Index: media/base/audio_push_fifo.cc |
diff --git a/media/base/audio_push_fifo.cc b/media/base/audio_push_fifo.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..5e759670b6bc392c7e873e426768c864e5319e97 |
--- /dev/null |
+++ b/media/base/audio_push_fifo.cc |
@@ -0,0 +1,86 @@ |
+// 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. |
+ |
+#include "media/base/audio_push_fifo.h" |
+ |
+#include <algorithm> |
+ |
+#include "base/logging.h" |
+ |
+namespace media { |
+ |
+AudioPushFifo::AudioPushFifo(const OutputCallback& callback) |
+ : callback_(callback), frames_per_buffer_(0) { |
+ DCHECK(!callback_.is_null()); |
+} |
+ |
+AudioPushFifo::~AudioPushFifo() {} |
+ |
+void AudioPushFifo::Reset(int frames_per_buffer) { |
+ DCHECK_GT(frames_per_buffer, 0); |
+ |
+ audio_queue_.reset(); |
+ queued_frames_ = 0; |
+ |
+ frames_per_buffer_ = frames_per_buffer; |
+} |
+ |
+void AudioPushFifo::Push(const AudioBus& input_bus) { |
+ DCHECK_GT(frames_per_buffer_, 0); |
+ |
+ // Fast path: No buffering required. |
+ if ((queued_frames_ == 0) && (input_bus.frames() == frames_per_buffer_)) { |
+ callback_.Run(input_bus, 0); |
+ return; |
+ } |
+ |
+ // Lazy-create the |audio_queue_| if needed. |
+ if (!audio_queue_ || audio_queue_->channels() != input_bus.channels()) |
+ audio_queue_ = AudioBus::Create(input_bus.channels(), frames_per_buffer_); |
+ |
+ // Start with a frame offset that refers to the position of the first sample |
+ // in |audio_queue_| relative to the first sample in |input_bus|. |
+ int frame_delay = -queued_frames_; |
+ |
+ // Repeatedly fill up |audio_queue_| with more sample frames from |input_bus| |
+ // and deliver batches until all sample frames in |input_bus| have been |
+ // consumed. |
+ int input_offset = 0; |
+ do { |
+ // Attempt to fill |audio_queue_| completely. |
+ const int frames_to_enqueue = |
+ std::min(static_cast<int>(input_bus.frames() - input_offset), |
+ frames_per_buffer_ - queued_frames_); |
+ if (frames_to_enqueue > 0) { |
+ DVLOG(2) << "Enqueuing " << frames_to_enqueue << " frames."; |
+ input_bus.CopyPartialFramesTo(input_offset, frames_to_enqueue, |
+ queued_frames_, audio_queue_.get()); |
+ queued_frames_ += frames_to_enqueue; |
+ input_offset += frames_to_enqueue; |
+ } |
+ |
+ // If |audio_queue_| has been filled completely, deliver the re-buffered |
+ // audio to the consumer. |
+ if (queued_frames_ == frames_per_buffer_) { |
+ DVLOG(2) << "Delivering another " << queued_frames_ << " frames."; |
+ callback_.Run(*audio_queue_, frame_delay); |
+ frame_delay += frames_per_buffer_; |
+ queued_frames_ = 0; |
+ } else { |
+ // Not enough frames queued-up yet to deliver more frames. |
+ } |
+ } while (input_offset < input_bus.frames()); |
+} |
+ |
+void AudioPushFifo::Flush() { |
+ if (queued_frames_ == 0) |
+ return; |
+ |
+ audio_queue_->ZeroFramesPartial(queued_frames_, |
+ audio_queue_->frames() - queued_frames_); |
+ callback_.Run(*audio_queue_, -queued_frames_); |
+ queued_frames_ = 0; |
+} |
+ |
+} // namespace media |