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