Audio Queue Services 参考示例

/* File: CAStreamBasicDescription.cpp Abstract: Helper class for audio stream descriptions Version: 2.4 Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc. ("Apple") in consideration of your agreement to the following terms, and your use, installation, modification or redistribution of this Apple software constitutes acceptance of these terms. If you do not agree with these terms, please do not use, install, modify or redistribute this Apple software. 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All Rights Reserved. */ #include "CAStreamBasicDescription.h" #include "CAMath.h" #if !defined(__COREAUDIO_USE_FLAT_INCLUDES__) #include <CoreFoundation/CFByteOrder.h> #else #include <CFByteOrder.h> #endif #if TARGET_OS_WIN32 #include <stddef.h> #endif #pragma mark This file needs to compile on earlier versions of the OS, so please keep that in mind when editing it const AudioStreamBasicDescription CAStreamBasicDescription::sEmpty = { 0.0, 0, 0, 0, 0, 0, 0, 0, 0 }; CAStreamBasicDescription::CAStreamBasicDescription(double inSampleRate, UInt32 inFormatID, UInt32 inBytesPerPacket, UInt32 inFramesPerPacket, UInt32 inBytesPerFrame, UInt32 inChannelsPerFrame, UInt32 inBitsPerChannel, UInt32 inFormatFlags) { mSampleRate = inSampleRate; mFormatID = inFormatID; mBytesPerPacket = inBytesPerPacket; mFramesPerPacket = inFramesPerPacket; mBytesPerFrame = inBytesPerFrame; mChannelsPerFrame = inChannelsPerFrame; mBitsPerChannel = inBitsPerChannel; mFormatFlags = inFormatFlags; mReserved = 0; } char *CAStreamBasicDescription::AsString(char *buf, size_t bufsize) const { char *theBuffer = buf; int nc; char formatID[5]; *(UInt32 *)formatID = CFSwapInt32HostToBig(mFormatID); formatID[4] = '\0'; nc = snprintf(buf, bufsize, "%2d ch, %6.0f Hz, '%-4.4s' (0x%08X) ", (int)NumberChannels(), mSampleRate, formatID, (int)mFormatFlags); buf += nc; bufsize -= nc; if (mFormatID == kAudioFormatLinearPCM) { bool isInt = !(mFormatFlags & kLinearPCMFormatFlagIsFloat); int wordSize = SampleWordSize(); const char *endian = (wordSize > 1) ? ((mFormatFlags & kLinearPCMFormatFlagIsBigEndian) ? " big-endian" : " little-endian" ) : ""; const char *sign = isInt ? ((mFormatFlags & kLinearPCMFormatFlagIsSignedInteger) ? " signed" : " unsigned") : ""; const char *floatInt = isInt ? "integer" : "float"; char packed[32]; if (wordSize > 0 && PackednessIsSignificant()) { if (mFormatFlags & kLinearPCMFormatFlagIsPacked) sprintf(packed, "packed in %d bytes", wordSize); else sprintf(packed, "unpacked in %d bytes", wordSize); } else packed[0] = '\0'; const char *align = (wordSize > 0 && AlignmentIsSignificant()) ? ((mFormatFlags & kLinearPCMFormatFlagIsAlignedHigh) ? " high-aligned" : " low-aligned") : ""; const char *deinter = (mFormatFlags & kAudioFormatFlagIsNonInterleaved) ? ", deinterleaved" : ""; const char *commaSpace = (packed[0]!='\0') || (align[0]!='\0') ? ", " : ""; char bitdepth[20]; #if CA_PREFER_FIXED_POINT int fracbits = (mFormatFlags & kLinearPCMFormatFlagsSampleFractionMask) >> kLinearPCMFormatFlagsSampleFractionShift; if (fracbits > 0) sprintf(bitdepth, "%d.%d", (int)mBitsPerChannel - fracbits, fracbits); else #endif sprintf(bitdepth, "%d", (int)mBitsPerChannel); nc = snprintf(buf, bufsize, "%s-bit%s%s %s%s%s%s%s", bitdepth, endian, sign, floatInt, commaSpace, packed, align, deinter); //buf += nc; bufsize -= nc; } else if (mFormatID == 'alac') { // kAudioFormatAppleLossless int sourceBits = 0; switch (mFormatFlags) { case 1: // kAppleLosslessFormatFlag_16BitSourceData sourceBits = 16; break; case 2: // kAppleLosslessFormatFlag_20BitSourceData sourceBits = 20; break; case 3: // kAppleLosslessFormatFlag_24BitSourceData sourceBits = 24; break; case 4: // kAppleLosslessFormatFlag_32BitSourceData sourceBits = 32; break; } if (sourceBits) nc = snprintf(buf, bufsize, "from %d-bit source, ", sourceBits); else nc = snprintf(buf, bufsize, "from UNKNOWN source bit depth, "); buf += nc; bufsize -= nc; nc = snprintf(buf, bufsize, "%d frames/packet", (int)mFramesPerPacket); //buf += nc; bufsize -= nc; } else nc = snprintf(buf, bufsize, "%d bits/channel, %d bytes/packet, %d frames/packet, %d bytes/frame", (int)mBitsPerChannel, (int)mBytesPerPacket, (int)mFramesPerPacket, (int)mBytesPerFrame); return theBuffer; } void CAStreamBasicDescription::NormalizeLinearPCMFormat(AudioStreamBasicDescription& ioDescription) { // the only thing that changes is to make mixable linear PCM into the canonical linear PCM format if((ioDescription.mFormatID == kAudioFormatLinearPCM) && ((ioDescription.mFormatFlags & kIsNonMixableFlag) == 0)) { // the canonical linear PCM format ioDescription.mFormatFlags = kAudioFormatFlagsCanonical; ioDescription.mBytesPerPacket = sizeof(AudioSampleType) * ioDescription.mChannelsPerFrame; ioDescription.mFramesPerPacket = 1; ioDescription.mBytesPerFrame = sizeof(AudioSampleType) * ioDescription.mChannelsPerFrame; ioDescription.mBitsPerChannel = 8 * sizeof(AudioSampleType); } } void CAStreamBasicDescription::ResetFormat(AudioStreamBasicDescription& ioDescription) { ioDescription.mSampleRate = 0; ioDescription.mFormatID = 0; ioDescription.mBytesPerPacket = 0; ioDescription.mFramesPerPacket = 0; ioDescription.mBytesPerFrame = 0; ioDescription.mChannelsPerFrame = 0; ioDescription.mBitsPerChannel = 0; ioDescription.mFormatFlags = 0; } void CAStreamBasicDescription::FillOutFormat(AudioStreamBasicDescription& ioDescription, const AudioStreamBasicDescription& inTemplateDescription) { if(fiszero(ioDescription.mSampleRate)) { ioDescription.mSampleRate = inTemplateDescription.mSampleRate; } if(ioDescription.mFormatID == 0) { ioDescription.mFormatID = inTemplateDescription.mFormatID; } if(ioDescription.mFormatFlags == 0) { ioDescription.mFormatFlags = inTemplateDescription.mFormatFlags; } if(ioDescription.mBytesPerPacket == 0) { ioDescription.m