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82 lines
3.0 KiB
82 lines
3.0 KiB
/*
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* Copyright 2014, The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_AUDIO_AC3_FRAME_SCANNER_H
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#define ANDROID_AUDIO_AC3_FRAME_SCANNER_H
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#include <stdint.h>
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#include <system/audio.h>
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#include <audio_utils/spdif/FrameScanner.h>
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namespace android {
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#define AC3_NUM_SAMPLE_RATE_TABLE_ENTRIES 3
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#define AC3_NUM_FRAME_SIZE_TABLE_ENTRIES 38
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#define AC3_PCM_FRAMES_PER_BLOCK 256
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#define AC3_MAX_BLOCKS_PER_SYNC_FRAME_BLOCK 6
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#define EAC3_RATE_MULTIPLIER 4
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#define EAC3_NUM_SAMPLE_RATE_TABLE_ENTRIES 3
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#define EAC3_NUM_BLOCKS_PER_FRAME_TABLE_ENTRIES 38
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#define EAC3_MAX_SUBSTREAMS 8
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class AC3FrameScanner : public FrameScanner
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{
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public:
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explicit AC3FrameScanner(audio_format_t format);
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virtual ~AC3FrameScanner();
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virtual int getMaxChannels() const { return 5 + 1; } // 5.1 surround
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virtual int getMaxSampleFramesPerSyncFrame() const { return EAC3_RATE_MULTIPLIER
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* AC3_MAX_BLOCKS_PER_SYNC_FRAME_BLOCK * AC3_PCM_FRAMES_PER_BLOCK; }
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virtual int getSampleFramesPerSyncFrame() const;
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virtual bool isFirstInBurst();
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virtual bool isLastInBurst();
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virtual void resetBurst();
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virtual uint16_t convertBytesToLengthCode(uint16_t numBytes) const;
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protected:
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// Keep track of how many of each substream blocks have been accumulated.
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// We need all of each substream before sending block data burst.
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uint8_t mSubstreamBlockCounts[EAC3_MAX_SUBSTREAMS];
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int mAudioBlocksPerSyncFrame;
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// The type of EAC3 stream as per EAC3 spec paragraph 2.3.1.1
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uint32_t mStreamType;
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// substream index
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uint32_t mSubstreamID;
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audio_format_t mFormat;
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// used to recognize the start of an AC3 sync frame
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static const uint8_t kSyncBytes[];
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// sample rates from AC3 spec table 5.1
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static const uint16_t kAC3SampleRateTable[AC3_NUM_SAMPLE_RATE_TABLE_ENTRIES];
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// frame sizes from AC3 spec table 5.13
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static const uint16_t kAC3FrameSizeTable[AC3_NUM_FRAME_SIZE_TABLE_ENTRIES]
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[AC3_NUM_SAMPLE_RATE_TABLE_ENTRIES];
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// sample rates from EAC3 spec table E2.3
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static const uint16_t kEAC3ReducedSampleRateTable[AC3_NUM_SAMPLE_RATE_TABLE_ENTRIES];
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// audio blocks per frame from EAC3 spec table E2.4
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static const uint16_t kEAC3BlocksPerFrameTable[EAC3_NUM_BLOCKS_PER_FRAME_TABLE_ENTRIES];
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virtual bool parseHeader();
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};
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} // namespace android
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#endif // ANDROID_AUDIO_AC3_FRAME_SCANNER_H
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