2 * Bluetooth low-complexity, subband codec (SBC)
4 * Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org>
5 * Copyright (C) 2012-2013 Intel Corporation
6 * Copyright (C) 2008-2010 Nokia Corporation
7 * Copyright (C) 2004-2010 Marcel Holtmann <marcel@holtmann.org>
8 * Copyright (C) 2004-2005 Henryk Ploetz <henryk@ploetzli.ch>
9 * Copyright (C) 2005-2008 Brad Midgley <bmidgley@xmission.com>
11 * This file is part of FFmpeg.
13 * FFmpeg is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU Lesser General Public
15 * License as published by the Free Software Foundation; either
16 * version 2.1 of the License, or (at your option) any later version.
18 * FFmpeg is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 * Lesser General Public License for more details.
23 * You should have received a copy of the GNU Lesser General Public
24 * License along with FFmpeg; if not, write to the Free Software
25 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30 * SBC decoder implementation
35 #include "libavutil/intreadwrite.h"
37 #include "sbcdec_data.h"
39 struct sbc_decoder_state {
44 typedef struct SBCDecContext {
46 DECLARE_ALIGNED(SBC_ALIGN, struct sbc_frame, frame);
47 DECLARE_ALIGNED(SBC_ALIGN, struct sbc_decoder_state, dsp);
51 * Unpacks a SBC frame at the beginning of the stream in data,
52 * which has at most len bytes into frame.
53 * Returns the length in bytes of the packed frame, or a negative
54 * value on error. The error codes are:
56 * -1 Data stream too short
57 * -2 Sync byte incorrect
59 * -4 Bitpool value out of bounds
61 static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame,
64 unsigned int consumed;
65 /* Will copy the parts of the header that are relevant to crc
67 uint8_t crc_header[11] = { 0 };
71 uint32_t audio_sample;
72 int ch, sb, blk, bit; /* channel, subband, block and bit standard
74 int bits[2][8]; /* bits distribution */
75 uint32_t levels[2][8]; /* levels derived from that */
80 if (data[0] == MSBC_SYNCWORD) {
86 frame->frequency = SBC_FREQ_16000;
87 frame->blocks = MSBC_BLOCKS;
88 frame->allocation = LOUDNESS;
93 } else if (data[0] == SBC_SYNCWORD) {
94 frame->frequency = (data[1] >> 6) & 0x03;
95 frame->blocks = 4 * ((data[1] >> 4) & 0x03) + 4;
96 frame->mode = (data[1] >> 2) & 0x03;
97 frame->channels = frame->mode == MONO ? 1 : 2;
98 frame->allocation = (data[1] >> 1) & 0x01;
99 frame->subbands = data[1] & 0x01 ? 8 : 4;
100 frame->bitpool = data[2];
102 if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) &&
103 frame->bitpool > 16 * frame->subbands)
106 if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) &&
107 frame->bitpool > 32 * frame->subbands)
113 crc_header[0] = data[1];
114 crc_header[1] = data[2];
117 if (frame->mode == JOINT_STEREO) {
118 if (len * 8 < consumed + frame->subbands)
122 for (sb = 0; sb < frame->subbands - 1; sb++)
123 frame->joint |= ((data[4] >> (7 - sb)) & 0x01) << sb;
124 if (frame->subbands == 4)
125 crc_header[crc_pos / 8] = data[4] & 0xf0;
127 crc_header[crc_pos / 8] = data[4];
129 consumed += frame->subbands;
130 crc_pos += frame->subbands;
133 if (len * 8 < consumed + (4 * frame->subbands * frame->channels))
136 for (ch = 0; ch < frame->channels; ch++) {
137 for (sb = 0; sb < frame->subbands; sb++) {
138 /* FIXME assert(consumed % 4 == 0); */
139 frame->scale_factor[ch][sb] =
140 (data[consumed >> 3] >> (4 - (consumed & 0x7))) & 0x0F;
141 crc_header[crc_pos >> 3] |=
142 frame->scale_factor[ch][sb] << (4 - (crc_pos & 0x7));
149 if (data[3] != ff_sbc_crc8(frame->crc_ctx, crc_header, crc_pos))
152 ff_sbc_calculate_bits(frame, bits);
154 for (ch = 0; ch < frame->channels; ch++) {
155 for (sb = 0; sb < frame->subbands; sb++)
156 levels[ch][sb] = (1 << bits[ch][sb]) - 1;
159 for (blk = 0; blk < frame->blocks; blk++) {
160 for (ch = 0; ch < frame->channels; ch++) {
161 for (sb = 0; sb < frame->subbands; sb++) {
164 if (levels[ch][sb] == 0) {
165 frame->sb_sample[blk][ch][sb] = 0;
169 shift = frame->scale_factor[ch][sb] +
170 1 + SBCDEC_FIXED_EXTRA_BITS;
173 for (bit = 0; bit < bits[ch][sb]; bit++) {
174 if (consumed > len * 8)
177 if ((data[consumed >> 3] >> (7 - (consumed & 0x7))) & 0x01)
178 audio_sample |= 1 << (bits[ch][sb] - bit - 1);
183 frame->sb_sample[blk][ch][sb] = (int32_t)
184 (((((uint64_t) audio_sample << 1) | 1) << shift) /
185 levels[ch][sb]) - (1 << shift);
190 if (frame->mode == JOINT_STEREO) {
191 for (blk = 0; blk < frame->blocks; blk++) {
192 for (sb = 0; sb < frame->subbands; sb++) {
193 if (frame->joint & (0x01 << sb)) {
194 temp = frame->sb_sample[blk][0][sb] +
195 frame->sb_sample[blk][1][sb];
196 frame->sb_sample[blk][1][sb] =
197 frame->sb_sample[blk][0][sb] -
198 frame->sb_sample[blk][1][sb];
199 frame->sb_sample[blk][0][sb] = temp;
205 if ((consumed & 0x7) != 0)
206 consumed += 8 - (consumed & 0x7);
208 return consumed >> 3;
211 static inline void sbc_synthesize_four(struct sbc_decoder_state *state,
212 struct sbc_frame *frame,
213 int ch, int blk, AVFrame *output_frame)
216 int32_t *v = state->V[ch];
217 int *offset = state->offset[ch];
219 for (i = 0; i < 8; i++) {
224 memcpy(v + 80, v, 9 * sizeof(*v));
227 /* Distribute the new matrix value to the shifted position */
229 (int)( (unsigned)ff_synmatrix4[i][0] * frame->sb_sample[blk][ch][0] +
230 (unsigned)ff_synmatrix4[i][1] * frame->sb_sample[blk][ch][1] +
231 (unsigned)ff_synmatrix4[i][2] * frame->sb_sample[blk][ch][2] +
232 (unsigned)ff_synmatrix4[i][3] * frame->sb_sample[blk][ch][3] ) >> 15;
235 /* Compute the samples */
236 for (idx = 0, i = 0; i < 4; i++, idx += 5) {
239 /* Store in output, Q0 */
240 AV_WN16A(&output_frame->data[ch][blk * 8 + i * 2], av_clip_int16(
241 (int)( (unsigned)v[offset[i] + 0] * ff_sbc_proto_4_40m0[idx + 0] +
242 (unsigned)v[offset[k] + 1] * ff_sbc_proto_4_40m1[idx + 0] +
243 (unsigned)v[offset[i] + 2] * ff_sbc_proto_4_40m0[idx + 1] +
244 (unsigned)v[offset[k] + 3] * ff_sbc_proto_4_40m1[idx + 1] +
245 (unsigned)v[offset[i] + 4] * ff_sbc_proto_4_40m0[idx + 2] +
246 (unsigned)v[offset[k] + 5] * ff_sbc_proto_4_40m1[idx + 2] +
247 (unsigned)v[offset[i] + 6] * ff_sbc_proto_4_40m0[idx + 3] +
248 (unsigned)v[offset[k] + 7] * ff_sbc_proto_4_40m1[idx + 3] +
249 (unsigned)v[offset[i] + 8] * ff_sbc_proto_4_40m0[idx + 4] +
250 (unsigned)v[offset[k] + 9] * ff_sbc_proto_4_40m1[idx + 4] ) >> 15));
254 static inline void sbc_synthesize_eight(struct sbc_decoder_state *state,
255 struct sbc_frame *frame,
256 int ch, int blk, AVFrame *output_frame)
259 int32_t *v = state->V[ch];
260 int *offset = state->offset[ch];
262 for (i = 0; i < 16; i++) {
267 memcpy(v + 160, v, 9 * sizeof(*v));
270 /* Distribute the new matrix value to the shifted position */
272 (int)( (unsigned)ff_synmatrix8[i][0] * frame->sb_sample[blk][ch][0] +
273 (unsigned)ff_synmatrix8[i][1] * frame->sb_sample[blk][ch][1] +
274 (unsigned)ff_synmatrix8[i][2] * frame->sb_sample[blk][ch][2] +
275 (unsigned)ff_synmatrix8[i][3] * frame->sb_sample[blk][ch][3] +
276 (unsigned)ff_synmatrix8[i][4] * frame->sb_sample[blk][ch][4] +
277 (unsigned)ff_synmatrix8[i][5] * frame->sb_sample[blk][ch][5] +
278 (unsigned)ff_synmatrix8[i][6] * frame->sb_sample[blk][ch][6] +
279 (unsigned)ff_synmatrix8[i][7] * frame->sb_sample[blk][ch][7] ) >> 15;
282 /* Compute the samples */
283 for (idx = 0, i = 0; i < 8; i++, idx += 5) {
286 /* Store in output, Q0 */
287 AV_WN16A(&output_frame->data[ch][blk * 16 + i * 2], av_clip_int16(
288 (int)( (unsigned)v[offset[i] + 0] * ff_sbc_proto_8_80m0[idx + 0] +
289 (unsigned)v[offset[k] + 1] * ff_sbc_proto_8_80m1[idx + 0] +
290 (unsigned)v[offset[i] + 2] * ff_sbc_proto_8_80m0[idx + 1] +
291 (unsigned)v[offset[k] + 3] * ff_sbc_proto_8_80m1[idx + 1] +
292 (unsigned)v[offset[i] + 4] * ff_sbc_proto_8_80m0[idx + 2] +
293 (unsigned)v[offset[k] + 5] * ff_sbc_proto_8_80m1[idx + 2] +
294 (unsigned)v[offset[i] + 6] * ff_sbc_proto_8_80m0[idx + 3] +
295 (unsigned)v[offset[k] + 7] * ff_sbc_proto_8_80m1[idx + 3] +
296 (unsigned)v[offset[i] + 8] * ff_sbc_proto_8_80m0[idx + 4] +
297 (unsigned)v[offset[k] + 9] * ff_sbc_proto_8_80m1[idx + 4] ) >> 15));
301 static void sbc_synthesize_audio(struct sbc_decoder_state *state,
302 struct sbc_frame *frame, AVFrame *output_frame)
306 switch (frame->subbands) {
308 for (ch = 0; ch < frame->channels; ch++)
309 for (blk = 0; blk < frame->blocks; blk++)
310 sbc_synthesize_four(state, frame, ch, blk, output_frame);
314 for (ch = 0; ch < frame->channels; ch++)
315 for (blk = 0; blk < frame->blocks; blk++)
316 sbc_synthesize_eight(state, frame, ch, blk, output_frame);
321 static int sbc_decode_init(AVCodecContext *avctx)
323 SBCDecContext *sbc = avctx->priv_data;
326 avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
328 sbc->frame.crc_ctx = av_crc_get_table(AV_CRC_8_EBU);
330 memset(sbc->dsp.V, 0, sizeof(sbc->dsp.V));
331 for (ch = 0; ch < 2; ch++)
332 for (i = 0; i < FF_ARRAY_ELEMS(sbc->dsp.offset[0]); i++)
333 sbc->dsp.offset[ch][i] = (10 * i + 10);
337 static int sbc_decode_frame(AVCodecContext *avctx,
338 void *data, int *got_frame_ptr,
341 SBCDecContext *sbc = avctx->priv_data;
342 AVFrame *frame = data;
343 int ret, frame_length;
348 frame_length = sbc_unpack_frame(avpkt->data, &sbc->frame, avpkt->size);
349 if (frame_length <= 0)
352 avctx->channels = sbc->frame.channels;
354 frame->nb_samples = sbc->frame.blocks * sbc->frame.subbands;
355 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
358 sbc_synthesize_audio(&sbc->dsp, &sbc->frame, frame);
365 AVCodec ff_sbc_decoder = {
367 .long_name = NULL_IF_CONFIG_SMALL("SBC (low-complexity subband codec)"),
368 .type = AVMEDIA_TYPE_AUDIO,
369 .id = AV_CODEC_ID_SBC,
370 .priv_data_size = sizeof(SBCDecContext),
371 .init = sbc_decode_init,
372 .decode = sbc_decode_frame,
373 .capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
374 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
375 .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
376 AV_CH_LAYOUT_STEREO, 0},
377 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
378 AV_SAMPLE_FMT_NONE },
379 .supported_samplerates = (const int[]) { 16000, 32000, 44100, 48000, 0 },