1 /* 2 * Copyright (C) 2018 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 package org.mozilla.thirdparty.com.google.android.exoplayer2.audio; 17 18 import org.mozilla.thirdparty.com.google.android.exoplayer2.C; 19 import org.mozilla.thirdparty.com.google.android.exoplayer2.Format; 20 import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util; 21 22 /** Utilities for handling WAVE files. */ 23 public final class WavUtil { 24 25 /** Four character code for "RIFF". */ 26 public static final int RIFF_FOURCC = 0x52494646; 27 /** Four character code for "WAVE". */ 28 public static final int WAVE_FOURCC = 0x57415645; 29 /** Four character code for "fmt ". */ 30 public static final int FMT_FOURCC = 0x666d7420; 31 /** Four character code for "data". */ 32 public static final int DATA_FOURCC = 0x64617461; 33 34 /** WAVE type value for integer PCM audio data. */ 35 public static final int TYPE_PCM = 0x0001; 36 /** WAVE type value for float PCM audio data. */ 37 public static final int TYPE_FLOAT = 0x0003; 38 /** WAVE type value for 8-bit ITU-T G.711 A-law audio data. */ 39 public static final int TYPE_ALAW = 0x0006; 40 /** WAVE type value for 8-bit ITU-T G.711 mu-law audio data. */ 41 public static final int TYPE_MLAW = 0x0007; 42 /** WAVE type value for IMA ADPCM audio data. */ 43 public static final int TYPE_IMA_ADPCM = 0x0011; 44 /** WAVE type value for extended WAVE format. */ 45 public static final int TYPE_WAVE_FORMAT_EXTENSIBLE = 0xFFFE; 46 47 /** 48 * Returns the WAVE format type value for the given {@link C.PcmEncoding}. 49 * 50 * @param pcmEncoding The {@link C.PcmEncoding} value. 51 * @return The corresponding WAVE format type. 52 * @throws IllegalArgumentException If {@code pcmEncoding} is not a {@link C.PcmEncoding}, or if 53 * it's {@link C#ENCODING_INVALID} or {@link Format#NO_VALUE}. 54 */ getTypeForPcmEncoding(@.PcmEncoding int pcmEncoding)55 public static int getTypeForPcmEncoding(@C.PcmEncoding int pcmEncoding) { 56 switch (pcmEncoding) { 57 case C.ENCODING_PCM_8BIT: 58 case C.ENCODING_PCM_16BIT: 59 case C.ENCODING_PCM_24BIT: 60 case C.ENCODING_PCM_32BIT: 61 return TYPE_PCM; 62 case C.ENCODING_PCM_FLOAT: 63 return TYPE_FLOAT; 64 case C.ENCODING_PCM_16BIT_BIG_ENDIAN: // Not TYPE_PCM, because TYPE_PCM is little endian. 65 case C.ENCODING_INVALID: 66 case Format.NO_VALUE: 67 default: 68 throw new IllegalArgumentException(); 69 } 70 } 71 72 /** 73 * Returns the {@link C.PcmEncoding} for the given WAVE format type value, or {@link 74 * C#ENCODING_INVALID} if the type is not a known PCM type. 75 */ getPcmEncodingForType(int type, int bitsPerSample)76 public static @C.PcmEncoding int getPcmEncodingForType(int type, int bitsPerSample) { 77 switch (type) { 78 case TYPE_PCM: 79 case TYPE_WAVE_FORMAT_EXTENSIBLE: 80 return Util.getPcmEncoding(bitsPerSample); 81 case TYPE_FLOAT: 82 return bitsPerSample == 32 ? C.ENCODING_PCM_FLOAT : C.ENCODING_INVALID; 83 default: 84 return C.ENCODING_INVALID; 85 } 86 } 87 WavUtil()88 private WavUtil() { 89 // Prevent instantiation. 90 } 91 } 92