Mike Brady
60143518c2
- 48,000 frames per second operation, - 48k lossless stereo, 5.1 and 7.1 surround sound - Multichannel and multi rate operation on ALSA, PipeWire, PulseAudio, FreeBSD, stdout and unix pipe output backends. Automatic, flexible and controllable output format (rate, sample format and channel count) selection. Full FFmpeg integration to support transcoding, resampling, and new audio formats. Better operation on lower powered devices down to e.g. Raspberry Pi B. Reduced Docker image sizes with a slimmed-down FFmpeg library. Enhanced timestamp handling for better synchronization. Improved the sync error calculation. A new "vernier" resampling and interpolation method for low-power CPUs. Bug fixes and minor enhancements. Note -- there are many breaking changes from previous versions of Shairport Sync!
85 lines
3.3 KiB
C++
85 lines
3.3 KiB
C++
/*
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* This file is part of Shairport Sync.
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* Copyright (c) Mike Brady 2019--2025
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* All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <string.h>
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// these are headers for the ALAC decoder, utilities and endian utilities
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#include <alac/ALACBitUtilities.h>
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#include <alac/ALACDecoder.h>
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#include <alac/EndianPortable.h>
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#include "apple_alac.h"
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#include "config.h"
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typedef struct magicCookie {
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ALACSpecificConfig config;
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ALACAudioChannelLayout channelLayoutInfo; // seems to be unused
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} magicCookie;
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magicCookie cookie;
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ALACDecoder *theDecoder;
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extern "C" int apple_alac_init(int32_t fmtp[12]) {
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memset(&cookie, 0, sizeof(magicCookie));
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// create a magic cookie for the decoder from the fmtp information. It seems to be in the same
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// format as a simple magic cookie
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cookie.config.frameLength = Swap32NtoB(352);
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cookie.config.compatibleVersion = fmtp[2]; // should be zero, uint8_t
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cookie.config.bitDepth = fmtp[3]; // uint8_t expected to be 16
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cookie.config.pb = fmtp[4]; // uint8_t should be 40;
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cookie.config.mb = fmtp[5]; // uint8_t should be 10;
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cookie.config.kb = fmtp[6]; // uint8_t should be 14;
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cookie.config.numChannels = fmtp[7]; // uint8_t expected to be 2
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cookie.config.maxRun = Swap16NtoB(fmtp[8]); // uint16_t expected to be 255
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cookie.config.maxFrameBytes = Swap32NtoB(fmtp[9]); // uint32_t should be 0;
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cookie.config.avgBitRate = Swap32NtoB(fmtp[10]); // uint32_t should be 0;;
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cookie.config.sampleRate = Swap32NtoB(fmtp[11]); // uint32_t expected to be 44100;
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theDecoder = new ALACDecoder;
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theDecoder->Init(&cookie, sizeof(magicCookie));
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return 0;
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}
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extern "C" int apple_alac_decode_frame(unsigned char *sampleBuffer, uint32_t bufferLength,
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unsigned char *dest, int *outsize) {
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uint32_t numFrames = 0;
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BitBuffer theInputBuffer;
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BitBufferInit(&theInputBuffer, sampleBuffer, bufferLength);
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theDecoder->Decode(&theInputBuffer, dest, Swap32BtoN(cookie.config.frameLength),
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cookie.config.numChannels, &numFrames);
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*outsize = numFrames;
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return 0;
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}
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extern "C" int apple_alac_terminate() {
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delete (theDecoder);
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return 0;
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}
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