bus.frames() - input_offset), |
| 54 frames_per_buffer_ - queued_frames_); |
| 55 if (frames_to_enqueue > 0) { |
| 56 DVLOG(2) << "Enqueuing " << frames_to_enqueue << " frames."; |
| 57 input_bus.CopyPartialFramesTo(input_offset, frames_to_enqueue, |
| 58 queued_frames_, audio_queue_.get()); |
| 59 queued_frames_ += frames_to_enqueue; |
| 60 input_offset += frames_to_enqueue; |
| 61 } |
| 62 |
| 63 // If |audio_queue_| has been filled completely, deliver the re-buffered |
| 64 // audio to the consumer. |
| 65 if (queued_frames_ == frames_per_buffer_) { |
| 66 DVLOG(2) << "Delivering another " << queued_frames_ << " frames."; |
| 67 callback_.Run(*audio_queue_, frame_delay); |
| 68 frame_delay += frames_per_buffer_; |
| 69 queued_frames_ = 0; |
| 70 } else { |
| 71 // Not enough frames queued-up yet to deliver more frames. |
| 72 } |
| 73 } while (input_offset < input_bus.frames()); |
| 74 } |
| 75 |
| 76 void AudioPushFifo::Flush() { |
| 77 if (queued_frames_ == 0) |
| 78 return; |
| 79 |
| 80 audio_queue_->ZeroFramesPartial(queued_frames_, |
| 81 audio_queue_->frames() - queued_frames_); |
| 82 callback_.Run(*audio_queue_, -queued_frames_); |
| 83 queued_frames_ = 0; |
| 84 } |
| 85 |
| 86 } // namespace media |
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