1/* 2 * Audio Processing Technology codec for Bluetooth (aptX) 3 * 4 * Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org> 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "config_components.h" 24 25#include "libavutil/channel_layout.h" 26#include "aptx.h" 27#include "codec_internal.h" 28#include "encode.h" 29 30/* 31 * Half-band QMF analysis filter realized with a polyphase FIR filter. 32 * Split into 2 subbands and downsample by 2. 33 * So for each pair of samples that goes in, one sample goes out, 34 * split into 2 separate subbands. 35 */ 36av_always_inline 37static void aptx_qmf_polyphase_analysis(FilterSignal signal[NB_FILTERS], 38 const int32_t coeffs[NB_FILTERS][FILTER_TAPS], 39 int shift, 40 int32_t samples[NB_FILTERS], 41 int32_t *low_subband_output, 42 int32_t *high_subband_output) 43{ 44 int32_t subbands[NB_FILTERS]; 45 int i; 46 47 for (i = 0; i < NB_FILTERS; i++) { 48 aptx_qmf_filter_signal_push(&signal[i], samples[NB_FILTERS-1-i]); 49 subbands[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift); 50 } 51 52 *low_subband_output = av_clip_intp2(subbands[0] + subbands[1], 23); 53 *high_subband_output = av_clip_intp2(subbands[0] - subbands[1], 23); 54} 55 56/* 57 * Two stage QMF analysis tree. 58 * Split 4 input samples into 4 subbands and downsample by 4. 59 * So for each group of 4 samples that goes in, one sample goes out, 60 * split into 4 separate subbands. 61 */ 62static void aptx_qmf_tree_analysis(QMFAnalysis *qmf, 63 int32_t samples[4], 64 int32_t subband_samples[4]) 65{ 66 int32_t intermediate_samples[4]; 67 int i; 68 69 /* Split 4 input samples into 2 intermediate subbands downsampled to 2 samples */ 70 for (i = 0; i < 2; i++) 71 aptx_qmf_polyphase_analysis(qmf->outer_filter_signal, 72 aptx_qmf_outer_coeffs, 23, 73 &samples[2*i], 74 &intermediate_samples[0+i], 75 &intermediate_samples[2+i]); 76 77 /* Split 2 intermediate subband samples into 4 final subbands downsampled to 1 sample */ 78 for (i = 0; i < 2; i++) 79 aptx_qmf_polyphase_analysis(qmf->inner_filter_signal[i], 80 aptx_qmf_inner_coeffs, 23, 81 &intermediate_samples[2*i], 82 &subband_samples[2*i+0], 83 &subband_samples[2*i+1]); 84} 85 86av_always_inline 87static int32_t aptx_bin_search(int32_t value, int32_t factor, 88 const int32_t *intervals, int32_t nb_intervals) 89{ 90 int32_t idx = 0; 91 int i; 92 93 for (i = nb_intervals >> 1; i > 0; i >>= 1) 94 if (MUL64(factor, intervals[idx + i]) <= ((int64_t)value << 24)) 95 idx += i; 96 97 return idx; 98} 99 100static void aptx_quantize_difference(Quantize *quantize, 101 int32_t sample_difference, 102 int32_t dither, 103 int32_t quantization_factor, 104 ConstTables *tables) 105{ 106 const int32_t *intervals = tables->quantize_intervals; 107 int32_t quantized_sample, dithered_sample, parity_change; 108 int32_t d, mean, interval, inv, sample_difference_abs; 109 int64_t error; 110 111 sample_difference_abs = FFABS(sample_difference); 112 sample_difference_abs = FFMIN(sample_difference_abs, (1 << 23) - 1); 113 114 quantized_sample = aptx_bin_search(sample_difference_abs >> 4, 115 quantization_factor, 116 intervals, tables->tables_size); 117 118 d = rshift32_clip24(MULH(dither, dither), 7) - (1 << 23); 119 d = rshift64(MUL64(d, tables->quantize_dither_factors[quantized_sample]), 23); 120 121 intervals += quantized_sample; 122 mean = (intervals[1] + intervals[0]) / 2; 123 interval = (intervals[1] - intervals[0]) * (-(sample_difference < 0) | 1); 124 125 dithered_sample = rshift64_clip24(MUL64(dither, interval) + ((int64_t)av_clip_intp2(mean + d, 23) << 32), 32); 126 error = ((int64_t)sample_difference_abs << 20) - MUL64(dithered_sample, quantization_factor); 127 quantize->error = FFABS(rshift64(error, 23)); 128 129 parity_change = quantized_sample; 130 if (error < 0) 131 quantized_sample--; 132 else 133 parity_change--; 134 135 inv = -(sample_difference < 0); 136 quantize->quantized_sample = quantized_sample ^ inv; 137 quantize->quantized_sample_parity_change = parity_change ^ inv; 138} 139 140static void aptx_encode_channel(Channel *channel, int32_t samples[4], int hd) 141{ 142 int32_t subband_samples[4]; 143 int subband; 144 aptx_qmf_tree_analysis(&channel->qmf, samples, subband_samples); 145 ff_aptx_generate_dither(channel); 146 for (subband = 0; subband < NB_SUBBANDS; subband++) { 147 int32_t diff = av_clip_intp2(subband_samples[subband] - channel->prediction[subband].predicted_sample, 23); 148 aptx_quantize_difference(&channel->quantize[subband], diff, 149 channel->dither[subband], 150 channel->invert_quantize[subband].quantization_factor, 151 &ff_aptx_quant_tables[hd][subband]); 152 } 153} 154 155static void aptx_insert_sync(Channel channels[NB_CHANNELS], int32_t *idx) 156{ 157 if (aptx_check_parity(channels, idx)) { 158 int i; 159 Channel *c; 160 static const int map[] = { 1, 2, 0, 3 }; 161 Quantize *min = &channels[NB_CHANNELS-1].quantize[map[0]]; 162 for (c = &channels[NB_CHANNELS-1]; c >= channels; c--) 163 for (i = 0; i < NB_SUBBANDS; i++) 164 if (c->quantize[map[i]].error < min->error) 165 min = &c->quantize[map[i]]; 166 167 /* Forcing the desired parity is done by offsetting by 1 the quantized 168 * sample from the subband featuring the smallest quantization error. */ 169 min->quantized_sample = min->quantized_sample_parity_change; 170 } 171} 172 173static uint16_t aptx_pack_codeword(Channel *channel) 174{ 175 int32_t parity = aptx_quantized_parity(channel); 176 return (((channel->quantize[3].quantized_sample & 0x06) | parity) << 13) 177 | (((channel->quantize[2].quantized_sample & 0x03) ) << 11) 178 | (((channel->quantize[1].quantized_sample & 0x0F) ) << 7) 179 | (((channel->quantize[0].quantized_sample & 0x7F) ) << 0); 180} 181 182static uint32_t aptxhd_pack_codeword(Channel *channel) 183{ 184 int32_t parity = aptx_quantized_parity(channel); 185 return (((channel->quantize[3].quantized_sample & 0x01E) | parity) << 19) 186 | (((channel->quantize[2].quantized_sample & 0x00F) ) << 15) 187 | (((channel->quantize[1].quantized_sample & 0x03F) ) << 9) 188 | (((channel->quantize[0].quantized_sample & 0x1FF) ) << 0); 189} 190 191static void aptx_encode_samples(AptXContext *ctx, 192 int32_t samples[NB_CHANNELS][4], 193 uint8_t *output) 194{ 195 int channel; 196 for (channel = 0; channel < NB_CHANNELS; channel++) 197 aptx_encode_channel(&ctx->channels[channel], samples[channel], ctx->hd); 198 199 aptx_insert_sync(ctx->channels, &ctx->sync_idx); 200 201 for (channel = 0; channel < NB_CHANNELS; channel++) { 202 ff_aptx_invert_quantize_and_prediction(&ctx->channels[channel], ctx->hd); 203 if (ctx->hd) 204 AV_WB24(output + 3*channel, 205 aptxhd_pack_codeword(&ctx->channels[channel])); 206 else 207 AV_WB16(output + 2*channel, 208 aptx_pack_codeword(&ctx->channels[channel])); 209 } 210} 211 212static int aptx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, 213 const AVFrame *frame, int *got_packet_ptr) 214{ 215 AptXContext *s = avctx->priv_data; 216 int pos, ipos, channel, sample, output_size, ret; 217 218 if ((ret = ff_af_queue_add(&s->afq, frame)) < 0) 219 return ret; 220 221 output_size = s->block_size * frame->nb_samples/4; 222 if ((ret = ff_get_encode_buffer(avctx, avpkt, output_size, 0)) < 0) 223 return ret; 224 225 for (pos = 0, ipos = 0; pos < output_size; pos += s->block_size, ipos += 4) { 226 int32_t samples[NB_CHANNELS][4]; 227 228 for (channel = 0; channel < NB_CHANNELS; channel++) 229 for (sample = 0; sample < 4; sample++) 230 samples[channel][sample] = (int32_t)AV_RN32A(&frame->data[channel][4*(ipos+sample)]) >> 8; 231 232 aptx_encode_samples(s, samples, avpkt->data + pos); 233 } 234 235 ff_af_queue_remove(&s->afq, frame->nb_samples, &avpkt->pts, &avpkt->duration); 236 *got_packet_ptr = 1; 237 return 0; 238} 239 240static av_cold int aptx_close(AVCodecContext *avctx) 241{ 242 AptXContext *s = avctx->priv_data; 243 ff_af_queue_close(&s->afq); 244 return 0; 245} 246 247#if CONFIG_APTX_ENCODER 248const FFCodec ff_aptx_encoder = { 249 .p.name = "aptx", 250 .p.long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"), 251 .p.type = AVMEDIA_TYPE_AUDIO, 252 .p.id = AV_CODEC_ID_APTX, 253 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SMALL_LAST_FRAME, 254 .priv_data_size = sizeof(AptXContext), 255 .init = ff_aptx_init, 256 FF_CODEC_ENCODE_CB(aptx_encode_frame), 257 .close = aptx_close, 258 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, 259#if FF_API_OLD_CHANNEL_LAYOUT 260 .p.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0}, 261#endif 262 .p.ch_layouts = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_STEREO, { 0 } }, 263 .p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P, 264 AV_SAMPLE_FMT_NONE }, 265 .p.supported_samplerates = (const int[]) {8000, 16000, 24000, 32000, 44100, 48000, 0}, 266}; 267#endif 268 269#if CONFIG_APTX_HD_ENCODER 270const FFCodec ff_aptx_hd_encoder = { 271 .p.name = "aptx_hd", 272 .p.long_name = NULL_IF_CONFIG_SMALL("aptX HD (Audio Processing Technology for Bluetooth)"), 273 .p.type = AVMEDIA_TYPE_AUDIO, 274 .p.id = AV_CODEC_ID_APTX_HD, 275 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SMALL_LAST_FRAME, 276 .priv_data_size = sizeof(AptXContext), 277 .init = ff_aptx_init, 278 FF_CODEC_ENCODE_CB(aptx_encode_frame), 279 .close = aptx_close, 280 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, 281#if FF_API_OLD_CHANNEL_LAYOUT 282 .p.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0}, 283#endif 284 .p.ch_layouts = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_STEREO, { 0 } }, 285 .p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P, 286 AV_SAMPLE_FMT_NONE }, 287 .p.supported_samplerates = (const int[]) {8000, 16000, 24000, 32000, 44100, 48000, 0}, 288}; 289#endif 290