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/* |
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* Bluetooth low-complexity, subband codec (SBC) |
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* |
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* Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org> |
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* Copyright (C) 2012-2013 Intel Corporation |
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* Copyright (C) 2008-2010 Nokia Corporation |
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* Copyright (C) 2004-2010 Marcel Holtmann <marcel@holtmann.org> |
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* Copyright (C) 2004-2005 Henryk Ploetz <henryk@ploetzli.ch> |
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* Copyright (C) 2005-2008 Brad Midgley <bmidgley@xmission.com> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/** |
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* @file |
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* SBC decoder implementation |
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*/ |
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#include "avcodec.h" |
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#include "internal.h" |
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#include "libavutil/intreadwrite.h" |
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#include "libavutil/mem_internal.h" |
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#include "sbc.h" |
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#include "sbcdec_data.h" |
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struct sbc_decoder_state { |
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int32_t V[2][170]; |
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int offset[2][16]; |
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}; |
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typedef struct SBCDecContext { |
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AVClass *class; |
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DECLARE_ALIGNED(SBC_ALIGN, struct sbc_frame, frame); |
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DECLARE_ALIGNED(SBC_ALIGN, struct sbc_decoder_state, dsp); |
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} SBCDecContext; |
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/* |
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* Unpacks a SBC frame at the beginning of the stream in data, |
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* which has at most len bytes into frame. |
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* Returns the length in bytes of the packed frame, or a negative |
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* value on error. The error codes are: |
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* |
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* -1 Data stream too short |
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* -2 Sync byte incorrect |
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* -3 CRC8 incorrect |
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* -4 Bitpool value out of bounds |
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*/ |
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static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame, |
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size_t len) |
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{ |
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unsigned int consumed; |
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/* Will copy the parts of the header that are relevant to crc |
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* calculation here */ |
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uint8_t crc_header[11] = { 0 }; |
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int crc_pos; |
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int32_t temp; |
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uint32_t audio_sample; |
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int ch, sb, blk, bit; /* channel, subband, block and bit standard |
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counters */ |
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int bits[2][8]; /* bits distribution */ |
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uint32_t levels[2][8]; /* levels derived from that */ |
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if (len < 4) |
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return -1; |
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if (data[0] == MSBC_SYNCWORD) { |
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if (data[1] != 0) |
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return -2; |
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if (data[2] != 0) |
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return -2; |
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frame->frequency = SBC_FREQ_16000; |
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frame->blocks = MSBC_BLOCKS; |
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frame->allocation = LOUDNESS; |
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frame->mode = MONO; |
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frame->channels = 1; |
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frame->subbands = 8; |
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frame->bitpool = 26; |
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} else if (data[0] == SBC_SYNCWORD) { |
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frame->frequency = (data[1] >> 6) & 0x03; |
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frame->blocks = 4 * ((data[1] >> 4) & 0x03) + 4; |
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frame->mode = (data[1] >> 2) & 0x03; |
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frame->channels = frame->mode == MONO ? 1 : 2; |
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frame->allocation = (data[1] >> 1) & 0x01; |
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frame->subbands = data[1] & 0x01 ? 8 : 4; |
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frame->bitpool = data[2]; |
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if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) && |
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frame->bitpool > 16 * frame->subbands) |
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return -4; |
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if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) && |
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frame->bitpool > 32 * frame->subbands) |
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return -4; |
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} else |
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return -2; |
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consumed = 32; |
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crc_header[0] = data[1]; |
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crc_header[1] = data[2]; |
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crc_pos = 16; |
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if (frame->mode == JOINT_STEREO) { |
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if (len * 8 < consumed + frame->subbands) |
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return -1; |
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frame->joint = 0x00; |
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for (sb = 0; sb < frame->subbands - 1; sb++) |
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frame->joint |= ((data[4] >> (7 - sb)) & 0x01) << sb; |
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if (frame->subbands == 4) |
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crc_header[crc_pos / 8] = data[4] & 0xf0; |
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else |
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crc_header[crc_pos / 8] = data[4]; |
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consumed += frame->subbands; |
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crc_pos += frame->subbands; |
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} |
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if (len * 8 < consumed + (4 * frame->subbands * frame->channels)) |
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return -1; |
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for (ch = 0; ch < frame->channels; ch++) { |
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for (sb = 0; sb < frame->subbands; sb++) { |
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/* FIXME assert(consumed % 4 == 0); */ |
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frame->scale_factor[ch][sb] = |
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(data[consumed >> 3] >> (4 - (consumed & 0x7))) & 0x0F; |
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crc_header[crc_pos >> 3] |= |
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frame->scale_factor[ch][sb] << (4 - (crc_pos & 0x7)); |
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consumed += 4; |
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crc_pos += 4; |
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} |
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} |
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if (data[3] != ff_sbc_crc8(frame->crc_ctx, crc_header, crc_pos)) |
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return -3; |
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ff_sbc_calculate_bits(frame, bits); |
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for (ch = 0; ch < frame->channels; ch++) { |
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for (sb = 0; sb < frame->subbands; sb++) |
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levels[ch][sb] = (1 << bits[ch][sb]) - 1; |
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} |
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160 |
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for (blk = 0; blk < frame->blocks; blk++) { |
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for (ch = 0; ch < frame->channels; ch++) { |
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for (sb = 0; sb < frame->subbands; sb++) { |
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uint32_t shift; |
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if (levels[ch][sb] == 0) { |
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frame->sb_sample[blk][ch][sb] = 0; |
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continue; |
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} |
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shift = frame->scale_factor[ch][sb] + |
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1 + SBCDEC_FIXED_EXTRA_BITS; |
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audio_sample = 0; |
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for (bit = 0; bit < bits[ch][sb]; bit++) { |
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if (consumed > len * 8) |
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return -1; |
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if ((data[consumed >> 3] >> (7 - (consumed & 0x7))) & 0x01) |
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audio_sample |= 1 << (bits[ch][sb] - bit - 1); |
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consumed++; |
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} |
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frame->sb_sample[blk][ch][sb] = (int32_t) |
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(((((uint64_t) audio_sample << 1) | 1) << shift) / |
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levels[ch][sb]) - (1 << shift); |
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} |
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} |
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} |
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if (frame->mode == JOINT_STEREO) { |
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for (blk = 0; blk < frame->blocks; blk++) { |
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for (sb = 0; sb < frame->subbands; sb++) { |
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if (frame->joint & (0x01 << sb)) { |
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temp = frame->sb_sample[blk][0][sb] + |
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frame->sb_sample[blk][1][sb]; |
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frame->sb_sample[blk][1][sb] = |
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frame->sb_sample[blk][0][sb] - |
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frame->sb_sample[blk][1][sb]; |
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frame->sb_sample[blk][0][sb] = temp; |
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} |
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} |
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} |
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} |
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if ((consumed & 0x7) != 0) |
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consumed += 8 - (consumed & 0x7); |
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return consumed >> 3; |
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} |
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static inline void sbc_synthesize_four(struct sbc_decoder_state *state, |
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struct sbc_frame *frame, |
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int ch, int blk, AVFrame *output_frame) |
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{ |
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int i, k, idx; |
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int32_t *v = state->V[ch]; |
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int *offset = state->offset[ch]; |
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for (i = 0; i < 8; i++) { |
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/* Shifting */ |
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offset[i]--; |
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if (offset[i] < 0) { |
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offset[i] = 79; |
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memcpy(v + 80, v, 9 * sizeof(*v)); |
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} |
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/* Distribute the new matrix value to the shifted position */ |
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v[offset[i]] = |
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(int)( (unsigned)ff_synmatrix4[i][0] * frame->sb_sample[blk][ch][0] + |
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(unsigned)ff_synmatrix4[i][1] * frame->sb_sample[blk][ch][1] + |
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(unsigned)ff_synmatrix4[i][2] * frame->sb_sample[blk][ch][2] + |
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(unsigned)ff_synmatrix4[i][3] * frame->sb_sample[blk][ch][3] ) >> 15; |
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} |
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/* Compute the samples */ |
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for (idx = 0, i = 0; i < 4; i++, idx += 5) { |
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k = (i + 4) & 0xf; |
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/* Store in output, Q0 */ |
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AV_WN16A(&output_frame->data[ch][blk * 8 + i * 2], av_clip_int16( |
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(int)( (unsigned)v[offset[i] + 0] * ff_sbc_proto_4_40m0[idx + 0] + |
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(unsigned)v[offset[k] + 1] * ff_sbc_proto_4_40m1[idx + 0] + |
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(unsigned)v[offset[i] + 2] * ff_sbc_proto_4_40m0[idx + 1] + |
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(unsigned)v[offset[k] + 3] * ff_sbc_proto_4_40m1[idx + 1] + |
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(unsigned)v[offset[i] + 4] * ff_sbc_proto_4_40m0[idx + 2] + |
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(unsigned)v[offset[k] + 5] * ff_sbc_proto_4_40m1[idx + 2] + |
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(unsigned)v[offset[i] + 6] * ff_sbc_proto_4_40m0[idx + 3] + |
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(unsigned)v[offset[k] + 7] * ff_sbc_proto_4_40m1[idx + 3] + |
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(unsigned)v[offset[i] + 8] * ff_sbc_proto_4_40m0[idx + 4] + |
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(unsigned)v[offset[k] + 9] * ff_sbc_proto_4_40m1[idx + 4] ) >> 15)); |
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} |
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} |
254 |
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static inline void sbc_synthesize_eight(struct sbc_decoder_state *state, |
256 |
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struct sbc_frame *frame, |
257 |
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int ch, int blk, AVFrame *output_frame) |
258 |
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{ |
259 |
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int i, k, idx; |
260 |
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int32_t *v = state->V[ch]; |
261 |
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int *offset = state->offset[ch]; |
262 |
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263 |
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for (i = 0; i < 16; i++) { |
264 |
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/* Shifting */ |
265 |
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offset[i]--; |
266 |
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if (offset[i] < 0) { |
267 |
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offset[i] = 159; |
268 |
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memcpy(v + 160, v, 9 * sizeof(*v)); |
269 |
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} |
270 |
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271 |
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/* Distribute the new matrix value to the shifted position */ |
272 |
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v[offset[i]] = |
273 |
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(int)( (unsigned)ff_synmatrix8[i][0] * frame->sb_sample[blk][ch][0] + |
274 |
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(unsigned)ff_synmatrix8[i][1] * frame->sb_sample[blk][ch][1] + |
275 |
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(unsigned)ff_synmatrix8[i][2] * frame->sb_sample[blk][ch][2] + |
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(unsigned)ff_synmatrix8[i][3] * frame->sb_sample[blk][ch][3] + |
277 |
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(unsigned)ff_synmatrix8[i][4] * frame->sb_sample[blk][ch][4] + |
278 |
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(unsigned)ff_synmatrix8[i][5] * frame->sb_sample[blk][ch][5] + |
279 |
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(unsigned)ff_synmatrix8[i][6] * frame->sb_sample[blk][ch][6] + |
280 |
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(unsigned)ff_synmatrix8[i][7] * frame->sb_sample[blk][ch][7] ) >> 15; |
281 |
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} |
282 |
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283 |
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/* Compute the samples */ |
284 |
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for (idx = 0, i = 0; i < 8; i++, idx += 5) { |
285 |
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k = (i + 8) & 0xf; |
286 |
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287 |
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/* Store in output, Q0 */ |
288 |
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AV_WN16A(&output_frame->data[ch][blk * 16 + i * 2], av_clip_int16( |
289 |
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(int)( (unsigned)v[offset[i] + 0] * ff_sbc_proto_8_80m0[idx + 0] + |
290 |
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(unsigned)v[offset[k] + 1] * ff_sbc_proto_8_80m1[idx + 0] + |
291 |
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(unsigned)v[offset[i] + 2] * ff_sbc_proto_8_80m0[idx + 1] + |
292 |
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(unsigned)v[offset[k] + 3] * ff_sbc_proto_8_80m1[idx + 1] + |
293 |
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(unsigned)v[offset[i] + 4] * ff_sbc_proto_8_80m0[idx + 2] + |
294 |
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(unsigned)v[offset[k] + 5] * ff_sbc_proto_8_80m1[idx + 2] + |
295 |
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(unsigned)v[offset[i] + 6] * ff_sbc_proto_8_80m0[idx + 3] + |
296 |
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(unsigned)v[offset[k] + 7] * ff_sbc_proto_8_80m1[idx + 3] + |
297 |
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(unsigned)v[offset[i] + 8] * ff_sbc_proto_8_80m0[idx + 4] + |
298 |
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(unsigned)v[offset[k] + 9] * ff_sbc_proto_8_80m1[idx + 4] ) >> 15)); |
299 |
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} |
300 |
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} |
301 |
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302 |
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static void sbc_synthesize_audio(struct sbc_decoder_state *state, |
303 |
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struct sbc_frame *frame, AVFrame *output_frame) |
304 |
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{ |
305 |
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int ch, blk; |
306 |
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307 |
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switch (frame->subbands) { |
308 |
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case 4: |
309 |
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for (ch = 0; ch < frame->channels; ch++) |
310 |
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for (blk = 0; blk < frame->blocks; blk++) |
311 |
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sbc_synthesize_four(state, frame, ch, blk, output_frame); |
312 |
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break; |
313 |
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314 |
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case 8: |
315 |
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for (ch = 0; ch < frame->channels; ch++) |
316 |
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for (blk = 0; blk < frame->blocks; blk++) |
317 |
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sbc_synthesize_eight(state, frame, ch, blk, output_frame); |
318 |
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break; |
319 |
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} |
320 |
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} |
321 |
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322 |
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static int sbc_decode_init(AVCodecContext *avctx) |
323 |
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{ |
324 |
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SBCDecContext *sbc = avctx->priv_data; |
325 |
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int i, ch; |
326 |
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327 |
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avctx->sample_fmt = AV_SAMPLE_FMT_S16P; |
328 |
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329 |
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sbc->frame.crc_ctx = av_crc_get_table(AV_CRC_8_EBU); |
330 |
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331 |
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memset(sbc->dsp.V, 0, sizeof(sbc->dsp.V)); |
332 |
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for (ch = 0; ch < 2; ch++) |
333 |
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for (i = 0; i < FF_ARRAY_ELEMS(sbc->dsp.offset[0]); i++) |
334 |
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sbc->dsp.offset[ch][i] = (10 * i + 10); |
335 |
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return 0; |
336 |
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} |
337 |
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|
338 |
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static int sbc_decode_frame(AVCodecContext *avctx, |
339 |
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void *data, int *got_frame_ptr, |
340 |
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AVPacket *avpkt) |
341 |
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{ |
342 |
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SBCDecContext *sbc = avctx->priv_data; |
343 |
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AVFrame *frame = data; |
344 |
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int ret, frame_length; |
345 |
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346 |
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if (!sbc) |
347 |
|
|
return AVERROR(EIO); |
348 |
|
|
|
349 |
|
|
frame_length = sbc_unpack_frame(avpkt->data, &sbc->frame, avpkt->size); |
350 |
|
|
if (frame_length <= 0) |
351 |
|
|
return frame_length; |
352 |
|
|
|
353 |
|
|
avctx->channels = sbc->frame.channels; |
354 |
|
|
|
355 |
|
|
frame->nb_samples = sbc->frame.blocks * sbc->frame.subbands; |
356 |
|
|
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
357 |
|
|
return ret; |
358 |
|
|
|
359 |
|
|
sbc_synthesize_audio(&sbc->dsp, &sbc->frame, frame); |
360 |
|
|
|
361 |
|
|
*got_frame_ptr = 1; |
362 |
|
|
|
363 |
|
|
return frame_length; |
364 |
|
|
} |
365 |
|
|
|
366 |
|
|
AVCodec ff_sbc_decoder = { |
367 |
|
|
.name = "sbc", |
368 |
|
|
.long_name = NULL_IF_CONFIG_SMALL("SBC (low-complexity subband codec)"), |
369 |
|
|
.type = AVMEDIA_TYPE_AUDIO, |
370 |
|
|
.id = AV_CODEC_ID_SBC, |
371 |
|
|
.priv_data_size = sizeof(SBCDecContext), |
372 |
|
|
.init = sbc_decode_init, |
373 |
|
|
.decode = sbc_decode_frame, |
374 |
|
|
.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF, |
375 |
|
|
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, |
376 |
|
|
.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO, |
377 |
|
|
AV_CH_LAYOUT_STEREO, 0}, |
378 |
|
|
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P, |
379 |
|
|
AV_SAMPLE_FMT_NONE }, |
380 |
|
|
.supported_samplerates = (const int[]) { 16000, 32000, 44100, 48000, 0 }, |
381 |
|
|
}; |