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Diffstat (limited to 'plugins/alac/alac.c')
| -rw-r--r-- | plugins/alac/alac.c | 1198 |
1 files changed, 1198 insertions, 0 deletions
diff --git a/plugins/alac/alac.c b/plugins/alac/alac.c new file mode 100644 index 00000000..1779eb67 --- /dev/null +++ b/plugins/alac/alac.c @@ -0,0 +1,1198 @@ +/* + * 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. + * + */ + + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#ifdef _WIN32 + #include "stdint_win.h" +#else + #include <stdint.h> +#endif + +#include "decomp.h" + +#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) + +extern int host_bigendian; + +struct alac_file +{ + unsigned char *input_buffer; + int input_buffer_bitaccumulator; /* used so we can do arbitary + bit reads */ + + int samplesize; + int numchannels; + int bytespersample; + + + /* buffers */ + int32_t *predicterror_buffer_a; + int32_t *predicterror_buffer_b; + + int32_t *outputsamples_buffer_a; + int32_t *outputsamples_buffer_b; + + int32_t *uncompressed_bytes_buffer_a; + int32_t *uncompressed_bytes_buffer_b; + + + + /* stuff from setinfo */ + uint32_t setinfo_max_samples_per_frame; /* 0x1000 = 4096 */ /* max samples per frame? */ + uint8_t setinfo_7a; /* 0x00 */ + uint8_t setinfo_sample_size; /* 0x10 */ + uint8_t setinfo_rice_historymult; /* 0x28 */ + uint8_t setinfo_rice_initialhistory; /* 0x0a */ + uint8_t setinfo_rice_kmodifier; /* 0x0e */ + uint8_t setinfo_7f; /* 0x02 */ + uint16_t setinfo_80; /* 0x00ff */ + uint32_t setinfo_82; /* 0x000020e7 */ /* max sample size?? */ + uint32_t setinfo_86; /* 0x00069fe4 */ /* bit rate (avarge)?? */ + uint32_t setinfo_8a_rate; /* 0x0000ac44 */ + /* end setinfo stuff */ + +}; + + +static 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); + + ptr += 4; + + allocate_buffers(alac); + +} + +int +alac_get_samplerate(alac_file *alac) { + return alac->setinfo_8a_rate; +} + +/* 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__) && (defined(_X86) || defined(__i386) || defined(i386)) +/* for some reason the unrolled version (below) is + * actually faster than this. yay intel! + */ +static int count_leading_zeros(int input) +{ + int output = 0; + if (!input) return 32; + __asm("bsr %1, %0\n" + : "=r" (output) + : "r" (input)); + return (0x1f - output); +} +#elif defined(_MSC_VER) && 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; +} +#elif defined(__GNUC__) +static int count_leading_zeros(int input) +{ + return __builtin_clz(input); +} +#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. + +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; +} + +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++; + } + } +} + +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; + } +} + +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)); + memset (newfile, 0, sizeof (alac_file)); + + newfile->samplesize = samplesize; + newfile->numchannels = numchannels; + newfile->bytespersample = (samplesize / 8) * numchannels; + + return newfile; +} + +void alac_file_free (alac_file *alac) { + if (alac->predicterror_buffer_a) { + free (alac->predicterror_buffer_a); + } + if (alac->predicterror_buffer_b) { + free (alac->predicterror_buffer_b); + } + if (alac->outputsamples_buffer_a) { + free (alac->outputsamples_buffer_a); + } + if (alac->outputsamples_buffer_b) { + free (alac->outputsamples_buffer_b); + } + if (alac->uncompressed_bytes_buffer_a) { + free (alac->uncompressed_bytes_buffer_a); + } + if (alac->uncompressed_bytes_buffer_b) { + free (alac->uncompressed_bytes_buffer_b); + } + free (alac); +} + |