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ffmpeg / libavfilter / vf_aspect.c @ bdb47f3a

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/*
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 * Copyright (c) 2010 Bobby Bingham
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * aspect ratio modification video filters
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 */
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#include "avfilter.h"
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typedef struct {
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    AVRational aspect;
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} AspectContext;
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static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
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{
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    AspectContext *aspect = ctx->priv;
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    double  ratio;
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    int64_t gcd;
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    if (args) {
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        if (sscanf(args, "%d:%d", &aspect->aspect.num, &aspect->aspect.den) < 2) {
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            if (sscanf(args, "%lf", &ratio) < 1)
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                return -1;
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            aspect->aspect = av_d2q(ratio, 100);
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        } else {
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            gcd = av_gcd(FFABS(aspect->aspect.num), FFABS(aspect->aspect.den));
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            if (gcd) {
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                aspect->aspect.num /= gcd;
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                aspect->aspect.den /= gcd;
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            }
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        }
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    }
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    if (aspect->aspect.den == 0)
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        aspect->aspect = (AVRational) {0, 1};
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    return 0;
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}
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static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
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{
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    AspectContext *aspect = link->dst->priv;
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    picref->video->pixel_aspect = aspect->aspect;
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    avfilter_start_frame(link->dst->outputs[0], picref);
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}
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#if CONFIG_ASPECT_FILTER
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/* for aspect filter, convert from frame aspect ratio to pixel aspect ratio */
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static int frameaspect_config_props(AVFilterLink *inlink)
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{
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    AspectContext *aspect = inlink->dst->priv;
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    av_reduce(&aspect->aspect.num, &aspect->aspect.den,
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               aspect->aspect.num * inlink->h,
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               aspect->aspect.den * inlink->w, 100);
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    return 0;
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}
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AVFilter avfilter_vf_aspect = {
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    .name      = "aspect",
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    .description = NULL_IF_CONFIG_SMALL("Set the frame aspect ratio."),
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    .init      = init,
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    .priv_size = sizeof(AspectContext),
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    .inputs    = (AVFilterPad[]) {{ .name             = "default",
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                                    .type             = AVMEDIA_TYPE_VIDEO,
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                                    .config_props     = frameaspect_config_props,
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                                    .get_video_buffer = avfilter_null_get_video_buffer,
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                                    .start_frame      = start_frame,
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                                    .end_frame        = avfilter_null_end_frame },
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                                  { .name = NULL}},
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    .outputs   = (AVFilterPad[]) {{ .name             = "default",
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                                    .type             = AVMEDIA_TYPE_VIDEO, },
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                                  { .name = NULL}},
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};
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#endif /* CONFIG_ASPECT_FILTER */
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#if CONFIG_PIXELASPECT_FILTER
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AVFilter avfilter_vf_pixelaspect = {
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    .name      = "pixelaspect",
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    .description = NULL_IF_CONFIG_SMALL("Set the pixel aspect ratio."),
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    .init      = init,
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    .priv_size = sizeof(AspectContext),
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    .inputs    = (AVFilterPad[]) {{ .name             = "default",
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                                    .type             = AVMEDIA_TYPE_VIDEO,
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                                    .get_video_buffer = avfilter_null_get_video_buffer,
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                                    .start_frame      = start_frame,
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                                    .end_frame        = avfilter_null_end_frame },
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                                  { .name = NULL}},
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    .outputs   = (AVFilterPad[]) {{ .name             = "default",
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                                    .type             = AVMEDIA_TYPE_VIDEO, },
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                                  { .name = NULL}},
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};
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#endif /* CONFIG_PIXELASPECT_FILTER */
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