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 */
36 av_always_inline
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)37 static 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 */
aptx_qmf_tree_analysis(QMFAnalysis * qmf,int32_t samples[4],int32_t subband_samples[4])62 static 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
86 av_always_inline
aptx_bin_search(int32_t value,int32_t factor,const int32_t * intervals,int32_t nb_intervals)87 static 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
aptx_quantize_difference(Quantize * quantize,int32_t sample_difference,int32_t dither,int32_t quantization_factor,ConstTables * tables)100 static 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
aptx_encode_channel(Channel * channel,int32_t samples[4],int hd)140 static 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
aptx_insert_sync(Channel channels[NB_CHANNELS],int32_t * idx)155 static 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
aptx_pack_codeword(Channel * channel)173 static 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
aptxhd_pack_codeword(Channel * channel)182 static 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
aptx_encode_samples(AptXContext * ctx,int32_t samples[NB_CHANNELS][4],uint8_t * output)191 static 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
aptx_encode_frame(AVCodecContext * avctx,AVPacket * avpkt,const AVFrame * frame,int * got_packet_ptr)212 static 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
aptx_close(AVCodecContext * avctx)240 static 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
248 const 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
270 const 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