Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 99 insertions, 0 deletions

diff --git a/dom/media/driftcontrol/AudioResampler.h b/dom/media/driftcontrol/AudioResampler.h
new file mode 100644
index 0000000000..20e4f1051b
--- /dev/null
+++ b/dom/media/driftcontrol/AudioResampler.h
@@ -0,0 +1,99 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DOM_MEDIA_DRIFTCONTROL_AUDIORESAMPLER_H_
+#define DOM_MEDIA_DRIFTCONTROL_AUDIORESAMPLER_H_
+
+#include "AudioChunkList.h"
+#include "AudioSegment.h"
+#include "DynamicResampler.h"
+#include "TimeUnits.h"
+
+namespace mozilla {
+
+/**
+ * Audio Resampler is a resampler able to change the output rate and channels
+ * count on the fly. The API is simple and it is based in AudioSegment in order
+ * to be used MTG. Memory allocations, for input and output buffers, will happen
+ * in the constructor, when channel count changes and if the amount of input
+ * data outgrows the input buffer. The memory is recycled in order to avoid
+ * reallocations. It also supports prebuffering of silence. It consists of
+ * DynamicResampler and AudioChunkList so please read their documentation if you
+ * are interested in more details.
+ *
+ * The output buffer is preallocated  and returned in the form of AudioSegment.
+ * The intention is to be used directly in a MediaTrack. Since an AudioChunk
+ * must no be "shared" in order to be written, the AudioSegment returned by
+ * resampler method must be cleaned up in order to be able for the `AudioChunk`s
+ * that it consists of to be reused. For `MediaTrack::mSegment` this happens
+ * every ~50ms (look at MediaTrack::AdvanceTimeVaryingValuesToCurrentTime). Thus
+ * memory capacity of 100ms has been preallocated for internal input and output
+ * buffering. Note that the amount of memory used for input buffering may
+ * increase if needed.
+ */
+class AudioResampler final {
+ public:
+  AudioResampler(uint32_t aInRate, uint32_t aOutRate,
+                 media::TimeUnit aPreBufferDuration,
+                 const PrincipalHandle& aPrincipalHandle);
+
+  /**
+   * Append input data into the resampler internal buffer. Copy/move of the
+   * memory is taking place. Also, the channel count will change according to
+   * the channel count of the chunks.
+   */
+  void AppendInput(const AudioSegment& aInSegment);
+  /**
+   * Get the number of frames that the internal input buffer can hold.
+   */
+  uint32_t InputCapacityFrames() const;
+  /**
+   * Get the number of frames that can be read from the internal input buffer
+   * before it becomes empty.
+   */
+  uint32_t InputReadableFrames() const;
+
+  /*
+   * Reguest `aOutFrames` of audio in the output sample rate. The internal
+   * buffered input is used. If the input buffer does not have enough data to
+   * reach `aOutFrames` frames, the input buffer is padded with enough silence
+   * to allow the requested frames to be resampled and returned, and the
+   * pre-buffer is reset so that the next call will be treated as the first.
+   *
+   * On first call, prepends the internal buffer with silence so that after
+   * resampling aOutFrames frames of data, the internal buffer holds input
+   * data as close as possible to the configured pre-buffer size.
+   */
+  AudioSegment Resample(uint32_t aOutFrames, bool* aHasUnderrun);
+
+  /*
+   * Updates the output rate that will be used by the resampler.
+   */
+  void UpdateOutRate(uint32_t aOutRate) {
+    Update(aOutRate, mResampler.GetChannels());
+  }
+
+  /**
+   * Set the duration that should be used for pre-buffering.
+   */
+  void SetPreBufferDuration(media::TimeUnit aPreBufferDuration) {
+    mResampler.SetPreBufferDuration(aPreBufferDuration);
+  }
+
+ private:
+  void UpdateChannels(uint32_t aChannels) {
+    Update(mResampler.GetOutRate(), aChannels);
+  }
+  void Update(uint32_t aOutRate, uint32_t aChannels);
+
+ private:
+  DynamicResampler mResampler;
+  AudioChunkList mOutputChunks;
+  bool mIsSampleFormatSet = false;
+};
+
+}  // namespace mozilla
+
+#endif  // DOM_MEDIA_DRIFTCONTROL_AUDIORESAMPLER_H_