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 "internal.h"
29
30 /*
31 * Half-band QMF synthesis filter realized with a polyphase FIR filter.
32 * Join 2 subbands and upsample by 2.
33 * So for each 2 subbands sample that goes in, a pair of samples goes out.
34 */
35 av_always_inline
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])36 static void aptx_qmf_polyphase_synthesis(FilterSignal signal[NB_FILTERS],
37 const int32_t coeffs[NB_FILTERS][FILTER_TAPS],
38 int shift,
39 int32_t low_subband_input,
40 int32_t high_subband_input,
41 int32_t samples[NB_FILTERS])
42 {
43 int32_t subbands[NB_FILTERS];
44 int i;
45
46 subbands[0] = low_subband_input + high_subband_input;
47 subbands[1] = low_subband_input - high_subband_input;
48
49 for (i = 0; i < NB_FILTERS; i++) {
50 aptx_qmf_filter_signal_push(&signal[i], subbands[1-i]);
51 samples[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift);
52 }
53 }
54
55 /*
56 * Two stage QMF synthesis tree.
57 * Join 4 subbands and upsample by 4.
58 * So for each 4 subbands sample that goes in, a group of 4 samples goes out.
59 */
aptx_qmf_tree_synthesis(QMFAnalysis *qmf, int32_t subband_samples[4], int32_t samples[4])60 static void aptx_qmf_tree_synthesis(QMFAnalysis *qmf,
61 int32_t subband_samples[4],
62 int32_t samples[4])
63 {
64 int32_t intermediate_samples[4];
65 int i;
66
67 /* Join 4 subbands into 2 intermediate subbands upsampled to 2 samples. */
68 for (i = 0; i < 2; i++)
69 aptx_qmf_polyphase_synthesis(qmf->inner_filter_signal[i],
70 aptx_qmf_inner_coeffs, 22,
71 subband_samples[2*i+0],
72 subband_samples[2*i+1],
73 &intermediate_samples[2*i]);
74
75 /* Join 2 samples from intermediate subbands upsampled to 4 samples. */
76 for (i = 0; i < 2; i++)
77 aptx_qmf_polyphase_synthesis(qmf->outer_filter_signal,
78 aptx_qmf_outer_coeffs, 21,
79 intermediate_samples[0+i],
80 intermediate_samples[2+i],
81 &samples[2*i]);
82 }
83
84
aptx_decode_channel(Channel *channel, int32_t samples[4])85 static void aptx_decode_channel(Channel *channel, int32_t samples[4])
86 {
87 int32_t subband_samples[4];
88 int subband;
89 for (subband = 0; subband < NB_SUBBANDS; subband++)
90 subband_samples[subband] = channel->prediction[subband].previous_reconstructed_sample;
91 aptx_qmf_tree_synthesis(&channel->qmf, subband_samples, samples);
92 }
93
aptx_unpack_codeword(Channel *channel, uint16_t codeword)94 static void aptx_unpack_codeword(Channel *channel, uint16_t codeword)
95 {
96 channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 7);
97 channel->quantize[1].quantized_sample = sign_extend(codeword >> 7, 4);
98 channel->quantize[2].quantized_sample = sign_extend(codeword >> 11, 2);
99 channel->quantize[3].quantized_sample = sign_extend(codeword >> 13, 3);
100 channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
101 | aptx_quantized_parity(channel);
102 }
103
aptxhd_unpack_codeword(Channel *channel, uint32_t codeword)104 static void aptxhd_unpack_codeword(Channel *channel, uint32_t codeword)
105 {
106 channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 9);
107 channel->quantize[1].quantized_sample = sign_extend(codeword >> 9, 6);
108 channel->quantize[2].quantized_sample = sign_extend(codeword >> 15, 4);
109 channel->quantize[3].quantized_sample = sign_extend(codeword >> 19, 5);
110 channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
111 | aptx_quantized_parity(channel);
112 }
113
aptx_decode_samples(AptXContext *ctx, const uint8_t *input, int32_t samples[NB_CHANNELS][4])114 static int aptx_decode_samples(AptXContext *ctx,
115 const uint8_t *input,
116 int32_t samples[NB_CHANNELS][4])
117 {
118 int channel, ret;
119
120 for (channel = 0; channel < NB_CHANNELS; channel++) {
121 ff_aptx_generate_dither(&ctx->channels[channel]);
122
123 if (ctx->hd)
124 aptxhd_unpack_codeword(&ctx->channels[channel],
125 AV_RB24(input + 3*channel));
126 else
127 aptx_unpack_codeword(&ctx->channels[channel],
128 AV_RB16(input + 2*channel));
129 ff_aptx_invert_quantize_and_prediction(&ctx->channels[channel], ctx->hd);
130 }
131
132 ret = aptx_check_parity(ctx->channels, &ctx->sync_idx);
133
134 for (channel = 0; channel < NB_CHANNELS; channel++)
135 aptx_decode_channel(&ctx->channels[channel], samples[channel]);
136
137 return ret;
138 }
139
aptx_decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame_ptr, AVPacket *avpkt)140 static int aptx_decode_frame(AVCodecContext *avctx, AVFrame *frame,
141 int *got_frame_ptr, AVPacket *avpkt)
142 {
143 AptXContext *s = avctx->priv_data;
144 int pos, opos, channel, sample, ret;
145
146 if (avpkt->size < s->block_size) {
147 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
148 return AVERROR_INVALIDDATA;
149 }
150
151 /* get output buffer */
152 frame->ch_layout.nb_channels = NB_CHANNELS;
153 frame->format = AV_SAMPLE_FMT_S32P;
154 frame->nb_samples = 4 * avpkt->size / s->block_size;
155 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
156 return ret;
157
158 for (pos = 0, opos = 0; opos < frame->nb_samples; pos += s->block_size, opos += 4) {
159 int32_t samples[NB_CHANNELS][4];
160
161 if (aptx_decode_samples(s, &avpkt->data[pos], samples)) {
162 av_log(avctx, AV_LOG_ERROR, "Synchronization error\n");
163 return AVERROR_INVALIDDATA;
164 }
165
166 for (channel = 0; channel < NB_CHANNELS; channel++)
167 for (sample = 0; sample < 4; sample++)
168 AV_WN32A(&frame->data[channel][4*(opos+sample)],
169 samples[channel][sample] * 256);
170 }
171
172 *got_frame_ptr = 1;
173 return s->block_size * frame->nb_samples / 4;
174 }
175
176 #if CONFIG_APTX_DECODER
177 const FFCodec ff_aptx_decoder = {
178 .p.name = "aptx",
179 .p.long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"),
180 .p.type = AVMEDIA_TYPE_AUDIO,
181 .p.id = AV_CODEC_ID_APTX,
182 .priv_data_size = sizeof(AptXContext),
183 .init = ff_aptx_init,
184 FF_CODEC_DECODE_CB(aptx_decode_frame),
185 .p.capabilities = AV_CODEC_CAP_DR1,
186 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
187 #if FF_API_OLD_CHANNEL_LAYOUT
188 .p.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
189 #endif
190 .p.ch_layouts = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_STEREO, { 0 } },
191 .p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
192 AV_SAMPLE_FMT_NONE },
193 };
194 #endif
195
196 #if CONFIG_APTX_HD_DECODER
197 const FFCodec ff_aptx_hd_decoder = {
198 .p.name = "aptx_hd",
199 .p.long_name = NULL_IF_CONFIG_SMALL("aptX HD (Audio Processing Technology for Bluetooth)"),
200 .p.type = AVMEDIA_TYPE_AUDIO,
201 .p.id = AV_CODEC_ID_APTX_HD,
202 .priv_data_size = sizeof(AptXContext),
203 .init = ff_aptx_init,
204 FF_CODEC_DECODE_CB(aptx_decode_frame),
205 .p.capabilities = AV_CODEC_CAP_DR1,
206 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
207 #if FF_API_OLD_CHANNEL_LAYOUT
208 .p.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
209 #endif
210 .p.ch_layouts = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_STEREO, { 0 } },
211 .p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
212 AV_SAMPLE_FMT_NONE },
213 };
214 #endif
215