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 namespace android {
20 
21 inline constexpr uint32_t kSpdifEncodedChannelCount = 2u;
22 inline constexpr uint32_t kSpdifDataTypeAc3 = 1u;
23 inline constexpr uint32_t kSpdifDataTypeEac3 = 21u;
24 inline constexpr uint32_t kSpdifRateMultiplierEac3 = 4u;
25 
26 // Burst preamble defined in IEC61937-1
27 inline constexpr uint16_t kSpdifSync1 = 0xF872;  // Pa
28 inline constexpr uint16_t kSpdifSync2 = 0x4E1F;  // Pb
29 
30 // Returns the SPDIF rate multiplier for the audio format, or zero if not supported.
spdif_rate_multiplier(audio_format_t format)31 inline int spdif_rate_multiplier(audio_format_t format) {
32     switch (format) {
33         case AUDIO_FORMAT_E_AC3:
34         case AUDIO_FORMAT_E_AC3_JOC:
35             return 4;
36         case AUDIO_FORMAT_AC3:
37         case AUDIO_FORMAT_DTS:
38         case AUDIO_FORMAT_DTS_HD:
39             return 1;
40         default:
41             return 0;
42     }
43 }
44 
45 }  // namespace android
46