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FFmpeg/libavcodec/sbcdec.c
Andreas Rheinhardt a247ac640d avcodec: Constify AVCodecs 
Given that the AVCodec.next pointer has now been removed, most of the
AVCodecs are not modified at all any more and can therefore be made
const (as this patch does); the only exceptions are the very few codecs
for external libraries that have a init_static_data callback.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2021-04-27 10:43:15 -03:00

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/*
* 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 "avcodec.h"
#include "internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem_internal.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] != ff_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]] =
(int)( (unsigned)ff_synmatrix4[i][0] * frame->sb_sample[blk][ch][0] +
(unsigned)ff_synmatrix4[i][1] * frame->sb_sample[blk][ch][1] +
(unsigned)ff_synmatrix4[i][2] * frame->sb_sample[blk][ch][2] +
(unsigned)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(
(int)( (unsigned)v[offset[i] + 0] * ff_sbc_proto_4_40m0[idx + 0] +
(unsigned)v[offset[k] + 1] * ff_sbc_proto_4_40m1[idx + 0] +
(unsigned)v[offset[i] + 2] * ff_sbc_proto_4_40m0[idx + 1] +
(unsigned)v[offset[k] + 3] * ff_sbc_proto_4_40m1[idx + 1] +
(unsigned)v[offset[i] + 4] * ff_sbc_proto_4_40m0[idx + 2] +
(unsigned)v[offset[k] + 5] * ff_sbc_proto_4_40m1[idx + 2] +
(unsigned)v[offset[i] + 6] * ff_sbc_proto_4_40m0[idx + 3] +
(unsigned)v[offset[k] + 7] * ff_sbc_proto_4_40m1[idx + 3] +
(unsigned)v[offset[i] + 8] * ff_sbc_proto_4_40m0[idx + 4] +
(unsigned)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]] =
(int)( (unsigned)ff_synmatrix8[i][0] * frame->sb_sample[blk][ch][0] +
(unsigned)ff_synmatrix8[i][1] * frame->sb_sample[blk][ch][1] +
(unsigned)ff_synmatrix8[i][2] * frame->sb_sample[blk][ch][2] +
(unsigned)ff_synmatrix8[i][3] * frame->sb_sample[blk][ch][3] +
(unsigned)ff_synmatrix8[i][4] * frame->sb_sample[blk][ch][4] +
(unsigned)ff_synmatrix8[i][5] * frame->sb_sample[blk][ch][5] +
(unsigned)ff_synmatrix8[i][6] * frame->sb_sample[blk][ch][6] +
(unsigned)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(
(int)( (unsigned)v[offset[i] + 0] * ff_sbc_proto_8_80m0[idx + 0] +
(unsigned)v[offset[k] + 1] * ff_sbc_proto_8_80m1[idx + 0] +
(unsigned)v[offset[i] + 2] * ff_sbc_proto_8_80m0[idx + 1] +
(unsigned)v[offset[k] + 3] * ff_sbc_proto_8_80m1[idx + 1] +
(unsigned)v[offset[i] + 4] * ff_sbc_proto_8_80m0[idx + 2] +
(unsigned)v[offset[k] + 5] * ff_sbc_proto_8_80m1[idx + 2] +
(unsigned)v[offset[i] + 6] * ff_sbc_proto_8_80m0[idx + 3] +
(unsigned)v[offset[k] + 7] * ff_sbc_proto_8_80m1[idx + 3] +
(unsigned)v[offset[i] + 8] * ff_sbc_proto_8_80m0[idx + 4] +
(unsigned)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;
avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
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;
avctx->channels = sbc->frame.channels;
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;
}
const 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 | AV_CODEC_CAP_CHANNEL_CONF,
.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 },
};
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