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/*
* This file is part of Shairport Sync.
* Copyright (c) Mike Brady 2019
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <string.h>
// these are headers for the ALAC decoder, utilities and endian utilities
#include <alac/ALACBitUtilities.h>
#include <alac/ALACDecoder.h>
#include <alac/EndianPortable.h>
#include "apple_alac.h"
#include "config.h"
typedef struct magicCookie {
ALACSpecificConfig config;
ALACAudioChannelLayout channelLayoutInfo; // seems to be unused
} magicCookie;
magicCookie cookie;
ALACDecoder *theDecoder;
extern "C" int apple_alac_init(int32_t fmtp[12]) {
memset(&cookie, 0, sizeof(magicCookie));
// create a magic cookie for the decoder from the fmtp information. It seems to be in the same
// format as a simple magic cookie
cookie.config.frameLength = Swap32NtoB(352);
cookie.config.compatibleVersion = fmtp[2]; // should be zero, uint8_t
cookie.config.bitDepth = fmtp[3]; // uint8_t expected to be 16
cookie.config.pb = fmtp[4]; // uint8_t should be 40;
cookie.config.mb = fmtp[5]; // uint8_t should be 10;
cookie.config.kb = fmtp[6]; // uint8_t should be 14;
cookie.config.numChannels = fmtp[7]; // uint8_t expected to be 2
cookie.config.maxRun = Swap16NtoB(fmtp[8]); // uint16_t expected to be 255
cookie.config.maxFrameBytes = Swap32NtoB(fmtp[9]); // uint32_t should be 0;
cookie.config.avgBitRate = Swap32NtoB(fmtp[10]); // uint32_t should be 0;;
cookie.config.sampleRate = Swap32NtoB(fmtp[11]); // uint32_t expected to be 44100;
theDecoder = new ALACDecoder;
theDecoder->Init(&cookie, sizeof(magicCookie));
return 0;
}
extern "C" int apple_alac_decode_frame(unsigned char *sampleBuffer, uint32_t bufferLength,
unsigned char *dest, int *outsize) {
uint32_t numFrames = 0;
BitBuffer theInputBuffer;
BitBufferInit(&theInputBuffer, sampleBuffer, bufferLength);
theDecoder->Decode(&theInputBuffer, dest, Swap32BtoN(cookie.config.frameLength),
cookie.config.numChannels, &numFrames);
*outsize = numFrames;
return 0;
}
extern "C" int apple_alac_terminate() {
delete (theDecoder);
return 0;
}
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