| @ -0,0 +1,658 @@ | |||
| /* | |||
| Copyright (c) 2023, Dominic Szablewski - https://phoboslab.org | |||
| SPDX-License-Identifier: MIT | |||
| QOA - The "Quite OK Audio" format for fast, lossy audio compression | |||
| -- Data Format | |||
| A QOA file has an 8 byte file header, followed by a number of frames. Each frame | |||
| consists of an 8 byte frame header, the current 8 byte en-/decoder state per | |||
| channel and 256 slices per channel. Each slice is 8 bytes wide and encodes 20 | |||
| samples of audio data. | |||
| Note that the last frame of a file may contain less than 256 slices per channel. | |||
| The last slice (per channel) in the last frame may contain less 20 samples, but | |||
| the slice will still be 8 bytes wide, with the unused samples zeroed out. | |||
| The samplerate and number of channels is only stated in the frame headers, but | |||
| not in the file header. A decoder may peek into the first frame of the file to | |||
| find these values. | |||
| In a valid QOA file all frames have the same number of channels and the same | |||
| samplerate. These restriction may be releaxed for streaming. This remains to | |||
| be decided. | |||
| All values in a QOA file are BIG ENDIAN. Luckily, EVERYTHING in a QOA file, | |||
| including the headers, is 64 bit aligned, so it's possible to read files with | |||
| just a read_u64() that does the byte swapping if neccessary. | |||
| In pseudocode, the file layout is as follows: | |||
| struct { | |||
| struct { | |||
| char magic[4]; // magic bytes 'qoaf' | |||
| uint32_t samples; // number of samples per channel in this file | |||
| } file_header; // = 64 bits | |||
| struct { | |||
| struct { | |||
| uint8_t num_channels; // number of channels | |||
| uint24_t samplerate; // samplerate in hz | |||
| uint16_t fsamples; // sample count per channel in this frame | |||
| uint16_t fsize; // frame size (including the frame header) | |||
| } frame_header; // = 64 bits | |||
| struct { | |||
| int16_t history[4]; // = 64 bits | |||
| int16_t weights[4]; // = 64 bits | |||
| } lms_state[num_channels]; | |||
| qoa_slice_t slices[256][num_channels]; // = 64 bits each | |||
| } frames[samples * channels / qoa_max_framesize()]; | |||
| } qoa_file; | |||
| Wheras the 64bit qoa_slice_t is defined as follows: | |||
| .- QOA_SLICE -- 64 bits, 20 samples --------------------------/ /------------. | |||
| | Byte[0] | Byte[1] | Byte[2] \ \ Byte[7] | | |||
| | 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 | 7 6 5 / / 2 1 0 | | |||
| |------------+--------+--------+--------+---------+---------+-\ \--+---------| | |||
| | sf_index | r00 | r01 | r02 | r03 | r04 | / / | r19 | | |||
| `-------------------------------------------------------------\ \------------` | |||
| `sf_index` defines the scalefactor to use for this slice as an index into the | |||
| qoa_scalefactor_tab[16] | |||
| `r00`--`r19` are the residuals for the individiual samples, divided by the | |||
| scalefactor and quantized by the qoa_quant_tab[]. | |||
| In the decoder, a prediction of the next sample is computed by multiplying the | |||
| state (the last four output samples) with the predictor. The residual from the | |||
| slice is then dequantized using the qoa_dequant_tab[] and added to the | |||
| prediction. The result is clamped to int16 to form the final output sample. | |||
| */ | |||
| /* ----------------------------------------------------------------------------- | |||
| Header - Public functions */ | |||
| #ifndef QOA_H | |||
| #define QOA_H | |||
| #ifdef __cplusplus | |||
| extern "C" { | |||
| #endif | |||
| #define QOA_MIN_FILESIZE 16 | |||
| #define QOA_MAX_CHANNELS 8 | |||
| #define QOA_SLICE_LEN 20 | |||
| #define QOA_SLICES_PER_FRAME 256 | |||
| #define QOA_FRAME_LEN (QOA_SLICES_PER_FRAME * QOA_SLICE_LEN) | |||
| #define QOA_LMS_LEN 4 | |||
| #define QOA_MAGIC 0x716f6166 /* 'qoaf' */ | |||
| #define QOA_FRAME_SIZE(channels, slices) \ | |||
| (8 + QOA_LMS_LEN * 4 * channels + 8 * slices * channels) | |||
| typedef struct { | |||
| int history[QOA_LMS_LEN]; | |||
| int weights[QOA_LMS_LEN]; | |||
| } qoa_lms_t; | |||
| typedef struct { | |||
| unsigned int channels; | |||
| unsigned int samplerate; | |||
| unsigned int samples; | |||
| qoa_lms_t lms[QOA_MAX_CHANNELS]; | |||
| #ifdef QOA_RECORD_TOTAL_ERROR | |||
| double error; | |||
| #endif | |||
| } qoa_desc; | |||
| unsigned int qoa_encode_header(qoa_desc *qoa, unsigned char *bytes); | |||
| unsigned int qoa_encode_frame(const short *sample_data, qoa_desc *qoa, unsigned int frame_len, unsigned char *bytes); | |||
| void *qoa_encode(const short *sample_data, qoa_desc *qoa, unsigned int *out_len); | |||
| unsigned int qoa_max_frame_size(qoa_desc *qoa); | |||
| unsigned int qoa_decode_header(const unsigned char *bytes, int size, qoa_desc *qoa); | |||
| unsigned int qoa_decode_frame(const unsigned char *bytes, unsigned int size, qoa_desc *qoa, short *sample_data, unsigned int *frame_len); | |||
| short *qoa_decode(const unsigned char *bytes, int size, qoa_desc *file); | |||
| #ifndef QOA_NO_STDIO | |||
| int qoa_write(const char *filename, const short *sample_data, qoa_desc *qoa); | |||
| void *qoa_read(const char *filename, qoa_desc *qoa); | |||
| #endif /* QOA_NO_STDIO */ | |||
| #ifdef __cplusplus | |||
| } | |||
| #endif | |||
| #endif /* QOA_H */ | |||
| /* ----------------------------------------------------------------------------- | |||
| Implementation */ | |||
| #ifdef QOA_IMPLEMENTATION | |||
| #include <stdlib.h> | |||
| #ifndef QOA_MALLOC | |||
| #define QOA_MALLOC(sz) malloc(sz) | |||
| #define QOA_FREE(p) free(p) | |||
| #endif | |||
| typedef unsigned long long qoa_uint64_t; | |||
| /* The quant_tab provides an index into the dequant_tab for residuals in the | |||
| range of -8 .. 8. It maps this range to just 3bits and becommes less accurate at | |||
| the higher end. Note that the residual zero is identical to the lowest positive | |||
| value. This is mostly fine, since the qoa_div() function always rounds away | |||
| from zero. */ | |||
| static int qoa_quant_tab[17] = { | |||
| 7, 7, 7, 5, 5, 3, 3, 1, /* -8..-1 */ | |||
| 0, /* 0 */ | |||
| 0, 2, 2, 4, 4, 6, 6, 6 /* 1.. 8 */ | |||
| }; | |||
| /* We have 16 different scalefactors. Like the quantized residuals these become | |||
| less accurate at the higher end. In theory, the highest scalefactor that we | |||
| would need to encode the highest 16bit residual is (2**16)/8 = 8192. However we | |||
| rely on the LMS filter to predict samples accurately enough that a maximum | |||
| residual of one quarter of the 16 bit range is high sufficent. I.e. with the | |||
| scalefactor 2048 times the quant range of 8 we can encode residuals up to 2**14. | |||
| The scalefactor values are computed as: | |||
| scalefactor_tab[s] <- round(pow(s + 1, 2.75)) */ | |||
| static int qoa_scalefactor_tab[16] = { | |||
| 1, 7, 21, 45, 84, 138, 211, 304, 421, 562, 731, 928, 1157, 1419, 1715, 2048 | |||
| }; | |||
| /* The reciprocal_tab maps each of the 16 scalefactors to their rounded | |||
| reciprocals 1/scalefactor. This allows us to calculate the scaled residuals in | |||
| the encoder with just one multiplication instead of an expensive division. We | |||
| do this in .16 fixed point with integers, instead of floats. | |||
| The reciprocal_tab is computed as: | |||
| reciprocal_tab[s] <- ((1<<16) + scalefactor_tab[s] - 1) / scalefactor_tab[s] */ | |||
| static int qoa_reciprocal_tab[16] = { | |||
| 65536, 9363, 3121, 1457, 781, 475, 311, 216, 156, 117, 90, 71, 57, 47, 39, 32 | |||
| }; | |||
| /* The dequant_tab maps each of the scalefactors and quantized residuals to | |||
| their unscaled & dequantized version. | |||
| Since qoa_div rounds away from the zero, the smallest entries are mapped to 3/4 | |||
| instead of 1. The dequant_tab assumes the following dequantized values for each | |||
| of the quant_tab indices and is computed as: | |||
| float dqt[8] = {0.75, -0.75, 2.5, -2.5, 4.5, -4.5, 7, -7}; | |||
| dequant_tab[s][q] <- round(scalefactor_tab[s] * dqt[q]) */ | |||
| static int qoa_dequant_tab[16][8] = { | |||
| { 1, -1, 3, -3, 5, -5, 7, -7}, | |||
| { 5, -5, 18, -18, 32, -32, 49, -49}, | |||
| { 16, -16, 53, -53, 95, -95, 147, -147}, | |||
| { 34, -34, 113, -113, 203, -203, 315, -315}, | |||
| { 63, -63, 210, -210, 378, -378, 588, -588}, | |||
| { 104, -104, 345, -345, 621, -621, 966, -966}, | |||
| { 158, -158, 528, -528, 950, -950, 1477, -1477}, | |||
| { 228, -228, 760, -760, 1368, -1368, 2128, -2128}, | |||
| { 316, -316, 1053, -1053, 1895, -1895, 2947, -2947}, | |||
| { 422, -422, 1405, -1405, 2529, -2529, 3934, -3934}, | |||
| { 548, -548, 1828, -1828, 3290, -3290, 5117, -5117}, | |||
| { 696, -696, 2320, -2320, 4176, -4176, 6496, -6496}, | |||
| { 868, -868, 2893, -2893, 5207, -5207, 8099, -8099}, | |||
| {1064, -1064, 3548, -3548, 6386, -6386, 9933, -9933}, | |||
| {1286, -1286, 4288, -4288, 7718, -7718, 12005, -12005}, | |||
| {1536, -1536, 5120, -5120, 9216, -9216, 14336, -14336}, | |||
| }; | |||
| /* The Least Mean Squares Filter is the heart of QOA. It predicts the next | |||
| sample based on the previous 4 reconstructed samples. It does so by continuously | |||
| adjusting 4 weights based on the residual of the previous prediction. | |||
| The next sample is predicted as the sum of (weight[i] * history[i]). | |||
| The adjustment of the weights is done with a "Sign-Sign-LMS" that adds or | |||
| subtracts the residual to each weight, based on the corresponding sample from | |||
| the history. This, suprisingly, is sufficent to get worthwhile predictions. | |||
| This is all done with fixed point integers. Hence the right-shifts when updating | |||
| the weights and calculating the prediction. */ | |||
| static int qoa_lms_predict(qoa_lms_t *lms) { | |||
| int prediction = 0; | |||
| for (int i = 0; i < QOA_LMS_LEN; i++) { | |||
| prediction += lms->weights[i] * lms->history[i]; | |||
| } | |||
| return prediction >> 13; | |||
| } | |||
| static void qoa_lms_update(qoa_lms_t *lms, int sample, int residual) { | |||
| int delta = residual >> 4; | |||
| for (int i = 0; i < QOA_LMS_LEN; i++) { | |||
| lms->weights[i] += lms->history[i] < 0 ? -delta : delta; | |||
| } | |||
| for (int i = 0; i < QOA_LMS_LEN-1; i++) { | |||
| lms->history[i] = lms->history[i+1]; | |||
| } | |||
| lms->history[QOA_LMS_LEN-1] = sample; | |||
| } | |||
| /* qoa_div() implements a rounding division, but avoids rounding to zero for | |||
| small numbers. E.g. 0.1 will be rounded to 1. Note that 0 itself still | |||
| returns as 0, which is handled in the qoa_quant_tab[]. | |||
| qoa_div() takes an index into the .16 fixed point qoa_reciprocal_tab as an | |||
| argument, so it can do the division with a cheaper integer multiplication. */ | |||
| static inline int qoa_div(int v, int scalefactor) { | |||
| int reciprocal = qoa_reciprocal_tab[scalefactor]; | |||
| int n = (v * reciprocal + (1 << 15)) >> 16; | |||
| n = n + ((v > 0) - (v < 0)) - ((n > 0) - (n < 0)); /* round away from 0 */ | |||
| return n; | |||
| } | |||
| static inline int qoa_clamp(int v, int min, int max) { | |||
| return (v < min) ? min : (v > max) ? max : v; | |||
| } | |||
| static inline qoa_uint64_t qoa_read_u64(const unsigned char *bytes, unsigned int *p) { | |||
| qoa_uint64_t v = | |||
| (qoa_uint64_t)bytes[(*p)+0] << 56 | (qoa_uint64_t)bytes[(*p)+1] << 48 | | |||
| (qoa_uint64_t)bytes[(*p)+2] << 40 | (qoa_uint64_t)bytes[(*p)+3] << 32 | | |||
| (qoa_uint64_t)bytes[(*p)+4] << 24 | (qoa_uint64_t)bytes[(*p)+5] << 16 | | |||
| (qoa_uint64_t)bytes[(*p)+6] << 8 | (qoa_uint64_t)bytes[(*p)+7]; | |||
| *p += 8; | |||
| return v; | |||
| } | |||
| static inline void qoa_write_u64(qoa_uint64_t v, unsigned char *bytes, unsigned int *p) { | |||
| bytes[(*p)++] = (v >> 56) & 0xff; | |||
| bytes[(*p)++] = (v >> 48) & 0xff; | |||
| bytes[(*p)++] = (v >> 40) & 0xff; | |||
| bytes[(*p)++] = (v >> 32) & 0xff; | |||
| bytes[(*p)++] = (v >> 24) & 0xff; | |||
| bytes[(*p)++] = (v >> 16) & 0xff; | |||
| bytes[(*p)++] = (v >> 8) & 0xff; | |||
| bytes[(*p)++] = (v >> 0) & 0xff; | |||
| } | |||
| /* ----------------------------------------------------------------------------- | |||
| Encoder */ | |||
| unsigned int qoa_encode_header(qoa_desc *qoa, unsigned char *bytes) { | |||
| unsigned int p = 0; | |||
| qoa_write_u64(((qoa_uint64_t)QOA_MAGIC << 32) | qoa->samples, bytes, &p); | |||
| return p; | |||
| } | |||
| unsigned int qoa_encode_frame(const short *sample_data, qoa_desc *qoa, unsigned int frame_len, unsigned char *bytes) { | |||
| unsigned int channels = qoa->channels; | |||
| unsigned int p = 0; | |||
| unsigned int slices = (frame_len + QOA_SLICE_LEN - 1) / QOA_SLICE_LEN; | |||
| unsigned int frame_size = QOA_FRAME_SIZE(channels, slices); | |||
| /* Write the frame header */ | |||
| qoa_write_u64(( | |||
| (qoa_uint64_t)qoa->channels << 56 | | |||
| (qoa_uint64_t)qoa->samplerate << 32 | | |||
| (qoa_uint64_t)frame_len << 16 | | |||
| (qoa_uint64_t)frame_size | |||
| ), bytes, &p); | |||
| /* Write the current LMS state */ | |||
| for (int c = 0; c < channels; c++) { | |||
| qoa_uint64_t weights = 0; | |||
| qoa_uint64_t history = 0; | |||
| for (int i = 0; i < QOA_LMS_LEN; i++) { | |||
| history = (history << 16) | (qoa->lms[c].history[i] & 0xffff); | |||
| weights = (weights << 16) | (qoa->lms[c].weights[i] & 0xffff); | |||
| } | |||
| qoa_write_u64(history, bytes, &p); | |||
| qoa_write_u64(weights, bytes, &p); | |||
| } | |||
| /* We encode all samples with the channels interleaved on a slice level. | |||
| E.g. for stereo: (ch-0, slice 0), (ch 1, slice 0), (ch 0, slice 1), ...*/ | |||
| for (int sample_index = 0; sample_index < frame_len; sample_index += QOA_SLICE_LEN) { | |||
| for (int c = 0; c < channels; c++) { | |||
| int slice_len = qoa_clamp(QOA_SLICE_LEN, 0, frame_len - sample_index); | |||
| int slice_start = sample_index * channels + c; | |||
| int slice_end = (sample_index + slice_len) * channels + c; | |||
| /* Brute for search for the best scalefactor. Just go through all | |||
| 16 scalefactors, encode all samples for the current slice and | |||
| meassure the total squared error. */ | |||
| qoa_uint64_t best_error = -1; | |||
| qoa_uint64_t best_slice; | |||
| qoa_lms_t best_lms; | |||
| for (int scalefactor = 0; scalefactor < 16; scalefactor++) { | |||
| /* We have to reset the LMS state to the last known good one | |||
| before trying each scalefactor, as each pass updates the LMS | |||
| state when encoding. */ | |||
| qoa_lms_t lms = qoa->lms[c]; | |||
| qoa_uint64_t slice = scalefactor; | |||
| qoa_uint64_t current_error = 0; | |||
| for (int si = slice_start; si < slice_end; si += channels) { | |||
| int sample = sample_data[si]; | |||
| int predicted = qoa_lms_predict(&lms); | |||
| int residual = sample - predicted; | |||
| int scaled = qoa_div(residual, scalefactor); | |||
| int clamped = qoa_clamp(scaled, -8, 8); | |||
| int quantized = qoa_quant_tab[clamped + 8]; | |||
| int dequantized = qoa_dequant_tab[scalefactor][quantized]; | |||
| int reconstructed = qoa_clamp(predicted + dequantized, -32768, 32767); | |||
| int error = (sample - reconstructed); | |||
| current_error += error * error; | |||
| if (current_error > best_error) { | |||
| break; | |||
| } | |||
| qoa_lms_update(&lms, reconstructed, dequantized); | |||
| slice = (slice << 3) | quantized; | |||
| } | |||
| if (current_error < best_error) { | |||
| best_error = current_error; | |||
| best_slice = slice; | |||
| best_lms = lms; | |||
| } | |||
| } | |||
| qoa->lms[c] = best_lms; | |||
| #ifdef QOA_RECORD_TOTAL_ERROR | |||
| qoa->error += best_error; | |||
| #endif | |||
| /* If this slice was shorter than QOA_SLICE_LEN, we have to left- | |||
| shift all encoded data, to ensure the rightmost bits are the empty | |||
| ones. This should only happen in the last frame of a file as all | |||
| slices are completely filled otherwise. */ | |||
| best_slice <<= (QOA_SLICE_LEN - slice_len) * 3; | |||
| qoa_write_u64(best_slice, bytes, &p); | |||
| } | |||
| } | |||
| return p; | |||
| } | |||
| void *qoa_encode(const short *sample_data, qoa_desc *qoa, unsigned int *out_len) { | |||
| if ( | |||
| qoa->samples == 0 || | |||
| qoa->samplerate == 0 || qoa->samplerate > 0xffffff || | |||
| qoa->channels == 0 || qoa->channels > QOA_MAX_CHANNELS | |||
| ) { | |||
| return NULL; | |||
| } | |||
| /* Calculate the encoded size and allocate */ | |||
| unsigned int num_frames = (qoa->samples + QOA_FRAME_LEN-1) / QOA_FRAME_LEN; | |||
| unsigned int num_slices = (qoa->samples + QOA_SLICE_LEN-1) / QOA_SLICE_LEN; | |||
| unsigned int encoded_size = 8 + /* 8 byte file header */ | |||
| num_frames * 8 + /* 8 byte frame headers */ | |||
| num_frames * QOA_LMS_LEN * 4 * qoa->channels + /* 4 * 4 bytes lms state per channel */ | |||
| num_slices * 8 * qoa->channels; /* 8 byte slices */ | |||
| unsigned char *bytes = QOA_MALLOC(encoded_size); | |||
| for (int c = 0; c < qoa->channels; c++) { | |||
| /* Set the initial LMS weights to {0, 0, -1, 2}. This helps with the | |||
| prediction of the first few ms of a file. */ | |||
| qoa->lms[c].weights[0] = 0; | |||
| qoa->lms[c].weights[1] = 0; | |||
| qoa->lms[c].weights[2] = -(1<<13); | |||
| qoa->lms[c].weights[3] = (1<<14); | |||
| /* Explicitly set the history samples to 0, as we might have some | |||
| garbage in there. */ | |||
| for (int i = 0; i < QOA_LMS_LEN; i++) { | |||
| qoa->lms[c].history[i] = 0; | |||
| } | |||
| } | |||
| /* Encode the header and go through all frames */ | |||
| unsigned int p = qoa_encode_header(qoa, bytes); | |||
| #ifdef QOA_RECORD_TOTAL_ERROR | |||
| qoa->error = 0; | |||
| #endif | |||
| int frame_len = QOA_FRAME_LEN; | |||
| for (int sample_index = 0; sample_index < qoa->samples; sample_index += frame_len) { | |||
| frame_len = qoa_clamp(QOA_FRAME_LEN, 0, qoa->samples - sample_index); | |||
| const short *frame_samples = sample_data + sample_index * qoa->channels; | |||
| unsigned int frame_size = qoa_encode_frame(frame_samples, qoa, frame_len, bytes + p); | |||
| p += frame_size; | |||
| } | |||
| *out_len = p; | |||
| return bytes; | |||
| } | |||
| /* ----------------------------------------------------------------------------- | |||
| Decoder */ | |||
| unsigned int qoa_max_frame_size(qoa_desc *qoa) { | |||
| return QOA_FRAME_SIZE(qoa->channels, QOA_SLICES_PER_FRAME); | |||
| } | |||
| unsigned int qoa_decode_header(const unsigned char *bytes, int size, qoa_desc *qoa) { | |||
| unsigned int p = 0; | |||
| if (size < QOA_MIN_FILESIZE) { | |||
| return 0; | |||
| } | |||
| /* Read the file header, verify the magic number ('qoaf') and read the | |||
| total number of samples. */ | |||
| qoa_uint64_t file_header = qoa_read_u64(bytes, &p); | |||
| if ((file_header >> 32) != QOA_MAGIC) { | |||
| return 0; | |||
| } | |||
| qoa->samples = file_header & 0xffffffff; | |||
| if (!qoa->samples) { | |||
| return 0; | |||
| } | |||
| /* Peek into the first frame header to get the number of channels and | |||
| the samplerate. */ | |||
| qoa_uint64_t frame_header = qoa_read_u64(bytes, &p); | |||
| qoa->channels = (frame_header >> 56) & 0x0000ff; | |||
| qoa->samplerate = (frame_header >> 32) & 0xffffff; | |||
| if (qoa->channels == 0 || qoa->samples == 0 || qoa->samplerate == 0) { | |||
| return 0; | |||
| } | |||
| return 8; | |||
| } | |||
| unsigned int qoa_decode_frame(const unsigned char *bytes, unsigned int size, qoa_desc *qoa, short *sample_data, unsigned int *frame_len) { | |||
| unsigned int p = 0; | |||
| *frame_len = 0; | |||
| if (size < 8 + QOA_LMS_LEN * 4 * qoa->channels) { | |||
| return 0; | |||
| } | |||
| /* Read and verify the frame header */ | |||
| qoa_uint64_t frame_header = qoa_read_u64(bytes, &p); | |||
| int channels = (frame_header >> 56) & 0x0000ff; | |||
| int samplerate = (frame_header >> 32) & 0xffffff; | |||
| int samples = (frame_header >> 16) & 0x00ffff; | |||
| int frame_size = (frame_header ) & 0x00ffff; | |||
| int data_size = frame_size - 8 - QOA_LMS_LEN * 4 * channels; | |||
| int num_slices = data_size / 8; | |||
| int max_total_samples = num_slices * QOA_SLICE_LEN; | |||
| if ( | |||
| channels != qoa->channels || | |||
| samplerate != qoa->samplerate || | |||
| frame_size > size || | |||
| samples * channels > max_total_samples | |||
| ) { | |||
| return 0; | |||
| } | |||
| /* Read the LMS state: 4 x 2 bytes history, 4 x 2 bytes weights per channel */ | |||
| for (int c = 0; c < channels; c++) { | |||
| qoa_uint64_t history = qoa_read_u64(bytes, &p); | |||
| qoa_uint64_t weights = qoa_read_u64(bytes, &p); | |||
| for (int i = 0; i < QOA_LMS_LEN; i++) { | |||
| qoa->lms[c].history[i] = ((signed short)(history >> 48)); | |||
| history <<= 16; | |||
| qoa->lms[c].weights[i] = ((signed short)(weights >> 48)); | |||
| weights <<= 16; | |||
| } | |||
| } | |||
| /* Decode all slices for all channels in this frame */ | |||
| for (int sample_index = 0; sample_index < samples; sample_index += QOA_SLICE_LEN) { | |||
| for (int c = 0; c < channels; c++) { | |||
| qoa_uint64_t slice = qoa_read_u64(bytes, &p); | |||
| int scalefactor = (slice >> 60) & 0xf; | |||
| int slice_start = sample_index * channels + c; | |||
| int slice_end = qoa_clamp(sample_index + QOA_SLICE_LEN, 0, samples) * channels + c; | |||
| for (int si = slice_start; si < slice_end; si += channels) { | |||
| int predicted = qoa_lms_predict(&qoa->lms[c]); | |||
| int quantized = (slice >> 57) & 0x7; | |||
| int dequantized = qoa_dequant_tab[scalefactor][quantized]; | |||
| int reconstructed = qoa_clamp(predicted + dequantized, -32768, 32767); | |||
| sample_data[si] = reconstructed; | |||
| slice <<= 3; | |||
| qoa_lms_update(&qoa->lms[c], reconstructed, dequantized); | |||
| } | |||
| } | |||
| } | |||
| *frame_len = samples; | |||
| return p; | |||
| } | |||
| short *qoa_decode(const unsigned char *bytes, int size, qoa_desc *qoa) { | |||
| unsigned int p = qoa_decode_header(bytes, size, qoa); | |||
| if (!p) { | |||
| return NULL; | |||
| } | |||
| /* Calculate the required size of the sample buffer and allocate */ | |||
| int total_samples = qoa->samples * qoa->channels; | |||
| short *sample_data = QOA_MALLOC(total_samples * sizeof(short)); | |||
| unsigned int sample_index = 0; | |||
| unsigned int frame_len; | |||
| unsigned int frame_size; | |||
| /* Decode all frames */ | |||
| do { | |||
| short *sample_ptr = sample_data + sample_index * qoa->channels; | |||
| frame_size = qoa_decode_frame(bytes + p, size - p, qoa, sample_ptr, &frame_len); | |||
| p += frame_size; | |||
| sample_index += frame_len; | |||
| } while (frame_size && sample_index < qoa->samples); | |||
| qoa->samples = sample_index; | |||
| return sample_data; | |||
| } | |||
| /* ----------------------------------------------------------------------------- | |||
| File read/write convenience functions */ | |||
| #ifndef QOA_NO_STDIO | |||
| #include <stdio.h> | |||
| int qoa_write(const char *filename, const short *sample_data, qoa_desc *qoa) { | |||
| FILE *f = fopen(filename, "wb"); | |||
| unsigned int size; | |||
| void *encoded; | |||
| if (!f) { | |||
| return 0; | |||
| } | |||
| encoded = qoa_encode(sample_data, qoa, &size); | |||
| if (!encoded) { | |||
| fclose(f); | |||
| return 0; | |||
| } | |||
| fwrite(encoded, 1, size, f); | |||
| fclose(f); | |||
| QOA_FREE(encoded); | |||
| return size; | |||
| } | |||
| void *qoa_read(const char *filename, qoa_desc *qoa) { | |||
| FILE *f = fopen(filename, "rb"); | |||
| int size, bytes_read; | |||
| void *data; | |||
| short *sample_data; | |||
| if (!f) { | |||
| return NULL; | |||
| } | |||
| fseek(f, 0, SEEK_END); | |||
| size = ftell(f); | |||
| if (size <= 0) { | |||
| fclose(f); | |||
| return NULL; | |||
| } | |||
| fseek(f, 0, SEEK_SET); | |||
| data = QOA_MALLOC(size); | |||
| if (!data) { | |||
| fclose(f); | |||
| return NULL; | |||
| } | |||
| bytes_read = fread(data, 1, size, f); | |||
| fclose(f); | |||
| sample_data = qoa_decode(data, bytes_read, qoa); | |||
| QOA_FREE(data); | |||
| return sample_data; | |||
| } | |||
| #endif /* QOA_NO_STDIO */ | |||
| #endif /* QOA_IMPLEMENTATION */ | |||