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libavfilter/vf_aspect.c

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00001 /*
00002  * Copyright (c) 2010 Bobby Bingham
00003 
00004  * This file is part of FFmpeg.
00005  *
00006  * FFmpeg is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU Lesser General Public
00008  * License as published by the Free Software Foundation; either
00009  * version 2.1 of the License, or (at your option) any later version.
00010  *
00011  * FFmpeg is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014  * Lesser General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU Lesser General Public
00017  * License along with FFmpeg; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00019  */
00020 
00026 #include "avfilter.h"
00027 
00028 typedef struct {
00029     AVRational aspect;
00030 } AspectContext;
00031 
00032 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00033 {
00034     AspectContext *aspect = ctx->priv;
00035     double  ratio;
00036     int64_t gcd;
00037     char c = 0;
00038 
00039     if (args) {
00040         if (sscanf(args, "%d:%d%c", &aspect->aspect.num, &aspect->aspect.den, &c) != 2)
00041             if (sscanf(args, "%lf%c", &ratio, &c) == 1)
00042                 aspect->aspect = av_d2q(ratio, 100);
00043 
00044         if (c || aspect->aspect.num <= 0 || aspect->aspect.den <= 0) {
00045             av_log(ctx, AV_LOG_ERROR,
00046                    "Invalid string '%s' for aspect ratio.\n", args);
00047             return AVERROR(EINVAL);
00048         }
00049 
00050         gcd = av_gcd(FFABS(aspect->aspect.num), FFABS(aspect->aspect.den));
00051         if (gcd) {
00052             aspect->aspect.num /= gcd;
00053             aspect->aspect.den /= gcd;
00054         }
00055     }
00056 
00057     if (aspect->aspect.den == 0)
00058         aspect->aspect = (AVRational) {0, 1};
00059 
00060     av_log(ctx, AV_LOG_INFO, "a:%d/%d\n", aspect->aspect.num, aspect->aspect.den);
00061     return 0;
00062 }
00063 
00064 static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
00065 {
00066     AspectContext *aspect = link->dst->priv;
00067 
00068     picref->video->sample_aspect_ratio = aspect->aspect;
00069     avfilter_start_frame(link->dst->outputs[0], picref);
00070 }
00071 
00072 #if CONFIG_SETDAR_FILTER
00073 /* for setdar filter, convert from frame aspect ratio to pixel aspect ratio */
00074 static int setdar_config_props(AVFilterLink *inlink)
00075 {
00076     AspectContext *aspect = inlink->dst->priv;
00077     AVRational dar = aspect->aspect;
00078 
00079     av_reduce(&aspect->aspect.num, &aspect->aspect.den,
00080                aspect->aspect.num * inlink->h,
00081                aspect->aspect.den * inlink->w, 100);
00082 
00083     av_log(inlink->dst, AV_LOG_INFO, "w:%d h:%d -> dar:%d/%d sar:%d/%d\n",
00084            inlink->w, inlink->h, dar.num, dar.den, aspect->aspect.num, aspect->aspect.den);
00085 
00086     inlink->sample_aspect_ratio = aspect->aspect;
00087 
00088     return 0;
00089 }
00090 
00091 AVFilter avfilter_vf_setdar = {
00092     .name      = "setdar",
00093     .description = NULL_IF_CONFIG_SMALL("Set the frame display aspect ratio."),
00094 
00095     .init      = init,
00096 
00097     .priv_size = sizeof(AspectContext),
00098 
00099     .inputs    = (AVFilterPad[]) {{ .name             = "default",
00100                                     .type             = AVMEDIA_TYPE_VIDEO,
00101                                     .config_props     = setdar_config_props,
00102                                     .get_video_buffer = avfilter_null_get_video_buffer,
00103                                     .start_frame      = start_frame,
00104                                     .end_frame        = avfilter_null_end_frame },
00105                                   { .name = NULL}},
00106 
00107     .outputs   = (AVFilterPad[]) {{ .name             = "default",
00108                                     .type             = AVMEDIA_TYPE_VIDEO, },
00109                                   { .name = NULL}},
00110 };
00111 #endif /* CONFIG_SETDAR_FILTER */
00112 
00113 #if CONFIG_SETSAR_FILTER
00114 /* for setdar filter, convert from frame aspect ratio to pixel aspect ratio */
00115 static int setsar_config_props(AVFilterLink *inlink)
00116 {
00117     AspectContext *aspect = inlink->dst->priv;
00118 
00119     inlink->sample_aspect_ratio = aspect->aspect;
00120 
00121     return 0;
00122 }
00123 
00124 AVFilter avfilter_vf_setsar = {
00125     .name      = "setsar",
00126     .description = NULL_IF_CONFIG_SMALL("Set the pixel sample aspect ratio."),
00127 
00128     .init      = init,
00129 
00130     .priv_size = sizeof(AspectContext),
00131 
00132     .inputs    = (AVFilterPad[]) {{ .name             = "default",
00133                                     .type             = AVMEDIA_TYPE_VIDEO,
00134                                     .config_props     = setsar_config_props,
00135                                     .get_video_buffer = avfilter_null_get_video_buffer,
00136                                     .start_frame      = start_frame,
00137                                     .end_frame        = avfilter_null_end_frame },
00138                                   { .name = NULL}},
00139 
00140     .outputs   = (AVFilterPad[]) {{ .name             = "default",
00141                                     .type             = AVMEDIA_TYPE_VIDEO, },
00142                                   { .name = NULL}},
00143 };
00144 #endif /* CONFIG_SETSAR_FILTER */
00145 

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