sbc: implement SBC decoder (low-complexity subband codec)

This was originally based on libsbc, and was fully integrated into ffmpeg.

1 files changed, 118 insertions, 0 deletions

diff --git a/libavcodec/sbc.h b/libavcodec/sbc.h
new file mode 100644
index 0000000000..405fadc3a6
--- /dev/null
+++ b/libavcodec/sbc.h
@@ -0,0 +1,118 @@
+/*
+ * Bluetooth low-complexity, subband codec (SBC)
+ *
+ * Copyright (C) 2017  Aurelien Jacobs <aurel@gnuage.org>
+ * Copyright (C) 2012-2014  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) 2005-2006  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 definitions for the encoder and decoder
+ */
+
+#ifndef AVCODEC_SBC_H
+#define AVCODEC_SBC_H
+
+#include "avcodec.h"
+#include "libavutil/crc.h"
+
+#define MSBC_BLOCKS 15
+
+/* sampling frequency */
+#define SBC_FREQ_16000  0x00
+#define SBC_FREQ_32000  0x01
+#define SBC_FREQ_44100  0x02
+#define SBC_FREQ_48000  0x03
+
+/* blocks */
+#define SBC_BLK_4       0x00
+#define SBC_BLK_8       0x01
+#define SBC_BLK_12      0x02
+#define SBC_BLK_16      0x03
+
+/* channel mode */
+#define SBC_MODE_MONO         0x00
+#define SBC_MODE_DUAL_CHANNEL 0x01
+#define SBC_MODE_STEREO       0x02
+#define SBC_MODE_JOINT_STEREO 0x03
+
+/* allocation method */
+#define SBC_AM_LOUDNESS 0x00
+#define SBC_AM_SNR      0x01
+
+/* subbands */
+#define SBC_SB_4        0x00
+#define SBC_SB_8        0x01
+
+/* synchronisation words */
+#define SBC_SYNCWORD   0x9C
+#define MSBC_SYNCWORD  0xAD
+
+/* extra bits of precision for the synthesis filter input data */
+#define SBCDEC_FIXED_EXTRA_BITS 2
+
+/*
+ * Enforce 16 byte alignment for the data, which is supposed to be used
+ * with SIMD optimized code.
+ */
+#define SBC_ALIGN 16
+
+/* This structure contains an unpacked SBC frame.
+   Yes, there is probably quite some unused space herein */
+struct sbc_frame {
+    uint8_t frequency;
+    uint8_t blocks;
+    enum {
+        MONO         = SBC_MODE_MONO,
+        DUAL_CHANNEL = SBC_MODE_DUAL_CHANNEL,
+        STEREO       = SBC_MODE_STEREO,
+        JOINT_STEREO = SBC_MODE_JOINT_STEREO
+    } mode;
+    uint8_t channels;
+    enum {
+        LOUDNESS = SBC_AM_LOUDNESS,
+        SNR      = SBC_AM_SNR
+    } allocation;
+    uint8_t subbands;
+    uint8_t bitpool;
+    uint16_t codesize;
+
+    /* bit number x set means joint stereo has been used in subband x */
+    uint8_t joint;
+
+    /* only the lower 4 bits of every element are to be used */
+    DECLARE_ALIGNED(SBC_ALIGN, uint32_t, scale_factor)[2][8];
+
+    /* raw integer subband samples in the frame */
+    DECLARE_ALIGNED(SBC_ALIGN, int32_t, sb_sample_f)[16][2][8];
+
+    /* modified subband samples */
+    DECLARE_ALIGNED(SBC_ALIGN, int32_t, sb_sample)[16][2][8];
+
+    const AVCRC *crc_ctx;
+};
+
+uint8_t sbc_crc8(const AVCRC *crc_ctx, const uint8_t *data, size_t len);
+void ff_sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8]);
+
+#endif /* AVCODEC_SBC_H */