1 /*
2  * Copyright 2023, The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #pragma once
18 
19 #include <stdint.h>
20 #include <system/audio.h>
21 #include <audio_utils/spdif/FrameScanner.h>
22 #include <audio_utils/spdif/SPDIF.h>
23 
24 namespace android {
25 
26 inline constexpr uint32_t kEac3PcmFramesPerBlock = 256u;
27 inline constexpr uint32_t kEac3MaxBlocksPerSyncFrame = 6u;
28 
29 // Scanner for IEC61937 streams.
30 class SPDIFFrameScanner : public FrameScanner {
31  public:
32     explicit SPDIFFrameScanner(audio_format_t format);
33 
getMaxChannels()34     virtual int getMaxChannels() const { return kSpdifEncodedChannelCount; }  // IEC61937
35 
getMaxSampleFramesPerSyncFrame()36     virtual int getMaxSampleFramesPerSyncFrame() const {
37         return kSpdifRateMultiplierEac3 * kEac3MaxBlocksPerSyncFrame
38                 * kEac3PcmFramesPerBlock;
39     }
40 
getSampleFramesPerSyncFrame()41     virtual int getSampleFramesPerSyncFrame() const {
42         return mRateMultiplier * kEac3MaxBlocksPerSyncFrame * kEac3PcmFramesPerBlock;
43     }
44 
isFirstInBurst()45     virtual bool isFirstInBurst() { return true; }
isLastInBurst()46     virtual bool isLastInBurst() { return true; }
resetBurst()47     virtual void resetBurst() { }
48 
49  protected:
50     // used to recognize the start of an IEC61937 frame
51     static const uint8_t kSyncBytes[];
52 
53     virtual bool parseHeader();
54 };
55 
56 }  // namespace android
57