git.sesse.net Git - ffmpeg/blob - libavfilter/vf_aspect.c

   1 /*
   2  * Copyright (c) 2010 Bobby Bingham
   3
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * aspect ratio modification video filters
  24  */
  25
  26 #include "avfilter.h"
  27
  28 typedef struct {
  29     AVRational aspect;
  30 } AspectContext;
  31
  32 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
  33 {
  34     AspectContext *aspect = ctx->priv;
  35     double  ratio;
  36     int64_t gcd;
  37
  38     if(args) {
  39         if(sscanf(args, "%d:%d", &aspect->aspect.num, &aspect->aspect.den) < 2) {
  40             if(sscanf(args, "%lf", &ratio) < 1)
  41                 return -1;
  42             aspect->aspect = av_d2q(ratio, 100);
  43         } else {
  44             gcd = av_gcd(FFABS(aspect->aspect.num), FFABS(aspect->aspect.den));
  45             if(gcd) {
  46                 aspect->aspect.num /= gcd;
  47                 aspect->aspect.den /= gcd;
  48             }
  49         }
  50     }
  51
  52     if(aspect->aspect.den == 0)
  53         aspect->aspect = (AVRational) {0, 1};
  54
  55     return 0;
  56 }
  57
  58 static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
  59 {
  60     AspectContext *aspect = link->dst->priv;
  61
  62     picref->video->pixel_aspect = aspect->aspect;
  63     avfilter_start_frame(link->dst->outputs[0], picref);
  64 }
  65
  66 #if CONFIG_ASPECT_FILTER
  67 /* for aspect filter, convert from frame aspect ratio to pixel aspect ratio */
  68 static int frameaspect_config_props(AVFilterLink *inlink)
  69 {
  70     AspectContext *aspect = inlink->dst->priv;
  71
  72     av_reduce(&aspect->aspect.num, &aspect->aspect.den,
  73                aspect->aspect.num * inlink->h,
  74                aspect->aspect.den * inlink->w, 100);
  75
  76     return 0;
  77 }
  78
  79 AVFilter avfilter_vf_aspect = {
  80     .name      = "aspect",
  81     .description = NULL_IF_CONFIG_SMALL("Set the frame aspect ratio."),
  82
  83     .init      = init,
  84
  85     .priv_size = sizeof(AspectContext),
  86
  87     .inputs    = (AVFilterPad[]) {{ .name             = "default",
  88                                     .type             = AVMEDIA_TYPE_VIDEO,
  89                                     .config_props     = frameaspect_config_props,
  90                                     .get_video_buffer = avfilter_null_get_video_buffer,
  91                                     .start_frame      = start_frame,
  92                                     .end_frame        = avfilter_null_end_frame },
  93                                   { .name = NULL}},
  94
  95     .outputs   = (AVFilterPad[]) {{ .name             = "default",
  96                                     .type             = AVMEDIA_TYPE_VIDEO, },
  97                                   { .name = NULL}},
  98 };
  99 #endif /* CONFIG_ASPECT_FILTER */
 100
 101 #if CONFIG_PIXELASPECT_FILTER
 102 AVFilter avfilter_vf_pixelaspect = {
 103     .name      = "pixelaspect",
 104     .description = NULL_IF_CONFIG_SMALL("Set the pixel aspect ratio."),
 105
 106     .init      = init,
 107
 108     .priv_size = sizeof(AspectContext),
 109
 110     .inputs    = (AVFilterPad[]) {{ .name             = "default",
 111                                     .type             = AVMEDIA_TYPE_VIDEO,
 112                                     .get_video_buffer = avfilter_null_get_video_buffer,
 113                                     .start_frame      = start_frame,
 114                                     .end_frame        = avfilter_null_end_frame },
 115                                   { .name = NULL}},
 116
 117     .outputs   = (AVFilterPad[]) {{ .name             = "default",
 118                                     .type             = AVMEDIA_TYPE_VIDEO, },
 119                                   { .name = NULL}},
 120 };
 121 #endif /* CONFIG_PIXELASPECT_FILTER */
 122