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+/* -*- 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 OpusTrackEncoder_h_
+#define OpusTrackEncoder_h_
+
+#include <stdint.h>
+#include <speex/speex_resampler.h>
+#include "TimeUnits.h"
+#include "TrackEncoder.h"
+
+struct OpusEncoder;
+
+namespace mozilla {
+
+// Opus meta data structure
+class OpusMetadata : public TrackMetadataBase {
+ public:
+ // The ID Header of OggOpus. refer to http://wiki.xiph.org/OggOpus.
+ nsTArray<uint8_t> mIdHeader;
+ // The Comment Header of OggOpus.
+ nsTArray<uint8_t> mCommentHeader;
+ int32_t mChannels;
+ float mSamplingFrequency;
+ MetadataKind GetKind() const override { return METADATA_OPUS; }
+};
+
+class OpusTrackEncoder : public AudioTrackEncoder {
+ public:
+ OpusTrackEncoder(TrackRate aTrackRate,
+ MediaQueue<EncodedFrame>& aEncodedDataQueue);
+ virtual ~OpusTrackEncoder();
+
+ already_AddRefed<TrackMetadataBase> GetMetadata() override;
+
+ /**
+ * The encoder lookahead at 48k rate.
+ */
+ int GetLookahead() const;
+
+ protected:
+ /**
+ * The number of frames, in the input rate mTrackRate, needed to fill an
+ * encoded opus packet. A frame is a sample per channel.
+ */
+ int NumInputFramesPerPacket() const override;
+
+ nsresult Init(int aChannels) override;
+
+ /**
+ * Encodes buffered data and pushes it to mEncodedDataQueue.
+ */
+ nsresult Encode(AudioSegment* aSegment) override;
+
+ /**
+ * The number of frames, in the output rate (see GetOutputSampleRate), needed
+ * to fill an encoded opus packet. A frame is a sample per channel.
+ */
+ int NumOutputFramesPerPacket() const;
+
+ /**
+ * True if the input needs to be resampled to be fed to the underlying opus
+ * encoder.
+ */
+ bool NeedsResampler() const;
+
+ public:
+ /**
+ * Get the samplerate of the data to be fed to the Opus encoder. This might be
+ * different from the input samplerate if resampling occurs.
+ */
+ const TrackRate mOutputSampleRate;
+
+ private:
+ /**
+ * The Opus encoder from libopus.
+ */
+ OpusEncoder* mEncoder;
+
+ /**
+ * Total samples of delay added by codec (in rate mOutputSampleRate), can
+ * be queried by the encoder. From the perspective of decoding, real data
+ * begins this many samples late, so the encoder needs to append this many
+ * null samples to the end of stream, in order to align the time of input and
+ * output.
+ */
+ int mLookahead;
+
+ /**
+ * Number of mLookahead samples that has been written. When non-zero and equal
+ * to mLookahead, encoding is complete.
+ */
+ int mLookaheadWritten;
+
+ /**
+ * If the input sample rate does not divide 48kHz evenly, the input data are
+ * resampled.
+ */
+ SpeexResamplerState* mResampler;
+
+ /**
+ * Store the resampled frames that don't fit into an Opus packet duration.
+ * They will be prepended to the resampled frames next encoding cycle.
+ */
+ nsTArray<AudioDataValue> mResampledLeftover;
+
+ /**
+ * Number of audio frames encoded, in kOpusSamplingRate.
+ */
+ uint64_t mNumOutputFrames;
+};
+
+} // namespace mozilla
+
+#endif