/* * Audio Processing Technology codec for Bluetooth (aptX) * * Copyright (C) 2017 Aurelien Jacobs * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavutil/intreadwrite.h" #include "avcodec.h" #include "internal.h" #include "mathops.h" #include "audio_frame_queue.h" enum channels { LEFT, RIGHT, NB_CHANNELS }; enum subbands { LF, // Low Frequency (0-5.5 kHz) MLF, // Medium-Low Frequency (5.5-11kHz) MHF, // Medium-High Frequency (11-16.5kHz) HF, // High Frequency (16.5-22kHz) NB_SUBBANDS }; #define NB_FILTERS 2 #define FILTER_TAPS 16 typedef struct { int pos; int32_t buffer[2*FILTER_TAPS]; } FilterSignal; typedef struct { FilterSignal outer_filter_signal[NB_FILTERS]; FilterSignal inner_filter_signal[NB_FILTERS][NB_FILTERS]; } QMFAnalysis; typedef struct { int32_t quantized_sample; int32_t quantized_sample_parity_change; int32_t error; } Quantize; typedef struct { int32_t quantization_factor; int32_t factor_select; int32_t reconstructed_difference; } InvertQuantize; typedef struct { int32_t prev_sign[2]; int32_t s_weight[2]; int32_t d_weight[24]; int32_t pos; int32_t reconstructed_differences[48]; int32_t previous_reconstructed_sample; int32_t predicted_difference; int32_t predicted_sample; } Prediction; typedef struct { int32_t codeword_history; int32_t dither_parity; int32_t dither[NB_SUBBANDS]; QMFAnalysis qmf; Quantize quantize[NB_SUBBANDS]; InvertQuantize invert_quantize[NB_SUBBANDS]; Prediction prediction[NB_SUBBANDS]; } Channel; typedef struct { int32_t sync_idx; Channel channels[NB_CHANNELS]; AudioFrameQueue afq; } AptXContext; static const int32_t quantize_intervals_LF[65] = { -9948, 9948, 29860, 49808, 69822, 89926, 110144, 130502, 151026, 171738, 192666, 213832, 235264, 256982, 279014, 301384, 324118, 347244, 370790, 394782, 419250, 444226, 469742, 495832, 522536, 549890, 577936, 606720, 636290, 666700, 698006, 730270, 763562, 797958, 833538, 870398, 908640, 948376, 989740, 1032874, 1077948, 1125150, 1174700, 1226850, 1281900, 1340196, 1402156, 1468282, 1539182, 1615610, 1698514, 1789098, 1888944, 2000168, 2125700, 2269750, 2438670, 2642660, 2899462, 3243240, 3746078, 4535138, 5664098, 7102424, 8897462, }; static const int32_t invert_quantize_dither_factors_LF[65] = { 9948, 9948, 9962, 9988, 10026, 10078, 10142, 10218, 10306, 10408, 10520, 10646, 10784, 10934, 11098, 11274, 11462, 11664, 11880, 12112, 12358, 12618, 12898, 13194, 13510, 13844, 14202, 14582, 14988, 15422, 15884, 16380, 16912, 17484, 18098, 18762, 19480, 20258, 21106, 22030, 23044, 24158, 25390, 26760, 28290, 30008, 31954, 34172, 36728, 39700, 43202, 47382, 52462, 58762, 66770, 77280, 91642, 112348, 144452, 199326, 303512, 485546, 643414, 794914, 1000124, }; static const int32_t quantize_dither_factors_LF[65] = { 0, 4, 7, 10, 13, 16, 19, 22, 26, 28, 32, 35, 38, 41, 44, 47, 51, 54, 58, 62, 65, 70, 74, 79, 84, 90, 95, 102, 109, 116, 124, 133, 143, 154, 166, 180, 195, 212, 231, 254, 279, 308, 343, 383, 430, 487, 555, 639, 743, 876, 1045, 1270, 1575, 2002, 2628, 3591, 5177, 8026, 13719, 26047, 45509, 39467, 37875, 51303, 0, }; static const int16_t quantize_factor_select_offset_LF[65] = { 0, -21, -19, -17, -15, -12, -10, -8, -6, -4, -1, 1, 3, 6, 8, 10, 13, 15, 18, 20, 23, 26, 29, 31, 34, 37, 40, 43, 47, 50, 53, 57, 60, 64, 68, 72, 76, 80, 85, 89, 94, 99, 105, 110, 116, 123, 129, 136, 144, 152, 161, 171, 182, 194, 207, 223, 241, 263, 291, 328, 382, 467, 522, 522, 522, }; static const int32_t quantize_intervals_MLF[9] = { -89806, 89806, 278502, 494338, 759442, 1113112, 1652322, 2720256, 5190186, }; static const int32_t invert_quantize_dither_factors_MLF[9] = { 89806, 89806, 98890, 116946, 148158, 205512, 333698, 734236, 1735696, }; static const int32_t quantize_dither_factors_MLF[9] = { 0, 2271, 4514, 7803, 14339, 32047, 100135, 250365, 0, }; static const int16_t quantize_factor_select_offset_MLF[9] = { 0, -14, 6, 29, 58, 96, 154, 270, 521, }; static const int32_t quantize_intervals_MHF[3] = { -194080, 194080, 890562, }; static const int32_t invert_quantize_dither_factors_MHF[3] = { 194080, 194080, 502402, }; static const int32_t quantize_dither_factors_MHF[3] = { 0, 77081, 0, }; static const int16_t quantize_factor_select_offset_MHF[3] = { 0, -33, 136, }; static const int32_t quantize_intervals_HF[5] = { -163006, 163006, 542708, 1120554, 2669238, }; static const int32_t invert_quantize_dither_factors_HF[5] = { 163006, 163006, 216698, 361148, 1187538, }; static const int32_t quantize_dither_factors_HF[5] = { 0, 13423, 36113, 206598, 0, }; static const int16_t quantize_factor_select_offset_HF[5] = { 0, -8, 33, 95, 262, }; typedef const struct { const int32_t *quantize_intervals; const int32_t *invert_quantize_dither_factors; const int32_t *quantize_dither_factors; const int16_t *quantize_factor_select_offset; int tables_size; int32_t quantized_bits; int32_t prediction_order; } ConstTables; static ConstTables tables[NB_SUBBANDS] = { [LF] = { quantize_intervals_LF, invert_quantize_dither_factors_LF, quantize_dither_factors_LF, quantize_factor_select_offset_LF, FF_ARRAY_ELEMS(quantize_intervals_LF), 7, 24 }, [MLF] = { quantize_intervals_MLF, invert_quantize_dither_factors_MLF, quantize_dither_factors_MLF, quantize_factor_select_offset_MLF, FF_ARRAY_ELEMS(quantize_intervals_MLF), 4, 12 }, [MHF] = { quantize_intervals_MHF, invert_quantize_dither_factors_MHF, quantize_dither_factors_MHF, quantize_factor_select_offset_MHF, FF_ARRAY_ELEMS(quantize_intervals_MHF), 2, 6 }, [HF] = { quantize_intervals_HF, invert_quantize_dither_factors_HF, quantize_dither_factors_HF, quantize_factor_select_offset_HF, FF_ARRAY_ELEMS(quantize_intervals_HF), 3, 12 }, }; static const int16_t quantization_factors[32] = { 2048, 2093, 2139, 2186, 2233, 2282, 2332, 2383, 2435, 2489, 2543, 2599, 2656, 2714, 2774, 2834, 2896, 2960, 3025, 3091, 3158, 3228, 3298, 3371, 3444, 3520, 3597, 3676, 3756, 3838, 3922, 4008, }; /* Rounded right shift with optionnal clipping */ #define RSHIFT_SIZE(size) \ av_always_inline \ static int##size##_t rshift##size(int##size##_t value, int shift) \ { \ int##size##_t rounding = (int##size##_t)1 << (shift - 1); \ int##size##_t mask = ((int##size##_t)1 << (shift + 1)) - 1; \ return ((value + rounding) >> shift) - ((value & mask) == rounding); \ } \ av_always_inline \ static int##size##_t rshift##size##_clip24(int##size##_t value, int shift) \ { \ return av_clip_intp2(rshift##size(value, shift), 23); \ } RSHIFT_SIZE(32) RSHIFT_SIZE(64) av_always_inline static void aptx_update_codeword_history(Channel *channel) { int32_t cw = ((channel->quantize[0].quantized_sample & 3) << 0) + ((channel->quantize[1].quantized_sample & 2) << 1) + ((channel->quantize[2].quantized_sample & 1) << 3); channel->codeword_history = (cw << 8) + (channel->codeword_history << 4); } static void aptx_generate_dither(Channel *channel) { int subband; int64_t m; int32_t d; aptx_update_codeword_history(channel); m = (int64_t)5184443 * (channel->codeword_history >> 7); d = (m << 2) + (m >> 22); for (subband = 0; subband < NB_SUBBANDS; subband++) channel->dither[subband] = d << (23 - 5*subband); channel->dither_parity = (d >> 25) & 1; } /* * Convolution filter coefficients for the outer QMF of the QMF tree. * The 2 sets are a mirror of each other. */ static const int32_t aptx_qmf_outer_coeffs[NB_FILTERS][FILTER_TAPS] = { { 730, -413, -9611, 43626, -121026, 269973, -585547, 2801966, 697128, -160481, 27611, 8478, -10043, 3511, 688, -897, }, { -897, 688, 3511, -10043, 8478, 27611, -160481, 697128, 2801966, -585547, 269973, -121026, 43626, -9611, -413, 730, }, }; /* * Convolution filter coefficients for the inner QMF of the QMF tree. * The 2 sets are a mirror of each other. */ static const int32_t aptx_qmf_inner_coeffs[NB_FILTERS][FILTER_TAPS] = { { 1033, -584, -13592, 61697, -171156, 381799, -828088, 3962579, 985888, -226954, 39048, 11990, -14203, 4966, 973, -1268, }, { -1268, 973, 4966, -14203, 11990, 39048, -226954, 985888, 3962579, -828088, 381799, -171156, 61697, -13592, -584, 1033, }, }; /* * Push one sample into a circular signal buffer. */ av_always_inline static void aptx_qmf_filter_signal_push(FilterSignal *signal, int32_t sample) { signal->buffer[signal->pos ] = sample; signal->buffer[signal->pos+FILTER_TAPS] = sample; signal->pos = (signal->pos + 1) & (FILTER_TAPS - 1); } /* * Compute the convolution of the signal with the coefficients, and reduce * to 24 bits by applying the specified right shifting. */ av_always_inline static int32_t aptx_qmf_convolution(FilterSignal *signal, const int32_t coeffs[FILTER_TAPS], int shift) { int32_t *sig = &signal->buffer[signal->pos]; int64_t e = 0; int i; for (i = 0; i < FILTER_TAPS; i++) e += MUL64(sig[i], coeffs[i]); return rshift64_clip24(e, shift); } /* * Half-band QMF analysis filter realized with a polyphase FIR filter. * Split into 2 subbands and downsample by 2. * So for each pair of samples that goes in, one sample goes out, * split into 2 separate subbands. */ av_always_inline static void aptx_qmf_polyphase_analysis(FilterSignal signal[NB_FILTERS], const int32_t coeffs[NB_FILTERS][FILTER_TAPS], int shift, int32_t samples[NB_FILTERS], int32_t *low_subband_output, int32_t *high_subband_output) { int32_t subbands[NB_FILTERS]; int i; for (i = 0; i < NB_FILTERS; i++) { aptx_qmf_filter_signal_push(&signal[i], samples[NB_FILTERS-1-i]); subbands[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift); } *low_subband_output = av_clip_intp2(subbands[0] + subbands[1], 23); *high_subband_output = av_clip_intp2(subbands[0] - subbands[1], 23); } /* * Two stage QMF analysis tree. * Split 4 input samples into 4 subbands and downsample by 4. * So for each group of 4 samples that goes in, one sample goes out, * split into 4 separate subbands. */ static void aptx_qmf_tree_analysis(QMFAnalysis *qmf, int32_t samples[4], int32_t subband_samples[4]) { int32_t intermediate_samples[4]; int i; /* Split 4 input samples into 2 intermediate subbands downsampled to 2 samples */ for (i = 0; i < 2; i++) aptx_qmf_polyphase_analysis(qmf->outer_filter_signal, aptx_qmf_outer_coeffs, 23, &samples[2*i], &intermediate_samples[0+i], &intermediate_samples[2+i]); /* Split 2 intermediate subband samples into 4 final subbands downsampled to 1 sample */ for (i = 0; i < 2; i++) aptx_qmf_polyphase_analysis(qmf->inner_filter_signal[i], aptx_qmf_inner_coeffs, 23, &intermediate_samples[2*i], &subband_samples[2*i+0], &subband_samples[2*i+1]); } /* * Half-band QMF synthesis filter realized with a polyphase FIR filter. * Join 2 subbands and upsample by 2. * So for each 2 subbands sample that goes in, a pair of samples goes out. */ av_always_inline static void aptx_qmf_polyphase_synthesis(FilterSignal signal[NB_FILTERS], const int32_t coeffs[NB_FILTERS][FILTER_TAPS], int shift, int32_t low_subband_input, int32_t high_subband_input, int32_t samples[NB_FILTERS]) { int32_t subbands[NB_FILTERS]; int i; subbands[0] = low_subband_input + high_subband_input; subbands[1] = low_subband_input - high_subband_input; for (i = 0; i < NB_FILTERS; i++) { aptx_qmf_filter_signal_push(&signal[i], subbands[1-i]); samples[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift); } } /* * Two stage QMF synthesis tree. * Join 4 subbands and upsample by 4. * So for each 4 subbands sample that goes in, a group of 4 samples goes out. */ static void aptx_qmf_tree_synthesis(QMFAnalysis *qmf, int32_t subband_samples[4], int32_t samples[4]) { int32_t intermediate_samples[4]; int i; /* Join 4 subbands into 2 intermediate subbands upsampled to 2 samples. */ for (i = 0; i < 2; i++) aptx_qmf_polyphase_synthesis(qmf->inner_filter_signal[i], aptx_qmf_inner_coeffs, 22, subband_samples[2*i+0], subband_samples[2*i+1], &intermediate_samples[2*i]); /* Join 2 samples from intermediate subbands upsampled to 4 samples. */ for (i = 0; i < 2; i++) aptx_qmf_polyphase_synthesis(qmf->outer_filter_signal, aptx_qmf_outer_coeffs, 21, intermediate_samples[0+i], intermediate_samples[2+i], &samples[2*i]); } av_always_inline static int32_t aptx_bin_search(int32_t value, int32_t factor, const int32_t *intervals, int32_t nb_intervals) { int32_t idx = 0; int i; for (i = nb_intervals >> 1; i > 0; i >>= 1) if (MUL64(factor, intervals[idx + i]) <= ((int64_t)value << 24)) idx += i; return idx; } static void aptx_quantize_difference(Quantize *quantize, int32_t sample_difference, int32_t dither, int32_t quantization_factor, ConstTables *tables) { const int32_t *intervals = tables->quantize_intervals; int32_t quantized_sample, dithered_sample, parity_change; int32_t d, mean, interval, inv; int64_t error; quantized_sample = aptx_bin_search(FFABS(sample_difference) >> 4, quantization_factor, intervals, tables->tables_size); d = rshift32_clip24(MULH(dither, dither), 7) - (1 << 23); d = rshift64(MUL64(d, tables->quantize_dither_factors[quantized_sample]), 23); intervals += quantized_sample; mean = (intervals[1] + intervals[0]) / 2; interval = (intervals[1] - intervals[0]) * (-(sample_difference < 0) | 1); dithered_sample = rshift64_clip24(MUL64(dither, interval) + ((int64_t)(mean + d) << 32), 32); error = ((int64_t)FFABS(sample_difference) << 20) - MUL64(dithered_sample, quantization_factor); quantize->error = FFABS(rshift64(error, 23)); parity_change = quantized_sample; if (error < 0) quantized_sample--; else parity_change--; inv = -(sample_difference < 0); quantize->quantized_sample = quantized_sample ^ inv; quantize->quantized_sample_parity_change = parity_change ^ inv; } static void aptx_encode_channel(Channel *channel, int32_t samples[4]) { int32_t subband_samples[4]; int subband; aptx_qmf_tree_analysis(&channel->qmf, samples, subband_samples); aptx_generate_dither(channel); for (subband = 0; subband < NB_SUBBANDS; subband++) { int32_t diff = av_clip_intp2(subband_samples[subband] - channel->prediction[subband].predicted_sample, 23); aptx_quantize_difference(&channel->quantize[subband], diff, channel->dither[subband], channel->invert_quantize[subband].quantization_factor, &tables[subband]); } } static void aptx_decode_channel(Channel *channel, int32_t samples[4]) { int32_t subband_samples[4]; int subband; for (subband = 0; subband < NB_SUBBANDS; subband++) subband_samples[subband] = channel->prediction[subband].previous_reconstructed_sample; aptx_qmf_tree_synthesis(&channel->qmf, subband_samples, samples); } static void aptx_invert_quantization(InvertQuantize *invert_quantize, int32_t quantized_sample, int32_t dither, ConstTables *tables) { int32_t qr, idx, shift, factor_select; idx = (quantized_sample ^ -(quantized_sample < 0)) + 1; qr = tables->quantize_intervals[idx] / 2; if (quantized_sample < 0) qr = -qr; qr = rshift64_clip24(((int64_t)qr<<32) + MUL64(dither, tables->invert_quantize_dither_factors[idx]), 32); invert_quantize->reconstructed_difference = MUL64(invert_quantize->quantization_factor, qr) >> 19; shift = 24 - tables->quantized_bits; /* update factor_select */ factor_select = 32620 * invert_quantize->factor_select; factor_select = rshift32(factor_select + (tables->quantize_factor_select_offset[idx] << 15), 15); invert_quantize->factor_select = av_clip(factor_select, 0, (shift << 8) | 0xFF); /* update quantization factor */ idx = (invert_quantize->factor_select & 0xFF) >> 3; shift -= invert_quantize->factor_select >> 8; invert_quantize->quantization_factor = (quantization_factors[idx] << 11) >> shift; } static int32_t *aptx_reconstructed_differences_update(Prediction *prediction, int32_t reconstructed_difference, int order) { int32_t *rd1 = prediction->reconstructed_differences, *rd2 = rd1 + order; int p = prediction->pos; rd1[p] = rd2[p]; prediction->pos = p = (p + 1) % order; rd2[p] = reconstructed_difference; return &rd2[p]; } static void aptx_prediction_filtering(Prediction *prediction, int32_t reconstructed_difference, int order) { int32_t reconstructed_sample, predictor, srd0; int32_t *reconstructed_differences; int64_t predicted_difference = 0; int i; reconstructed_sample = av_clip_intp2(reconstructed_difference + prediction->predicted_sample, 23); predictor = av_clip_intp2((MUL64(prediction->s_weight[0], prediction->previous_reconstructed_sample) + MUL64(prediction->s_weight[1], reconstructed_sample)) >> 22, 23); prediction->previous_reconstructed_sample = reconstructed_sample; reconstructed_differences = aptx_reconstructed_differences_update(prediction, reconstructed_difference, order); srd0 = FFDIFFSIGN(reconstructed_difference, 0) << 23; for (i = 0; i < order; i++) { int32_t srd = FF_SIGNBIT(reconstructed_differences[-i-1]) | 1; prediction->d_weight[i] -= rshift32(prediction->d_weight[i] - srd*srd0, 8); predicted_difference += MUL64(reconstructed_differences[-i], prediction->d_weight[i]); } prediction->predicted_difference = av_clip_intp2(predicted_difference >> 22, 23); prediction->predicted_sample = av_clip_intp2(predictor + prediction->predicted_difference, 23); } static void aptx_process_subband(InvertQuantize *invert_quantize, Prediction *prediction, int32_t quantized_sample, int32_t dither, ConstTables *tables) { int32_t sign, same_sign[2], weight[2], sw1, range; aptx_invert_quantization(invert_quantize, quantized_sample, dither, tables); sign = FFDIFFSIGN(invert_quantize->reconstructed_difference, -prediction->predicted_difference); same_sign[0] = sign * prediction->prev_sign[0]; same_sign[1] = sign * prediction->prev_sign[1]; prediction->prev_sign[0] = prediction->prev_sign[1]; prediction->prev_sign[1] = sign | 1; range = 0x100000; sw1 = rshift32(-same_sign[1] * prediction->s_weight[1], 1); sw1 = (av_clip(sw1, -range, range) & ~0xF) << 4; range = 0x300000; weight[0] = 254 * prediction->s_weight[0] + 0x800000*same_sign[0] + sw1; prediction->s_weight[0] = av_clip(rshift32(weight[0], 8), -range, range); range = 0x3C0000 - prediction->s_weight[0]; weight[1] = 255 * prediction->s_weight[1] + 0xC00000*same_sign[1]; prediction->s_weight[1] = av_clip(rshift32(weight[1], 8), -range, range); aptx_prediction_filtering(prediction, invert_quantize->reconstructed_difference, tables->prediction_order); } static void aptx_invert_quantize_and_prediction(Channel *channel) { int subband; for (subband = 0; subband < NB_SUBBANDS; subband++) aptx_process_subband(&channel->invert_quantize[subband], &channel->prediction[subband], channel->quantize[subband].quantized_sample, channel->dither[subband], &tables[subband]); } static int32_t aptx_quantized_parity(Channel *channel) { int32_t parity = channel->dither_parity; int subband; for (subband = 0; subband < NB_SUBBANDS; subband++) parity ^= channel->quantize[subband].quantized_sample; return parity & 1; } /* For each sample, ensure that the parity of all subbands of all channels * is 0 except once every 8 samples where the parity is forced to 1. */ static int aptx_check_parity(Channel channels[NB_CHANNELS], int32_t *idx) { int32_t parity = aptx_quantized_parity(&channels[LEFT]) ^ aptx_quantized_parity(&channels[RIGHT]); int eighth = *idx == 7; *idx = (*idx + 1) & 7; return parity ^ eighth; } static void aptx_insert_sync(Channel channels[NB_CHANNELS], int32_t *idx) { if (aptx_check_parity(channels, idx)) { int i; Channel *c; static const int map[] = { 1, 2, 0, 3 }; Quantize *min = &channels[NB_CHANNELS-1].quantize[map[0]]; for (c = &channels[NB_CHANNELS-1]; c >= channels; c--) for (i = 0; i < NB_SUBBANDS; i++) if (c->quantize[map[i]].error < min->error) min = &c->quantize[map[i]]; /* Forcing the desired parity is done by offsetting by 1 the quantized * sample from the subband featuring the smallest quantization error. */ min->quantized_sample = min->quantized_sample_parity_change; } } static uint16_t aptx_pack_codeword(Channel *channel) { int32_t parity = aptx_quantized_parity(channel); return (((channel->quantize[3].quantized_sample & 0x06) | parity) << 13) | (((channel->quantize[2].quantized_sample & 0x03) ) << 11) | (((channel->quantize[1].quantized_sample & 0x0F) ) << 7) | (((channel->quantize[0].quantized_sample & 0x7F) ) << 0); } static void aptx_unpack_codeword(Channel *channel, uint16_t codeword) { channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 7); channel->quantize[1].quantized_sample = sign_extend(codeword >> 7, 4); channel->quantize[2].quantized_sample = sign_extend(codeword >> 11, 2); channel->quantize[3].quantized_sample = sign_extend(codeword >> 13, 3); channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1) | aptx_quantized_parity(channel); } static void aptx_encode_samples(AptXContext *ctx, int32_t samples[NB_CHANNELS][4], uint8_t output[2*NB_CHANNELS]) { int channel; for (channel = 0; channel < NB_CHANNELS; channel++) aptx_encode_channel(&ctx->channels[channel], samples[channel]); aptx_insert_sync(ctx->channels, &ctx->sync_idx); for (channel = 0; channel < NB_CHANNELS; channel++) { aptx_invert_quantize_and_prediction(&ctx->channels[channel]); AV_WB16(output + 2*channel, aptx_pack_codeword(&ctx->channels[channel])); } } static int aptx_decode_samples(AptXContext *ctx, const uint8_t input[2*NB_CHANNELS], int32_t samples[NB_CHANNELS][4]) { int channel, ret; for (channel = 0; channel < NB_CHANNELS; channel++) { uint16_t codeword; aptx_generate_dither(&ctx->channels[channel]); codeword = AV_RB16(input + 2*channel); aptx_unpack_codeword(&ctx->channels[channel], codeword); aptx_invert_quantize_and_prediction(&ctx->channels[channel]); } ret = aptx_check_parity(ctx->channels, &ctx->sync_idx); for (channel = 0; channel < NB_CHANNELS; channel++) aptx_decode_channel(&ctx->channels[channel], samples[channel]); return ret; } static av_cold int aptx_init(AVCodecContext *avctx) { AptXContext *s = avctx->priv_data; int chan, subband; if (avctx->frame_size == 0) avctx->frame_size = 1024; if (avctx->frame_size & 3) { av_log(avctx, AV_LOG_ERROR, "Frame size must be a multiple of 4 samples\n"); return AVERROR(EINVAL); } for (chan = 0; chan < NB_CHANNELS; chan++) { Channel *channel = &s->channels[chan]; for (subband = 0; subband < NB_SUBBANDS; subband++) { Prediction *prediction = &channel->prediction[subband]; prediction->prev_sign[0] = 1; prediction->prev_sign[1] = 1; } } ff_af_queue_init(avctx, &s->afq); return 0; } static int aptx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt) { AptXContext *s = avctx->priv_data; AVFrame *frame = data; int pos, channel, sample, ret; if (avpkt->size < 4) { av_log(avctx, AV_LOG_ERROR, "Packet is too small\n"); return AVERROR_INVALIDDATA; } /* get output buffer */ frame->channels = NB_CHANNELS; frame->format = AV_SAMPLE_FMT_S32P; frame->nb_samples = avpkt->size & ~3; if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) return ret; for (pos = 0; pos < frame->nb_samples; pos += 4) { int32_t samples[NB_CHANNELS][4]; if (aptx_decode_samples(s, &avpkt->data[pos], samples)) { av_log(avctx, AV_LOG_ERROR, "Synchronization error\n"); return AVERROR_INVALIDDATA; } for (channel = 0; channel < NB_CHANNELS; channel++) for (sample = 0; sample < 4; sample++) AV_WN32A(&frame->data[channel][4*(sample+pos)], samples[channel][sample] << 8); } *got_frame_ptr = 1; return frame->nb_samples; } static int aptx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr) { AptXContext *s = avctx->priv_data; int pos, channel, sample, ret; if ((ret = ff_af_queue_add(&s->afq, frame)) < 0) return ret; if ((ret = ff_alloc_packet2(avctx, avpkt, frame->nb_samples, 0)) < 0) return ret; for (pos = 0; pos < frame->nb_samples; pos += 4) { int32_t samples[NB_CHANNELS][4]; for (channel = 0; channel < NB_CHANNELS; channel++) for (sample = 0; sample < 4; sample++) samples[channel][sample] = (int32_t)AV_RN32A(&frame->data[channel][4*(sample+pos)]) >> 8; aptx_encode_samples(s, samples, avpkt->data + pos); } ff_af_queue_remove(&s->afq, frame->nb_samples, &avpkt->pts, &avpkt->duration); *got_packet_ptr = 1; return 0; } static av_cold int aptx_close(AVCodecContext *avctx) { AptXContext *s = avctx->priv_data; ff_af_queue_close(&s->afq); return 0; } #if CONFIG_APTX_DECODER AVCodec ff_aptx_decoder = { .name = "aptx", .long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"), .type = AVMEDIA_TYPE_AUDIO, .id = AV_CODEC_ID_APTX, .priv_data_size = sizeof(AptXContext), .init = aptx_init, .decode = aptx_decode_frame, .close = aptx_close, .capabilities = AV_CODEC_CAP_DR1, .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0}, .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P, AV_SAMPLE_FMT_NONE }, }; #endif #if CONFIG_APTX_ENCODER AVCodec ff_aptx_encoder = { .name = "aptx", .long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"), .type = AVMEDIA_TYPE_AUDIO, .id = AV_CODEC_ID_APTX, .priv_data_size = sizeof(AptXContext), .init = aptx_init, .encode2 = aptx_encode_frame, .close = aptx_close, .capabilities = AV_CODEC_CAP_SMALL_LAST_FRAME, .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0}, .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P, AV_SAMPLE_FMT_NONE }, .supported_samplerates = (const int[]) {8000, 16000, 24000, 32000, 44100, 48000, 0}, }; #endif