ffmpeg/libavfilter/vf_aspect.c

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/*
* Aspect ratio modification video filter
* Copyright (c) 2010 Bobby Bingham
* 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
* aspect ratio modification video filter
*/
#include "avfilter.h"
typedef struct {
AVRational aspect;
} AspectContext;
static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
{
AspectContext *aspect = ctx->priv;
double ratio;
int64_t gcd;
if(args) {
if(sscanf(args, "%d:%d", &aspect->aspect.num, &aspect->aspect.den) < 2) {
if(sscanf(args, "%lf", &ratio) < 1)
return -1;
aspect->aspect = av_d2q(ratio, 100);
} else {
gcd = av_gcd(FFABS(aspect->aspect.num), FFABS(aspect->aspect.den));
if(gcd) {
aspect->aspect.num /= gcd;
aspect->aspect.den /= gcd;
}
}
}
if(aspect->aspect.den == 0)
aspect->aspect = (AVRational) {0, 1};
return 0;
}
static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
{
AspectContext *aspect = link->dst->priv;
picref->pixel_aspect = aspect->aspect;
avfilter_start_frame(link->dst->outputs[0], picref);
}
#if CONFIG_ASPECT_FILTER
/* for aspect filter, convert from frame aspect ratio to pixel aspect ratio */
static int frameaspect_config_props(AVFilterLink *inlink)
{
AspectContext *aspect = inlink->dst->priv;
av_reduce(&aspect->aspect.num, &aspect->aspect.den,
aspect->aspect.num * inlink->h,
aspect->aspect.den * inlink->w, 100);
return 0;
}
AVFilter avfilter_vf_aspect = {
.name = "aspect",
.description = NULL_IF_CONFIG_SMALL("Set the frame aspect ratio."),
.init = init,
.priv_size = sizeof(AspectContext),
.inputs = (AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = frameaspect_config_props,
.get_video_buffer = avfilter_null_get_video_buffer,
.start_frame = start_frame,
.end_frame = avfilter_null_end_frame },
{ .name = NULL}},
.outputs = (AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO, },
{ .name = NULL}},
};
#endif /* CONFIG_ASPECT_FILTER */
#if CONFIG_PIXELASPECT_FILTER
AVFilter avfilter_vf_pixelaspect = {
.name = "pixelaspect",
.description = NULL_IF_CONFIG_SMALL("Set the pixel aspect ratio."),
.init = init,
.priv_size = sizeof(AspectContext),
.inputs = (AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.get_video_buffer = avfilter_null_get_video_buffer,
.start_frame = start_frame,
.end_frame = avfilter_null_end_frame },
{ .name = NULL}},
.outputs = (AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO, },
{ .name = NULL}},
};
#endif /* CONFIG_PIXELASPECT_FILTER */