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81 lines
3.0 KiB
81 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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