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- /*
- * ALAC (Apple Lossless Audio Codec) decoder
- * Copyright (c) 2005 David Hammerton
- * All rights reserved.
- *
- * This is the actual decoder.
- *
- * http://crazney.net/programs/itunes/alac.html
- *
- * 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.
- *
- */
- #if (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
- static const int host_bigendian = 0;
- #else
- static const int host_bigendian = 1;
- #endif
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <stdint.h>
- #include "alac.h"
- extern int _fprintf(FILE *file, ...);
- #define _Swap32(v) do { \
- v = (((v) & 0x000000FF) << 0x18) | \
- (((v) & 0x0000FF00) << 0x08) | \
- (((v) & 0x00FF0000) >> 0x08) | \
- (((v) & 0xFF000000) >> 0x18); } while(0)
- #define _Swap16(v) do { \
- v = (((v) & 0x00FF) << 0x08) | \
- (((v) & 0xFF00) >> 0x08); } while (0)
- struct {signed int x:24;} se_struct_24;
- #define SignExtend24(val) (se_struct_24.x = val)
- void allocate_buffers(alac_file *alac)
- {
- alac->predicterror_buffer_a = malloc(alac->setinfo_max_samples_per_frame * 4);
- alac->predicterror_buffer_b = malloc(alac->setinfo_max_samples_per_frame * 4);
- alac->outputsamples_buffer_a = malloc(alac->setinfo_max_samples_per_frame * 4);
- alac->outputsamples_buffer_b = malloc(alac->setinfo_max_samples_per_frame * 4);
- alac->uncompressed_bytes_buffer_a = malloc(alac->setinfo_max_samples_per_frame * 4);
- alac->uncompressed_bytes_buffer_b = malloc(alac->setinfo_max_samples_per_frame * 4);
- }
- void alac_set_info(alac_file *alac, char *inputbuffer)
- {
- char *ptr = inputbuffer;
- ptr += 4; /* size */
- ptr += 4; /* frma */
- ptr += 4; /* alac */
- ptr += 4; /* size */
- ptr += 4; /* alac */
- ptr += 4; /* 0 ? */
- alac->setinfo_max_samples_per_frame = *(uint32_t*)ptr; /* buffer size / 2 ? */
- if (!host_bigendian)
- _Swap32(alac->setinfo_max_samples_per_frame);
- ptr += 4;
- alac->setinfo_7a = *(uint8_t*)ptr;
- ptr += 1;
- alac->setinfo_sample_size = *(uint8_t*)ptr;
- ptr += 1;
- alac->setinfo_rice_historymult = *(uint8_t*)ptr;
- ptr += 1;
- alac->setinfo_rice_initialhistory = *(uint8_t*)ptr;
- ptr += 1;
- alac->setinfo_rice_kmodifier = *(uint8_t*)ptr;
- ptr += 1;
- alac->setinfo_7f = *(uint8_t*)ptr;
- ptr += 1;
- alac->setinfo_80 = *(uint16_t*)ptr;
- if (!host_bigendian)
- _Swap16(alac->setinfo_80);
- ptr += 2;
- alac->setinfo_82 = *(uint32_t*)ptr;
- if (!host_bigendian)
- _Swap32(alac->setinfo_82);
- ptr += 4;
- alac->setinfo_86 = *(uint32_t*)ptr;
- if (!host_bigendian)
- _Swap32(alac->setinfo_86);
- ptr += 4;
- alac->setinfo_8a_rate = *(uint32_t*)ptr;
- if (!host_bigendian)
- _Swap32(alac->setinfo_8a_rate);
- allocate_buffers(alac);
- }
- /* stream reading */
- /* supports reading 1 to 16 bits, in big endian format */
- static uint32_t readbits_16(alac_file *alac, int bits)
- {
- uint32_t result;
- int new_accumulator;
- result = (alac->input_buffer[0] << 16) |
- (alac->input_buffer[1] << 8) |
- (alac->input_buffer[2]);
- /* shift left by the number of bits we've already read,
- * so that the top 'n' bits of the 24 bits we read will
- * be the return bits */
- result = result << alac->input_buffer_bitaccumulator;
- result = result & 0x00ffffff;
- /* and then only want the top 'n' bits from that, where
- * n is 'bits' */
- result = result >> (24 - bits);
- new_accumulator = (alac->input_buffer_bitaccumulator + bits);
- /* increase the buffer pointer if we've read over n bytes. */
- alac->input_buffer += (new_accumulator >> 3);
- /* and the remainder goes back into the bit accumulator */
- alac->input_buffer_bitaccumulator = (new_accumulator & 7);
- return result;
- }
- /* supports reading 1 to 32 bits, in big endian format */
- static uint32_t readbits(alac_file *alac, int bits)
- {
- int32_t result = 0;
- if (bits > 16)
- {
- bits -= 16;
- result = readbits_16(alac, 16) << bits;
- }
- result |= readbits_16(alac, bits);
- return result;
- }
- /* reads a single bit */
- static int readbit(alac_file *alac)
- {
- int result;
- int new_accumulator;
- result = alac->input_buffer[0];
- result = result << alac->input_buffer_bitaccumulator;
- result = result >> 7 & 1;
- new_accumulator = (alac->input_buffer_bitaccumulator + 1);
- alac->input_buffer += (new_accumulator / 8);
- alac->input_buffer_bitaccumulator = (new_accumulator % 8);
- return result;
- }
- static void unreadbits(alac_file *alac, int bits)
- {
- int new_accumulator = (alac->input_buffer_bitaccumulator - bits);
- alac->input_buffer += (new_accumulator >> 3);
- alac->input_buffer_bitaccumulator = (new_accumulator & 7);
- if (alac->input_buffer_bitaccumulator < 0)
- alac->input_buffer_bitaccumulator *= -1;
- }
- /* various implementations of count_leading_zero:
- * the first one is the original one, the simplest and most
- * obvious for what it's doing. never use this.
- * then there are the asm ones. fill in as necessary
- * and finally an unrolled and optimised c version
- * to fall back to
- */
- #if 0
- /* hideously inefficient. could use a bitmask search,
- * alternatively bsr on x86,
- */
- static int count_leading_zeros(int32_t input)
- {
- int i = 0;
- while (!(0x80000000 & input) && i < 32)
- {
- i++;
- input = input << 1;
- }
- return i;
- }
- #elif defined(__GNUC__)
- /* for some reason the unrolled version (below) is
- * actually faster than this. yay intel!
- */
- static int count_leading_zeros(int input)
- {
- return __builtin_clz(input);
- }
- #elif (defined(_MSC_VER) || defined (__BORLANDC__)) && defined(_M_IX86)
- static int count_leading_zeros(int input)
- {
- int output = 0;
- if (!input) return 32;
- __asm
- {
- mov eax, input;
- mov edx, 0x1f;
- bsr ecx, eax;
- sub edx, ecx;
- mov output, edx;
- }
- return output;
- }
- #else
- #warning using generic count leading zeroes. You may wish to write one for your CPU / compiler
- static int count_leading_zeros(int input)
- {
- int output = 0;
- int curbyte = 0;
- curbyte = input >> 24;
- if (curbyte) goto found;
- output += 8;
- curbyte = input >> 16;
- if (curbyte & 0xff) goto found;
- output += 8;
- curbyte = input >> 8;
- if (curbyte & 0xff) goto found;
- output += 8;
- curbyte = input;
- if (curbyte & 0xff) goto found;
- output += 8;
- return output;
- found:
- if (!(curbyte & 0xf0))
- {
- output += 4;
- }
- else
- curbyte >>= 4;
- if (curbyte & 0x8)
- return output;
- if (curbyte & 0x4)
- return output + 1;
- if (curbyte & 0x2)
- return output + 2;
- if (curbyte & 0x1)
- return output + 3;
- /* shouldn't get here: */
- return output + 4;
- }
- #endif
- #define RICE_THRESHOLD 8 // maximum number of bits for a rice prefix.
- static int32_t entropy_decode_value(alac_file* alac,
- int readSampleSize,
- int k,
- int rice_kmodifier_mask)
- {
- int32_t x = 0; // decoded value
- // read x, number of 1s before 0 represent the rice value.
- while (x <= RICE_THRESHOLD && readbit(alac))
- {
- x++;
- }
- if (x > RICE_THRESHOLD)
- {
- // read the number from the bit stream (raw value)
- int32_t value;
- value = readbits(alac, readSampleSize);
- // mask value
- value &= (((uint32_t)0xffffffff) >> (32 - readSampleSize));
- x = value;
- }
- else
- {
- if (k != 1)
- {
- int extraBits = readbits(alac, k);
- // x = x * (2^k - 1)
- x *= (((1 << k) - 1) & rice_kmodifier_mask);
- if (extraBits > 1)
- x += extraBits - 1;
- else
- unreadbits(alac, 1);
- }
- }
- return x;
- }
- static void entropy_rice_decode(alac_file* alac,
- int32_t* outputBuffer,
- int outputSize,
- int readSampleSize,
- int rice_initialhistory,
- int rice_kmodifier,
- int rice_historymult,
- int rice_kmodifier_mask)
- {
- int outputCount;
- int history = rice_initialhistory;
- int signModifier = 0;
- for (outputCount = 0; outputCount < outputSize; outputCount++)
- {
- int32_t decodedValue;
- int32_t finalValue;
- int32_t k;
- k = 31 - rice_kmodifier - count_leading_zeros((history >> 9) + 3);
- if (k < 0) k += rice_kmodifier;
- else k = rice_kmodifier;
- // note: don't use rice_kmodifier_mask here (set mask to 0xFFFFFFFF)
- decodedValue = entropy_decode_value(alac, readSampleSize, k, 0xFFFFFFFF);
- decodedValue += signModifier;
- finalValue = (decodedValue + 1) / 2; // inc by 1 and shift out sign bit
- if (decodedValue & 1) // the sign is stored in the low bit
- finalValue *= -1;
- outputBuffer[outputCount] = finalValue;
- signModifier = 0;
- // update history
- history += (decodedValue * rice_historymult)
- - ((history * rice_historymult) >> 9);
- if (decodedValue > 0xFFFF)
- history = 0xFFFF;
- // special case, for compressed blocks of 0
- if ((history < 128) && (outputCount + 1 < outputSize))
- {
- int32_t blockSize;
- signModifier = 1;
- k = count_leading_zeros(history) + ((history + 16) / 64) - 24;
- // note: blockSize is always 16bit
- blockSize = entropy_decode_value(alac, 16, k, rice_kmodifier_mask);
- // got blockSize 0s
- if (blockSize > 0)
- {
- memset(&outputBuffer[outputCount + 1], 0, blockSize * sizeof(*outputBuffer));
- outputCount += blockSize;
- }
- if (blockSize > 0xFFFF)
- signModifier = 0;
- history = 0;
- }
- }
- }
- #define SIGN_EXTENDED32(val, bits) ((val << (32 - bits)) >> (32 - bits))
- #define SIGN_ONLY(v) \
- ((v < 0) ? (-1) : \
- ((v > 0) ? (1) : \
- (0)))
- static void predictor_decompress_fir_adapt(int32_t *error_buffer,
- int32_t *buffer_out,
- int output_size,
- int readsamplesize,
- int16_t *predictor_coef_table,
- int predictor_coef_num,
- int predictor_quantitization)
- {
- int i;
- /* first sample always copies */
- *buffer_out = *error_buffer;
- if (!predictor_coef_num)
- {
- if (output_size <= 1) return;
- memcpy(buffer_out+1, error_buffer+1, (output_size-1) * 4);
- return;
- }
- if (predictor_coef_num == 0x1f) /* 11111 - max value of predictor_coef_num */
- { /* second-best case scenario for fir decompression,
- * error describes a small difference from the previous sample only
- */
- if (output_size <= 1) return;
- for (i = 0; i < output_size - 1; i++)
- {
- int32_t prev_value;
- int32_t error_value;
- prev_value = buffer_out[i];
- error_value = error_buffer[i+1];
- buffer_out[i+1] = SIGN_EXTENDED32((prev_value + error_value), readsamplesize);
- }
- return;
- }
- /* read warm-up samples */
- if (predictor_coef_num > 0)
- {
- int i;
- for (i = 0; i < predictor_coef_num; i++)
- {
- int32_t val;
- val = buffer_out[i] + error_buffer[i+1];
- val = SIGN_EXTENDED32(val, readsamplesize);
- buffer_out[i+1] = val;
- }
- }
- #if 0
- /* 4 and 8 are very common cases (the only ones i've seen). these
- * should be unrolled and optimised
- */
- if (predictor_coef_num == 4)
- {
- /* FIXME: optimised general case */
- return;
- }
- if (predictor_coef_table == 8)
- {
- /* FIXME: optimised general case */
- return;
- }
- #endif
- /* general case */
- if (predictor_coef_num > 0)
- {
- for (i = predictor_coef_num + 1;
- i < output_size;
- i++)
- {
- int j;
- int sum = 0;
- int outval;
- int error_val = error_buffer[i];
- for (j = 0; j < predictor_coef_num; j++)
- {
- sum += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
- predictor_coef_table[j];
- }
- outval = (1 << (predictor_quantitization-1)) + sum;
- outval = outval >> predictor_quantitization;
- outval = outval + buffer_out[0] + error_val;
- outval = SIGN_EXTENDED32(outval, readsamplesize);
- buffer_out[predictor_coef_num+1] = outval;
- if (error_val > 0)
- {
- int predictor_num = predictor_coef_num - 1;
- while (predictor_num >= 0 && error_val > 0)
- {
- int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
- int sign = SIGN_ONLY(val);
- predictor_coef_table[predictor_num] -= sign;
- val *= sign; /* absolute value */
- error_val -= ((val >> predictor_quantitization) *
- (predictor_coef_num - predictor_num));
- predictor_num--;
- }
- }
- else if (error_val < 0)
- {
- int predictor_num = predictor_coef_num - 1;
- while (predictor_num >= 0 && error_val < 0)
- {
- int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
- int sign = - SIGN_ONLY(val);
- predictor_coef_table[predictor_num] -= sign;
- val *= sign; /* neg value */
- error_val -= ((val >> predictor_quantitization) *
- (predictor_coef_num - predictor_num));
- predictor_num--;
- }
- }
- buffer_out++;
- }
- }
- }
- static void deinterlace_16(int32_t *buffer_a, int32_t *buffer_b,
- int16_t *buffer_out,
- int numchannels, int numsamples,
- uint8_t interlacing_shift,
- uint8_t interlacing_leftweight)
- {
- int i;
- if (numsamples <= 0) return;
- /* weighted interlacing */
- if (interlacing_leftweight)
- {
- for (i = 0; i < numsamples; i++)
- {
- int32_t difference, midright;
- int16_t left;
- int16_t right;
- midright = buffer_a[i];
- difference = buffer_b[i];
- right = midright - ((difference * interlacing_leftweight) >> interlacing_shift);
- left = right + difference;
- /* output is always little endian */
- if (host_bigendian)
- {
- _Swap16(left);
- _Swap16(right);
- }
- buffer_out[i*numchannels] = left;
- buffer_out[i*numchannels + 1] = right;
- }
- return;
- }
- /* otherwise basic interlacing took place */
- for (i = 0; i < numsamples; i++)
- {
- int16_t left, right;
- left = buffer_a[i];
- right = buffer_b[i];
- /* output is always little endian */
- if (host_bigendian)
- {
- _Swap16(left);
- _Swap16(right);
- }
- buffer_out[i*numchannels] = left;
- buffer_out[i*numchannels + 1] = right;
- }
- }
- static void deinterlace_24(int32_t *buffer_a, int32_t *buffer_b,
- int uncompressed_bytes,
- int32_t *uncompressed_bytes_buffer_a, int32_t *uncompressed_bytes_buffer_b,
- void *buffer_out,
- int numchannels, int numsamples,
- uint8_t interlacing_shift,
- uint8_t interlacing_leftweight)
- {
- int i;
- if (numsamples <= 0) return;
- /* weighted interlacing */
- if (interlacing_leftweight)
- {
- for (i = 0; i < numsamples; i++)
- {
- int32_t difference, midright;
- int32_t left;
- int32_t right;
- midright = buffer_a[i];
- difference = buffer_b[i];
- right = midright - ((difference * interlacing_leftweight) >> interlacing_shift);
- left = right + difference;
- if (uncompressed_bytes)
- {
- uint32_t mask = ~(0xFFFFFFFF << (uncompressed_bytes * 8));
- left <<= (uncompressed_bytes * 8);
- right <<= (uncompressed_bytes * 8);
- left |= uncompressed_bytes_buffer_a[i] & mask;
- right |= uncompressed_bytes_buffer_b[i] & mask;
- }
- ((uint8_t*)buffer_out)[i * numchannels * 3] = (left) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 1] = (left >> 8) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 2] = (left >> 16) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 3] = (right) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 4] = (right >> 8) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 5] = (right >> 16) & 0xFF;
- }
- return;
- }
- /* otherwise basic interlacing took place */
- for (i = 0; i < numsamples; i++)
- {
- int32_t left, right;
- left = buffer_a[i];
- right = buffer_b[i];
- if (uncompressed_bytes)
- {
- uint32_t mask = ~(0xFFFFFFFF << (uncompressed_bytes * 8));
- left <<= (uncompressed_bytes * 8);
- right <<= (uncompressed_bytes * 8);
- left |= uncompressed_bytes_buffer_a[i] & mask;
- right |= uncompressed_bytes_buffer_b[i] & mask;
- }
- ((uint8_t*)buffer_out)[i * numchannels * 3] = (left) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 1] = (left >> 8) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 2] = (left >> 16) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 3] = (right) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 4] = (right >> 8) & 0xFF;
- ((uint8_t*)buffer_out)[i * numchannels * 3 + 5] = (right >> 16) & 0xFF;
- }
- }
- void decode_frame(alac_file *alac,
- unsigned char *inbuffer,
- void *outbuffer, int *outputsize)
- {
- int channels;
- int32_t outputsamples = alac->setinfo_max_samples_per_frame;
- /* setup the stream */
- alac->input_buffer = inbuffer;
- alac->input_buffer_bitaccumulator = 0;
- channels = readbits(alac, 3);
- *outputsize = outputsamples * alac->bytespersample;
- switch(channels)
- {
- case 0: /* 1 channel */
- {
- int hassize;
- int isnotcompressed;
- int readsamplesize;
- int uncompressed_bytes;
- int ricemodifier;
- /* 2^result = something to do with output waiting.
- * perhaps matters if we read > 1 frame in a pass?
- */
- readbits(alac, 4);
- readbits(alac, 12); /* unknown, skip 12 bits */
- hassize = readbits(alac, 1); /* the output sample size is stored soon */
- uncompressed_bytes = readbits(alac, 2); /* number of bytes in the (compressed) stream that are not compressed */
- isnotcompressed = readbits(alac, 1); /* whether the frame is compressed */
- if (hassize)
- {
- /* now read the number of samples,
- * as a 32bit integer */
- outputsamples = readbits(alac, 32);
- *outputsize = outputsamples * alac->bytespersample;
- }
- readsamplesize = alac->setinfo_sample_size - (uncompressed_bytes * 8);
- if (!isnotcompressed)
- { /* so it is compressed */
- int16_t predictor_coef_table[32];
- int predictor_coef_num;
- int prediction_type;
- int prediction_quantitization;
- int i;
- /* skip 16 bits, not sure what they are. seem to be used in
- * two channel case */
- readbits(alac, 8);
- readbits(alac, 8);
- prediction_type = readbits(alac, 4);
- prediction_quantitization = readbits(alac, 4);
- ricemodifier = readbits(alac, 3);
- predictor_coef_num = readbits(alac, 5);
- /* read the predictor table */
- for (i = 0; i < predictor_coef_num; i++)
- {
- predictor_coef_table[i] = (int16_t)readbits(alac, 16);
- }
- if (uncompressed_bytes)
- {
- int i;
- for (i = 0; i < outputsamples; i++)
- {
- alac->uncompressed_bytes_buffer_a[i] = readbits(alac, uncompressed_bytes * 8);
- }
- }
- entropy_rice_decode(alac,
- alac->predicterror_buffer_a,
- outputsamples,
- readsamplesize,
- alac->setinfo_rice_initialhistory,
- alac->setinfo_rice_kmodifier,
- ricemodifier * alac->setinfo_rice_historymult / 4,
- (1 << alac->setinfo_rice_kmodifier) - 1);
- if (prediction_type == 0)
- { /* adaptive fir */
- predictor_decompress_fir_adapt(alac->predicterror_buffer_a,
- alac->outputsamples_buffer_a,
- outputsamples,
- readsamplesize,
- predictor_coef_table,
- predictor_coef_num,
- prediction_quantitization);
- }
- else
- {
- _fprintf(stderr, "FIXME: unhandled predicition type: %i\n", prediction_type);
- /* i think the only other prediction type (or perhaps this is just a
- * boolean?) runs adaptive fir twice.. like:
- * predictor_decompress_fir_adapt(predictor_error, tempout, ...)
- * predictor_decompress_fir_adapt(predictor_error, outputsamples ...)
- * little strange..
- */
- }
- }
- else
- { /* not compressed, easy case */
- if (alac->setinfo_sample_size <= 16)
- {
- int i;
- for (i = 0; i < outputsamples; i++)
- {
- int32_t audiobits = readbits(alac, alac->setinfo_sample_size);
- audiobits = SIGN_EXTENDED32(audiobits, alac->setinfo_sample_size);
- alac->outputsamples_buffer_a[i] = audiobits;
- }
- }
- else
- {
- int i;
- for (i = 0; i < outputsamples; i++)
- {
- int32_t audiobits;
- audiobits = readbits(alac, 16);
- /* special case of sign extension..
- * as we'll be ORing the low 16bits into this */
- audiobits = audiobits << (alac->setinfo_sample_size - 16);
- audiobits |= readbits(alac, alac->setinfo_sample_size - 16);
- audiobits = SignExtend24(audiobits);
- alac->outputsamples_buffer_a[i] = audiobits;
- }
- }
- uncompressed_bytes = 0; // always 0 for uncompressed
- }
- switch(alac->setinfo_sample_size)
- {
- case 16:
- {
- int i;
- for (i = 0; i < outputsamples; i++)
- {
- int16_t sample = alac->outputsamples_buffer_a[i];
- if (host_bigendian)
- _Swap16(sample);
- ((int16_t*)outbuffer)[i * alac->numchannels] = sample;
- }
- break;
- }
- case 24:
- {
- int i;
- for (i = 0; i < outputsamples; i++)
- {
- int32_t sample = alac->outputsamples_buffer_a[i];
- if (uncompressed_bytes)
- {
- uint32_t mask;
- sample = sample << (uncompressed_bytes * 8);
- mask = ~(0xFFFFFFFF << (uncompressed_bytes * 8));
- sample |= alac->uncompressed_bytes_buffer_a[i] & mask;
- }
- ((uint8_t*)outbuffer)[i * alac->numchannels * 3] = (sample) & 0xFF;
- ((uint8_t*)outbuffer)[i * alac->numchannels * 3 + 1] = (sample >> 8) & 0xFF;
- ((uint8_t*)outbuffer)[i * alac->numchannels * 3 + 2] = (sample >> 16) & 0xFF;
- }
- break;
- }
- case 20:
- case 32:
- _fprintf(stderr, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
- break;
- default:
- break;
- }
- break;
- }
- case 1: /* 2 channels */
- {
- int hassize;
- int isnotcompressed;
- int readsamplesize;
- int uncompressed_bytes;
- uint8_t interlacing_shift;
- uint8_t interlacing_leftweight;
- /* 2^result = something to do with output waiting.
- * perhaps matters if we read > 1 frame in a pass?
- */
- readbits(alac, 4);
- readbits(alac, 12); /* unknown, skip 12 bits */
- hassize = readbits(alac, 1); /* the output sample size is stored soon */
- uncompressed_bytes = readbits(alac, 2); /* the number of bytes in the (compressed) stream that are not compressed */
- isnotcompressed = readbits(alac, 1); /* whether the frame is compressed */
- if (hassize)
- {
- /* now read the number of samples,
- * as a 32bit integer */
- outputsamples = readbits(alac, 32);
- *outputsize = outputsamples * alac->bytespersample;
- }
- readsamplesize = alac->setinfo_sample_size - (uncompressed_bytes * 8) + 1;
- if (!isnotcompressed)
- { /* compressed */
- int16_t predictor_coef_table_a[32];
- int predictor_coef_num_a;
- int prediction_type_a;
- int prediction_quantitization_a;
- int ricemodifier_a;
- int16_t predictor_coef_table_b[32];
- int predictor_coef_num_b;
- int prediction_type_b;
- int prediction_quantitization_b;
- int ricemodifier_b;
- int i;
- interlacing_shift = readbits(alac, 8);
- interlacing_leftweight = readbits(alac, 8);
- /******** channel 1 ***********/
- prediction_type_a = readbits(alac, 4);
- prediction_quantitization_a = readbits(alac, 4);
- ricemodifier_a = readbits(alac, 3);
- predictor_coef_num_a = readbits(alac, 5);
- /* read the predictor table */
- for (i = 0; i < predictor_coef_num_a; i++)
- {
- predictor_coef_table_a[i] = (int16_t)readbits(alac, 16);
- }
- /******** channel 2 *********/
- prediction_type_b = readbits(alac, 4);
- prediction_quantitization_b = readbits(alac, 4);
- ricemodifier_b = readbits(alac, 3);
- predictor_coef_num_b = readbits(alac, 5);
- /* read the predictor table */
- for (i = 0; i < predictor_coef_num_b; i++)
- {
- predictor_coef_table_b[i] = (int16_t)readbits(alac, 16);
- }
- /*********************/
- if (uncompressed_bytes)
- { /* see mono case */
- int i;
- for (i = 0; i < outputsamples; i++)
- {
- alac->uncompressed_bytes_buffer_a[i] = readbits(alac, uncompressed_bytes * 8);
- alac->uncompressed_bytes_buffer_b[i] = readbits(alac, uncompressed_bytes * 8);
- }
- }
- /* channel 1 */
- entropy_rice_decode(alac,
- alac->predicterror_buffer_a,
- outputsamples,
- readsamplesize,
- alac->setinfo_rice_initialhistory,
- alac->setinfo_rice_kmodifier,
- ricemodifier_a * alac->setinfo_rice_historymult / 4,
- (1 << alac->setinfo_rice_kmodifier) - 1);
- if (prediction_type_a == 0)
- { /* adaptive fir */
- predictor_decompress_fir_adapt(alac->predicterror_buffer_a,
- alac->outputsamples_buffer_a,
- outputsamples,
- readsamplesize,
- predictor_coef_table_a,
- predictor_coef_num_a,
- prediction_quantitization_a);
- }
- else
- { /* see mono case */
- _fprintf(stderr, "FIXME: unhandled predicition type: %i\n", prediction_type_a);
- }
- /* channel 2 */
- entropy_rice_decode(alac,
- alac->predicterror_buffer_b,
- outputsamples,
- readsamplesize,
- alac->setinfo_rice_initialhistory,
- alac->setinfo_rice_kmodifier,
- ricemodifier_b * alac->setinfo_rice_historymult / 4,
- (1 << alac->setinfo_rice_kmodifier) - 1);
- if (prediction_type_b == 0)
- { /* adaptive fir */
- predictor_decompress_fir_adapt(alac->predicterror_buffer_b,
- alac->outputsamples_buffer_b,
- outputsamples,
- readsamplesize,
- predictor_coef_table_b,
- predictor_coef_num_b,
- prediction_quantitization_b);
- }
- else
- {
- _fprintf(stderr, "FIXME: unhandled predicition type: %i\n", prediction_type_b);
- }
- }
- else
- { /* not compressed, easy case */
- if (alac->setinfo_sample_size <= 16)
- {
- int i;
- for (i = 0; i < outputsamples; i++)
- {
- int32_t audiobits_a, audiobits_b;
- audiobits_a = readbits(alac, alac->setinfo_sample_size);
- audiobits_b = readbits(alac, alac->setinfo_sample_size);
- audiobits_a = SIGN_EXTENDED32(audiobits_a, alac->setinfo_sample_size);
- audiobits_b = SIGN_EXTENDED32(audiobits_b, alac->setinfo_sample_size);
- alac->outputsamples_buffer_a[i] = audiobits_a;
- alac->outputsamples_buffer_b[i] = audiobits_b;
- }
- }
- else
- {
- int i;
- for (i = 0; i < outputsamples; i++)
- {
- int32_t audiobits_a, audiobits_b;
- audiobits_a = readbits(alac, 16);
- audiobits_a = audiobits_a << (alac->setinfo_sample_size - 16);
- audiobits_a |= readbits(alac, alac->setinfo_sample_size - 16);
- audiobits_a = SignExtend24(audiobits_a);
- audiobits_b = readbits(alac, 16);
- audiobits_b = audiobits_b << (alac->setinfo_sample_size - 16);
- audiobits_b |= readbits(alac, alac->setinfo_sample_size - 16);
- audiobits_b = SignExtend24(audiobits_b);
- alac->outputsamples_buffer_a[i] = audiobits_a;
- alac->outputsamples_buffer_b[i] = audiobits_b;
- }
- }
- uncompressed_bytes = 0; // always 0 for uncompressed
- interlacing_shift = 0;
- interlacing_leftweight = 0;
- }
- switch(alac->setinfo_sample_size)
- {
- case 16:
- {
- deinterlace_16(alac->outputsamples_buffer_a,
- alac->outputsamples_buffer_b,
- (int16_t*)outbuffer,
- alac->numchannels,
- outputsamples,
- interlacing_shift,
- interlacing_leftweight);
- break;
- }
- case 24:
- {
- deinterlace_24(alac->outputsamples_buffer_a,
- alac->outputsamples_buffer_b,
- uncompressed_bytes,
- alac->uncompressed_bytes_buffer_a,
- alac->uncompressed_bytes_buffer_b,
- (int16_t*)outbuffer,
- alac->numchannels,
- outputsamples,
- interlacing_shift,
- interlacing_leftweight);
- break;
- }
- case 20:
- case 32:
- _fprintf(stderr, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
- break;
- default:
- break;
- }
- break;
- }
- }
- }
- alac_file *create_alac(int samplesize, int numchannels)
- {
- alac_file *newfile = malloc(sizeof(alac_file));
- newfile->samplesize = samplesize;
- newfile->numchannels = numchannels;
- newfile->bytespersample = (samplesize / 8) * numchannels;
- return newfile;
- }
- void delete_alac(alac_file *alac)
- {
- free(alac->predicterror_buffer_a);
- free(alac->predicterror_buffer_b);
- free(alac->outputsamples_buffer_a);
- free(alac->outputsamples_buffer_b);
- free(alac->uncompressed_bytes_buffer_a);
- free(alac->uncompressed_bytes_buffer_b);
- free(alac);
- }
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