summaryrefslogtreecommitdiff
path: root/libavcodec/sbc.c
diff options
context:
space:
mode:
Diffstat (limited to 'libavcodec/sbc.c')
-rw-r--r--libavcodec/sbc.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/libavcodec/sbc.c b/libavcodec/sbc.c
new file mode 100644
index 0000000000..b43b66e3f5
--- /dev/null
+++ b/libavcodec/sbc.c
@@ -0,0 +1,271 @@
+/*
+ * 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 common functions for the encoder and decoder
+ */
+
+#include "avcodec.h"
+#include "sbc.h"
+
+/* A2DP specification: Appendix B, page 69 */
+static const int sbc_offset4[4][4] = {
+ { -1, 0, 0, 0 },
+ { -2, 0, 0, 1 },
+ { -2, 0, 0, 1 },
+ { -2, 0, 0, 1 }
+};
+
+/* A2DP specification: Appendix B, page 69 */
+static const int sbc_offset8[4][8] = {
+ { -2, 0, 0, 0, 0, 0, 0, 1 },
+ { -3, 0, 0, 0, 0, 0, 1, 2 },
+ { -4, 0, 0, 0, 0, 0, 1, 2 },
+ { -4, 0, 0, 0, 0, 0, 1, 2 }
+};
+
+/*
+ * Calculates the CRC-8 of the first len bits in data
+ */
+uint8_t ff_sbc_crc8(const AVCRC *ctx, const uint8_t *data, size_t len)
+{
+ size_t byte_length = len >> 3;
+ int bit_length = len & 7;
+ uint8_t crc;
+
+ crc = av_crc(ctx, 0x0F, data, byte_length);
+
+ if (bit_length) {
+ uint8_t bits = data[byte_length];
+ while (bit_length--) {
+ int8_t mask = bits ^ crc;
+ crc = (crc << 1) ^ ((mask >> 7) & 0x1D);
+ bits <<= 1;
+ }
+ }
+
+ return crc;
+}
+
+/*
+ * Code straight from the spec to calculate the bits array
+ * Takes a pointer to the frame in question and a pointer to the bits array
+ */
+void ff_sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8])
+{
+ int subbands = frame->subbands;
+ uint8_t sf = frame->frequency;
+
+ if (frame->mode == MONO || frame->mode == DUAL_CHANNEL) {
+ int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
+ int ch, sb;
+
+ for (ch = 0; ch < frame->channels; ch++) {
+ max_bitneed = 0;
+ if (frame->allocation == SNR) {
+ for (sb = 0; sb < subbands; sb++) {
+ bitneed[ch][sb] = frame->scale_factor[ch][sb];
+ if (bitneed[ch][sb] > max_bitneed)
+ max_bitneed = bitneed[ch][sb];
+ }
+ } else {
+ for (sb = 0; sb < subbands; sb++) {
+ if (frame->scale_factor[ch][sb] == 0)
+ bitneed[ch][sb] = -5;
+ else {
+ if (subbands == 4)
+ loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];
+ else
+ loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb];
+ if (loudness > 0)
+ bitneed[ch][sb] = loudness / 2;
+ else
+ bitneed[ch][sb] = loudness;
+ }
+ if (bitneed[ch][sb] > max_bitneed)
+ max_bitneed = bitneed[ch][sb];
+ }
+ }
+
+ bitcount = 0;
+ slicecount = 0;
+ bitslice = max_bitneed + 1;
+ do {
+ bitslice--;
+ bitcount += slicecount;
+ slicecount = 0;
+ for (sb = 0; sb < subbands; sb++) {
+ if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16))
+ slicecount++;
+ else if (bitneed[ch][sb] == bitslice + 1)
+ slicecount += 2;
+ }
+ } while (bitcount + slicecount < frame->bitpool);
+
+ if (bitcount + slicecount == frame->bitpool) {
+ bitcount += slicecount;
+ bitslice--;
+ }
+
+ for (sb = 0; sb < subbands; sb++) {
+ if (bitneed[ch][sb] < bitslice + 2)
+ bits[ch][sb] = 0;
+ else {
+ bits[ch][sb] = bitneed[ch][sb] - bitslice;
+ if (bits[ch][sb] > 16)
+ bits[ch][sb] = 16;
+ }
+ }
+
+ for (sb = 0; bitcount < frame->bitpool &&
+ sb < subbands; sb++) {
+ if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) {
+ bits[ch][sb]++;
+ bitcount++;
+ } else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) {
+ bits[ch][sb] = 2;
+ bitcount += 2;
+ }
+ }
+
+ for (sb = 0; bitcount < frame->bitpool &&
+ sb < subbands; sb++) {
+ if (bits[ch][sb] < 16) {
+ bits[ch][sb]++;
+ bitcount++;
+ }
+ }
+
+ }
+
+ } else if (frame->mode == STEREO || frame->mode == JOINT_STEREO) {
+ int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
+ int ch, sb;
+
+ max_bitneed = 0;
+ if (frame->allocation == SNR) {
+ for (ch = 0; ch < 2; ch++) {
+ for (sb = 0; sb < subbands; sb++) {
+ bitneed[ch][sb] = frame->scale_factor[ch][sb];
+ if (bitneed[ch][sb] > max_bitneed)
+ max_bitneed = bitneed[ch][sb];
+ }
+ }
+ } else {
+ for (ch = 0; ch < 2; ch++) {
+ for (sb = 0; sb < subbands; sb++) {
+ if (frame->scale_factor[ch][sb] == 0)
+ bitneed[ch][sb] = -5;
+ else {
+ if (subbands == 4)
+ loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];
+ else
+ loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb];
+ if (loudness > 0)
+ bitneed[ch][sb] = loudness / 2;
+ else
+ bitneed[ch][sb] = loudness;
+ }
+ if (bitneed[ch][sb] > max_bitneed)
+ max_bitneed = bitneed[ch][sb];
+ }
+ }
+ }
+
+ bitcount = 0;
+ slicecount = 0;
+ bitslice = max_bitneed + 1;
+ do {
+ bitslice--;
+ bitcount += slicecount;
+ slicecount = 0;
+ for (ch = 0; ch < 2; ch++) {
+ for (sb = 0; sb < subbands; sb++) {
+ if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16))
+ slicecount++;
+ else if (bitneed[ch][sb] == bitslice + 1)
+ slicecount += 2;
+ }
+ }
+ } while (bitcount + slicecount < frame->bitpool);
+
+ if (bitcount + slicecount == frame->bitpool) {
+ bitcount += slicecount;
+ bitslice--;
+ }
+
+ for (ch = 0; ch < 2; ch++) {
+ for (sb = 0; sb < subbands; sb++) {
+ if (bitneed[ch][sb] < bitslice + 2) {
+ bits[ch][sb] = 0;
+ } else {
+ bits[ch][sb] = bitneed[ch][sb] - bitslice;
+ if (bits[ch][sb] > 16)
+ bits[ch][sb] = 16;
+ }
+ }
+ }
+
+ ch = 0;
+ sb = 0;
+ while (bitcount < frame->bitpool) {
+ if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) {
+ bits[ch][sb]++;
+ bitcount++;
+ } else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) {
+ bits[ch][sb] = 2;
+ bitcount += 2;
+ }
+ if (ch == 1) {
+ ch = 0;
+ sb++;
+ if (sb >= subbands)
+ break;
+ } else
+ ch = 1;
+ }
+
+ ch = 0;
+ sb = 0;
+ while (bitcount < frame->bitpool) {
+ if (bits[ch][sb] < 16) {
+ bits[ch][sb]++;
+ bitcount++;
+ }
+ if (ch == 1) {
+ ch = 0;
+ sb++;
+ if (sb >= subbands)
+ break;
+ } else
+ ch = 1;
+ }
+
+ }
+
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-14 21:22:24 +0000