[FFmpeg-devel] [PATCH 4/8] sbc: implement SBC encoder (low-complexity subband codec)

[Aurelien Jacobs]

On Mon, Dec 18, 2017 at 12:45:12PM +0100, Michael Niedermayer wrote:
> On Sun, Dec 17, 2017 at 10:47:16PM +0100, Aurelien Jacobs wrote:
> > This was originally based on libsbc, and was fully integrated into ffmpeg.
> > ---
> [...]
> > +static inline void sbc_analyze_4b_4s_simd(SBCDSPContext *s,
> > +                                          int16_t *x, int32_t *out, int out_stride)
> > +{
> > +    /* Analyze blocks */
> > +    s->sbc_analyze_4(x + 12, out, ff_sbcdsp_analysis_consts_fixed4_simd_odd);
> > +    out += out_stride;
> > +    s->sbc_analyze_4(x + 8, out, ff_sbcdsp_analysis_consts_fixed4_simd_even);
> > +    out += out_stride;
> > +    s->sbc_analyze_4(x + 4, out, ff_sbcdsp_analysis_consts_fixed4_simd_odd);
> > +    out += out_stride;
> > +    s->sbc_analyze_4(x + 0, out, ff_sbcdsp_analysis_consts_fixed4_simd_even);
> > +
> > +    emms_c();
> > +}
> > +
> > +static inline void sbc_analyze_4b_8s_simd(SBCDSPContext *s,
> > +                                          int16_t *x, int32_t *out, int out_stride)
> > +{
> > +    /* Analyze blocks */
> > +    s->sbc_analyze_8(x + 24, out, ff_sbcdsp_analysis_consts_fixed8_simd_odd);
> > +    out += out_stride;
> > +    s->sbc_analyze_8(x + 16, out, ff_sbcdsp_analysis_consts_fixed8_simd_even);
> > +    out += out_stride;
> > +    s->sbc_analyze_8(x + 8, out, ff_sbcdsp_analysis_consts_fixed8_simd_odd);
> > +    out += out_stride;
> > +    s->sbc_analyze_8(x + 0, out, ff_sbcdsp_analysis_consts_fixed8_simd_even);
> > +
> > +    emms_c();
> > +}
> > +
> > +static inline void sbc_analyze_1b_8s_simd_even(SBCDSPContext *s,
> > +                                               int16_t *x, int32_t *out,
> > +                                               int out_stride);
> > +
> > +static inline void sbc_analyze_1b_8s_simd_odd(SBCDSPContext *s,
> > +                                              int16_t *x, int32_t *out,
> > +                                              int out_stride)
> > +{
> > +    s->sbc_analyze_8(x, out, ff_sbcdsp_analysis_consts_fixed8_simd_odd);
> > +    s->sbc_analyze_8s = sbc_analyze_1b_8s_simd_even;
> > +
> > +    emms_c();
> > +}
> > +
> > +static inline void sbc_analyze_1b_8s_simd_even(SBCDSPContext *s,
> > +                                               int16_t *x, int32_t *out,
> > +                                               int out_stride)
> > +{
> > +    s->sbc_analyze_8(x, out, ff_sbcdsp_analysis_consts_fixed8_simd_even);
> > +    s->sbc_analyze_8s = sbc_analyze_1b_8s_simd_odd;
> > +
> > +    emms_c();
> > +}
> 
> at least some of the functions are always called in a loop, the emms_c() could
> be called after the loop

Ok, I moved all those emms_c() out of the loop.

> [...]
> > diff --git a/libavcodec/sbcdsp_data.c b/libavcodec/sbcdsp_data.c
> > new file mode 100644
> > index 0000000000..1e19b9d9d1
> > --- /dev/null
> > +++ b/libavcodec/sbcdsp_data.c
> > @@ -0,0 +1,329 @@
> > +/*
> > + * Bluetooth low-complexity, subband codec (SBC)
> > + *
> > + * Copyright (C) 2017  Aurelien Jacobs <aurel at gnuage.org>
> > + * Copyright (C) 2008-2010  Nokia Corporation
> > + * Copyright (C) 2004-2010  Marcel Holtmann <marcel at holtmann.org>
> > + * Copyright (C) 2004-2005  Henryk Ploetz <henryk at ploetzli.ch>
> > + * Copyright (C) 2005-2006  Brad Midgley <bmidgley at 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
> > + * miscellaneous SBC tables
> > + */
> > +
> > +#include "sbcdsp_data.h"
> > +
> > +#define F_PROTO(x) (int32_t) ((x * 2) * ((int32_t) 1 << 15) + 0.5)
> > +#define F_COS(x)   (int32_t) ((x    ) * ((int32_t) 1 << 15) + 0.5)
> 
> this needs more () to protect the argument x and the whole expression
> for example F_PROTO(1+1) would produce unexpected results

Indeed. Fixed in upcomming updated patch set.