/* * 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 * null video source */ #include "avfilter.h" typedef struct {    int w, h;} NullContext; static int init(AVFilterContext *ctx, const char *args, void *opaque){    NullContext *priv = ctx->priv;     priv->w = 352;    priv->h = 288;     if (args)        sscanf(args, "%d:%d", &priv->w, &priv->h);     if (priv->w <= 0 || priv->h <= 0) {        av_log(ctx, AV_LOG_ERROR, "Non-positive size values are not acceptable.\n");        return -1;    }     return 0;} static int config_props(AVFilterLink *outlink){    NullContext *priv = outlink->src->priv;     outlink->w = priv->w;    outlink->h = priv->h;     av_log(outlink->src, AV_LOG_INFO, "w:%d h:%d\n", priv->w, priv->h);     return 0;} static int request_frame(AVFilterLink *link){    return -1;} AVFilter avfilter_vsrc_nullsrc = {    .name        = "nullsrc",    .description = "Null video source, never return images.",     .init       = init,    .priv_size = sizeof(NullContext),     .inputs    = (AVFilterPad[]) {{ .name = NULL}},     .outputs   = (AVFilterPad[]) {        {            .name            = "default",            .type            = AVMEDIA_TYPE_VIDEO,            .config_props    = config_props,            .request_frame   = request_frame,        },        { .name = NULL}    },};