libavfilter/vf_aspect.c

   1 /*
   2  * Copyright (c) 2010 Bobby Bingham
   3
   4  * This file is part of Libav.
   5  *
   6  * Libav 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  * Libav 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 Libav; 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 "libavutil/common.h"
  27 #include "libavutil/mathematics.h"
  28 #include "avfilter.h"
  29 #include "internal.h"
  30 #include "video.h"
  31
  32 typedef struct {
  33     AVRational aspect;
  34 } AspectContext;
  35
  36 static av_cold int init(AVFilterContext *ctx, const char *args)
  37 {
  38     AspectContext *aspect = ctx->priv;
  39     double  ratio;
  40     int64_t gcd;
  41     char c = 0;
  42
  43     if (args) {
  44         if (sscanf(args, "%d:%d%c", &aspect->aspect.num, &aspect->aspect.den, &c) != 2)
  45             if (sscanf(args, "%lf%c", &ratio, &c) == 1)
  46                 aspect->aspect = av_d2q(ratio, 100);
  47
  48         if (c || aspect->aspect.num <= 0 || aspect->aspect.den <= 0) {
  49             av_log(ctx, AV_LOG_ERROR,
  50                    "Invalid string '%s' for aspect ratio.\n", args);
  51             return AVERROR(EINVAL);
  52         }
  53
  54         gcd = av_gcd(FFABS(aspect->aspect.num), FFABS(aspect->aspect.den));
  55         if (gcd) {
  56             aspect->aspect.num /= gcd;
  57             aspect->aspect.den /= gcd;
  58         }
  59     }
  60
  61     if (aspect->aspect.den == 0)
  62         aspect->aspect = (AVRational) {0, 1};
  63
  64     av_log(ctx, AV_LOG_VERBOSE, "a:%d/%d\n", aspect->aspect.num, aspect->aspect.den);
  65     return 0;
  66 }
  67
  68 static int filter_frame(AVFilterLink *link, AVFilterBufferRef *frame)
  69 {
  70     AspectContext *aspect = link->dst->priv;
  71
  72     frame->video->pixel_aspect = aspect->aspect;
  73     return ff_filter_frame(link->dst->outputs[0], frame);
  74 }
  75
  76 #if CONFIG_SETDAR_FILTER
  77 /* for setdar filter, convert from frame aspect ratio to pixel aspect ratio */
  78 static int setdar_config_props(AVFilterLink *inlink)
  79 {
  80     AspectContext *aspect = inlink->dst->priv;
  81     AVRational dar = aspect->aspect;
  82
  83     av_reduce(&aspect->aspect.num, &aspect->aspect.den,
  84                aspect->aspect.num * inlink->h,
  85                aspect->aspect.den * inlink->w, 100);
  86
  87     av_log(inlink->dst, AV_LOG_VERBOSE, "w:%d h:%d -> dar:%d/%d sar:%d/%d\n",
  88            inlink->w, inlink->h, dar.num, dar.den, aspect->aspect.num, aspect->aspect.den);
  89
  90     inlink->sample_aspect_ratio = aspect->aspect;
  91
  92     return 0;
  93 }
  94
  95 static const AVFilterPad avfilter_vf_setdar_inputs[] = {
  96     {
  97         .name             = "default",
  98         .type             = AVMEDIA_TYPE_VIDEO,
  99         .config_props     = setdar_config_props,
 100         .get_video_buffer = ff_null_get_video_buffer,
 101         .filter_frame     = filter_frame,
 102     },
 103     { NULL }
 104 };
 105
 106 static const AVFilterPad avfilter_vf_setdar_outputs[] = {
 107     {
 108         .name = "default",
 109         .type = AVMEDIA_TYPE_VIDEO,
 110     },
 111     { NULL }
 112 };
 113
 114 AVFilter avfilter_vf_setdar = {
 115     .name      = "setdar",
 116     .description = NULL_IF_CONFIG_SMALL("Set the frame display aspect ratio."),
 117
 118     .init      = init,
 119
 120     .priv_size = sizeof(AspectContext),
 121
 122     .inputs    = avfilter_vf_setdar_inputs,
 123
 124     .outputs   = avfilter_vf_setdar_outputs,
 125 };
 126 #endif /* CONFIG_SETDAR_FILTER */
 127
 128 #if CONFIG_SETSAR_FILTER
 129 /* for setdar filter, convert from frame aspect ratio to pixel aspect ratio */
 130 static int setsar_config_props(AVFilterLink *inlink)
 131 {
 132     AspectContext *aspect = inlink->dst->priv;
 133
 134     inlink->sample_aspect_ratio = aspect->aspect;
 135
 136     return 0;
 137 }
 138
 139 static const AVFilterPad avfilter_vf_setsar_inputs[] = {
 140     {
 141         .name             = "default",
 142         .type             = AVMEDIA_TYPE_VIDEO,
 143         .config_props     = setsar_config_props,
 144         .get_video_buffer = ff_null_get_video_buffer,
 145         .filter_frame     = filter_frame,
 146     },
 147     { NULL }
 148 };
 149
 150 static const AVFilterPad avfilter_vf_setsar_outputs[] = {
 151     {
 152         .name = "default",
 153         .type = AVMEDIA_TYPE_VIDEO,
 154     },
 155     { NULL }
 156 };
 157
 158 AVFilter avfilter_vf_setsar = {
 159     .name      = "setsar",
 160     .description = NULL_IF_CONFIG_SMALL("Set the pixel sample aspect ratio."),
 161
 162     .init      = init,
 163
 164     .priv_size = sizeof(AspectContext),
 165
 166     .inputs    = avfilter_vf_setsar_inputs,
 167
 168     .outputs   = avfilter_vf_setsar_outputs,
 169 };
 170 #endif /* CONFIG_SETSAR_FILTER */