diff options
author | Aurelien Jacobs <aurel@gnuage.org> | 2017-12-17 21:53:35 +0300 |
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committer | Aurelien Jacobs <aurel@gnuage.org> | 2018-03-08 00:26:53 +0300 |
commit | 4439887198025a9782f2ed52f8fda995269aad07 (patch) | |
tree | dc152252a5996d3530972b441c306863220f1410 /libavcodec/sbcdec.c | |
parent | 0b4ad86959cdd5c53474faf2c0b46e0f8a057fe1 (diff) |
sbc: implement SBC decoder (low-complexity subband codec)
This was originally based on libsbc, and was fully integrated into ffmpeg.
Diffstat (limited to 'libavcodec/sbcdec.c')
-rw-r--r-- | libavcodec/sbcdec.c | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/libavcodec/sbcdec.c b/libavcodec/sbcdec.c new file mode 100644 index 0000000000..be703382ff --- /dev/null +++ b/libavcodec/sbcdec.c @@ -0,0 +1,379 @@ +/* + * Bluetooth low-complexity, subband codec (SBC) + * + * Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org> + * Copyright (C) 2012-2013 Intel Corporation + * Copyright (C) 2008-2010 Nokia Corporation + * Copyright (C) 2004-2010 Marcel Holtmann <marcel@holtmann.org> + * Copyright (C) 2004-2005 Henryk Ploetz <henryk@ploetzli.ch> + * Copyright (C) 2005-2008 Brad Midgley <bmidgley@xmission.com> + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * SBC decoder implementation + */ + +#include <stdbool.h> +#include "avcodec.h" +#include "internal.h" +#include "libavutil/intreadwrite.h" +#include "sbc.h" +#include "sbcdec_data.h" + +struct sbc_decoder_state { + int32_t V[2][170]; + int offset[2][16]; +}; + +typedef struct SBCDecContext { + AVClass *class; + DECLARE_ALIGNED(SBC_ALIGN, struct sbc_frame, frame); + DECLARE_ALIGNED(SBC_ALIGN, struct sbc_decoder_state, dsp); +} SBCDecContext; + +/* + * Unpacks a SBC frame at the beginning of the stream in data, + * which has at most len bytes into frame. + * Returns the length in bytes of the packed frame, or a negative + * value on error. The error codes are: + * + * -1 Data stream too short + * -2 Sync byte incorrect + * -3 CRC8 incorrect + * -4 Bitpool value out of bounds + */ +static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame, + size_t len) +{ + unsigned int consumed; + /* Will copy the parts of the header that are relevant to crc + * calculation here */ + uint8_t crc_header[11] = { 0 }; + int crc_pos; + int32_t temp; + + uint32_t audio_sample; + int ch, sb, blk, bit; /* channel, subband, block and bit standard + counters */ + int bits[2][8]; /* bits distribution */ + uint32_t levels[2][8]; /* levels derived from that */ + + if (len < 4) + return -1; + + if (data[0] == MSBC_SYNCWORD) { + if (data[1] != 0) + return -2; + if (data[2] != 0) + return -2; + + frame->frequency = SBC_FREQ_16000; + frame->blocks = MSBC_BLOCKS; + frame->allocation = LOUDNESS; + frame->mode = MONO; + frame->channels = 1; + frame->subbands = 8; + frame->bitpool = 26; + } else if (data[0] == SBC_SYNCWORD) { + frame->frequency = (data[1] >> 6) & 0x03; + frame->blocks = 4 * ((data[1] >> 4) & 0x03) + 4; + frame->mode = (data[1] >> 2) & 0x03; + frame->channels = frame->mode == MONO ? 1 : 2; + frame->allocation = (data[1] >> 1) & 0x01; + frame->subbands = data[1] & 0x01 ? 8 : 4; + frame->bitpool = data[2]; + + if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) && + frame->bitpool > 16 * frame->subbands) + return -4; + + if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) && + frame->bitpool > 32 * frame->subbands) + return -4; + } else + return -2; + + consumed = 32; + crc_header[0] = data[1]; + crc_header[1] = data[2]; + crc_pos = 16; + + if (frame->mode == JOINT_STEREO) { + if (len * 8 < consumed + frame->subbands) + return -1; + + frame->joint = 0x00; + for (sb = 0; sb < frame->subbands - 1; sb++) + frame->joint |= ((data[4] >> (7 - sb)) & 0x01) << sb; + if (frame->subbands == 4) + crc_header[crc_pos / 8] = data[4] & 0xf0; + else + crc_header[crc_pos / 8] = data[4]; + + consumed += frame->subbands; + crc_pos += frame->subbands; + } + + if (len * 8 < consumed + (4 * frame->subbands * frame->channels)) + return -1; + + for (ch = 0; ch < frame->channels; ch++) { + for (sb = 0; sb < frame->subbands; sb++) { + /* FIXME assert(consumed % 4 == 0); */ + frame->scale_factor[ch][sb] = + (data[consumed >> 3] >> (4 - (consumed & 0x7))) & 0x0F; + crc_header[crc_pos >> 3] |= + frame->scale_factor[ch][sb] << (4 - (crc_pos & 0x7)); + + consumed += 4; + crc_pos += 4; + } + } + + if (data[3] != sbc_crc8(frame->crc_ctx, crc_header, crc_pos)) + return -3; + + ff_sbc_calculate_bits(frame, bits); + + for (ch = 0; ch < frame->channels; ch++) { + for (sb = 0; sb < frame->subbands; sb++) + levels[ch][sb] = (1 << bits[ch][sb]) - 1; + } + + for (blk = 0; blk < frame->blocks; blk++) { + for (ch = 0; ch < frame->channels; ch++) { + for (sb = 0; sb < frame->subbands; sb++) { + uint32_t shift; + + if (levels[ch][sb] == 0) { + frame->sb_sample[blk][ch][sb] = 0; + continue; + } + + shift = frame->scale_factor[ch][sb] + + 1 + SBCDEC_FIXED_EXTRA_BITS; + + audio_sample = 0; + for (bit = 0; bit < bits[ch][sb]; bit++) { + if (consumed > len * 8) + return -1; + + if ((data[consumed >> 3] >> (7 - (consumed & 0x7))) & 0x01) + audio_sample |= 1 << (bits[ch][sb] - bit - 1); + + consumed++; + } + + frame->sb_sample[blk][ch][sb] = (int32_t) + (((((uint64_t) audio_sample << 1) | 1) << shift) / + levels[ch][sb]) - (1 << shift); + } + } + } + + if (frame->mode == JOINT_STEREO) { + for (blk = 0; blk < frame->blocks; blk++) { + for (sb = 0; sb < frame->subbands; sb++) { + if (frame->joint & (0x01 << sb)) { + temp = frame->sb_sample[blk][0][sb] + + frame->sb_sample[blk][1][sb]; + frame->sb_sample[blk][1][sb] = + frame->sb_sample[blk][0][sb] - + frame->sb_sample[blk][1][sb]; + frame->sb_sample[blk][0][sb] = temp; + } + } + } + } + + if ((consumed & 0x7) != 0) + consumed += 8 - (consumed & 0x7); + + return consumed >> 3; +} + +static inline void sbc_synthesize_four(struct sbc_decoder_state *state, + struct sbc_frame *frame, + int ch, int blk, AVFrame *output_frame) +{ + int i, k, idx; + int32_t *v = state->V[ch]; + int *offset = state->offset[ch]; + + for (i = 0; i < 8; i++) { + /* Shifting */ + offset[i]--; + if (offset[i] < 0) { + offset[i] = 79; + memcpy(v + 80, v, 9 * sizeof(*v)); + } + + /* Distribute the new matrix value to the shifted position */ + v[offset[i]] = + ( ff_synmatrix4[i][0] * frame->sb_sample[blk][ch][0] + + ff_synmatrix4[i][1] * frame->sb_sample[blk][ch][1] + + ff_synmatrix4[i][2] * frame->sb_sample[blk][ch][2] + + ff_synmatrix4[i][3] * frame->sb_sample[blk][ch][3] ) >> 15; + } + + /* Compute the samples */ + for (idx = 0, i = 0; i < 4; i++, idx += 5) { + k = (i + 4) & 0xf; + + /* Store in output, Q0 */ + AV_WN16A(&output_frame->data[ch][blk * 8 + i * 2], av_clip_int16( + ( v[offset[i] + 0] * ff_sbc_proto_4_40m0[idx + 0] + + v[offset[k] + 1] * ff_sbc_proto_4_40m1[idx + 0] + + v[offset[i] + 2] * ff_sbc_proto_4_40m0[idx + 1] + + v[offset[k] + 3] * ff_sbc_proto_4_40m1[idx + 1] + + v[offset[i] + 4] * ff_sbc_proto_4_40m0[idx + 2] + + v[offset[k] + 5] * ff_sbc_proto_4_40m1[idx + 2] + + v[offset[i] + 6] * ff_sbc_proto_4_40m0[idx + 3] + + v[offset[k] + 7] * ff_sbc_proto_4_40m1[idx + 3] + + v[offset[i] + 8] * ff_sbc_proto_4_40m0[idx + 4] + + v[offset[k] + 9] * ff_sbc_proto_4_40m1[idx + 4] ) >> 15)); + } +} + +static inline void sbc_synthesize_eight(struct sbc_decoder_state *state, + struct sbc_frame *frame, + int ch, int blk, AVFrame *output_frame) +{ + int i, k, idx; + int32_t *v = state->V[ch]; + int *offset = state->offset[ch]; + + for (i = 0; i < 16; i++) { + /* Shifting */ + offset[i]--; + if (offset[i] < 0) { + offset[i] = 159; + memcpy(v + 160, v, 9 * sizeof(*v)); + } + + /* Distribute the new matrix value to the shifted position */ + v[offset[i]] = + ( ff_synmatrix8[i][0] * frame->sb_sample[blk][ch][0] + + ff_synmatrix8[i][1] * frame->sb_sample[blk][ch][1] + + ff_synmatrix8[i][2] * frame->sb_sample[blk][ch][2] + + ff_synmatrix8[i][3] * frame->sb_sample[blk][ch][3] + + ff_synmatrix8[i][4] * frame->sb_sample[blk][ch][4] + + ff_synmatrix8[i][5] * frame->sb_sample[blk][ch][5] + + ff_synmatrix8[i][6] * frame->sb_sample[blk][ch][6] + + ff_synmatrix8[i][7] * frame->sb_sample[blk][ch][7] ) >> 15; + } + + /* Compute the samples */ + for (idx = 0, i = 0; i < 8; i++, idx += 5) { + k = (i + 8) & 0xf; + + /* Store in output, Q0 */ + AV_WN16A(&output_frame->data[ch][blk * 16 + i * 2], av_clip_int16( + ( v[offset[i] + 0] * ff_sbc_proto_8_80m0[idx + 0] + + v[offset[k] + 1] * ff_sbc_proto_8_80m1[idx + 0] + + v[offset[i] + 2] * ff_sbc_proto_8_80m0[idx + 1] + + v[offset[k] + 3] * ff_sbc_proto_8_80m1[idx + 1] + + v[offset[i] + 4] * ff_sbc_proto_8_80m0[idx + 2] + + v[offset[k] + 5] * ff_sbc_proto_8_80m1[idx + 2] + + v[offset[i] + 6] * ff_sbc_proto_8_80m0[idx + 3] + + v[offset[k] + 7] * ff_sbc_proto_8_80m1[idx + 3] + + v[offset[i] + 8] * ff_sbc_proto_8_80m0[idx + 4] + + v[offset[k] + 9] * ff_sbc_proto_8_80m1[idx + 4] ) >> 15)); + } +} + +static void sbc_synthesize_audio(struct sbc_decoder_state *state, + struct sbc_frame *frame, AVFrame *output_frame) +{ + int ch, blk; + + switch (frame->subbands) { + case 4: + for (ch = 0; ch < frame->channels; ch++) + for (blk = 0; blk < frame->blocks; blk++) + sbc_synthesize_four(state, frame, ch, blk, output_frame); + break; + + case 8: + for (ch = 0; ch < frame->channels; ch++) + for (blk = 0; blk < frame->blocks; blk++) + sbc_synthesize_eight(state, frame, ch, blk, output_frame); + break; + } +} + +static int sbc_decode_init(AVCodecContext *avctx) +{ + SBCDecContext *sbc = avctx->priv_data; + int i, ch; + + sbc->frame.crc_ctx = av_crc_get_table(AV_CRC_8_EBU); + + memset(sbc->dsp.V, 0, sizeof(sbc->dsp.V)); + for (ch = 0; ch < 2; ch++) + for (i = 0; i < FF_ARRAY_ELEMS(sbc->dsp.offset[0]); i++) + sbc->dsp.offset[ch][i] = (10 * i + 10); + return 0; +} + +static int sbc_decode_frame(AVCodecContext *avctx, + void *data, int *got_frame_ptr, + AVPacket *avpkt) +{ + SBCDecContext *sbc = avctx->priv_data; + AVFrame *frame = data; + int ret, frame_length; + + if (!sbc) + return AVERROR(EIO); + + frame_length = sbc_unpack_frame(avpkt->data, &sbc->frame, avpkt->size); + if (frame_length <= 0) + return frame_length; + + frame->channels = sbc->frame.channels; + frame->format = AV_SAMPLE_FMT_S16P; + frame->nb_samples = sbc->frame.blocks * sbc->frame.subbands; + if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) + return ret; + + sbc_synthesize_audio(&sbc->dsp, &sbc->frame, frame); + + *got_frame_ptr = 1; + + return frame_length; +} + +AVCodec ff_sbc_decoder = { + .name = "sbc", + .long_name = NULL_IF_CONFIG_SMALL("SBC (low-complexity subband codec)"), + .type = AVMEDIA_TYPE_AUDIO, + .id = AV_CODEC_ID_SBC, + .priv_data_size = sizeof(SBCDecContext), + .init = sbc_decode_init, + .decode = sbc_decode_frame, + .capabilities = AV_CODEC_CAP_DR1, + .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, + .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO, + AV_CH_LAYOUT_STEREO, 0}, + .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P, + AV_SAMPLE_FMT_NONE }, + .supported_samplerates = (const int[]) { 16000, 32000, 44100, 48000, 0 }, +}; |