[FFmpeg-devel] port mplayer eq filter to libavfilter

[Aurelien Jacobs]

On Tue, Nov 23, 2010 at 05:18:08PM +0800, William Yu wrote:
> >> [...]
> >> diff --git a/libavfilter/eq.h b/libavfilter/eq.h
> >> new file mode 100644
> >> index 0000000..7084e5c
> >> --- /dev/null
> >> +++ b/libavfilter/eq.h
> >> @@ -0,0 +1,34 @@
> >> +/*
> >> + * Ported to FFmpeg from MPlayer libmpcodecs/vf_eq.c
> >> + * Port copyright (C) 2010 William Yu <genwillyu at gmail dot 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
> >> + */
> >> +
> >> +#ifndef AVFILTER_EQ_H
> >> +#define AVFILTER_EQ_H
> >> +
> >> +#include "avfilter.h"
> >> +
> >> +#if HAVE_MMX
> >
> > This #if shouldn't be needed.
> I think add this #if can reduce code when some people config it for
> NOT use MMX, another side i think this can help compile it under other
> arch. Is this correct?

No. This #if won't reduce code and won't help compiling under other arch.

> >> [...]
> >> +static av_cold int init(AVFilterContext *ctx, const char * args, void * opaque)
> >> +{
> >> + ? ?EQContext * eq = ctx->priv;
> >> + ? ?av_unused int cpu_flags = av_get_cpu_flags();
> >> +
> >> + ? ?eq->brightness = 0;
> >> + ? ?eq->contrast = 0;
> >> +
> >> + ? ?if (args)
> >> + ? ? ? ?sscanf(args, "%d:%d", &(eq->brightness), &(eq->contrast));
> >> +
> >> + ? ?if (eq->brightness < -100 || eq->brightness > 100 ||
> >> + ? ? ? ?eq->contrast < -100 || eq->contrast > 100) {
> >> + ? ? ? ?av_log(ctx, AV_LOG_ERROR,
> >> + ? ? ? ? ? ? ? ?"Invalid brightness or contrast value %d:%d\n",
> >> + ? ? ? ? ? ? ? ?eq->brightness, eq->contrast);
> >> + ? ? ? ?return AVERROR(EINVAL);
> >> + ? ?}
> >> +
> >> + ? ?av_log(ctx, AV_LOG_INFO,
> >> + ? ? ? ?"brightness and contrast value %d:%d\n",
> >> + ? ? ? ?eq->brightness, eq->contrast);
> >> + ? ?eq->process = process_c;
> >> +#if HAVE_MMX
> >> + ? ?if (HAVE_MMX && cpu_flags & AV_CPU_FLAG_MMX) {
> >> + ? ? ? ?av_log(ctx,AV_LOG_INFO,"use mmx\n");
> >> + ? ? ? ?eq->process = ff_eq_filter_process_mmx;
> >> + ? ?}
> >> +#endif
> >
> > And here again, the #if could be removed.
> I think if we config HAVE_MMX to 0, we need not compile these code.

The if(HAVE_MMX && ...) is enough so that the code is dropped by the
optimizer when HAVE_MMX is 0.

Aurel