PeerStreamer

/*

 * Copyright (c) 2010 Bobby Bingham

 * 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

 * aspect ratio modification video filters

 */

#include "avfilter.h"

typedef struct {

    AVRational aspect;

} AspectContext;

static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)

{

    AspectContext *aspect = ctx->priv;

    double  ratio;

    int64_t gcd;

    char c = 0;

    if (args) {

        if (sscanf(args, "%d:%d%c", &aspect->aspect.num, &aspect->aspect.den, &c) != 2)

            if (sscanf(args, "%lf%c", &ratio, &c) == 1)

                aspect->aspect = av_d2q(ratio, 100);

        if (c || aspect->aspect.num <= 0 || aspect->aspect.den <= 0) {

            av_log(ctx, AV_LOG_ERROR,

                   "Invalid string '%s' for aspect ratio.\n", args);

            return AVERROR(EINVAL);

        }

        gcd = av_gcd(FFABS(aspect->aspect.num), FFABS(aspect->aspect.den));

        if (gcd) {

            aspect->aspect.num /= gcd;

            aspect->aspect.den /= gcd;

        }

    }

    if (aspect->aspect.den == 0)

        aspect->aspect = (AVRational) {0, 1};

    av_log(ctx, AV_LOG_INFO, "a:%d/%d\n", aspect->aspect.num, aspect->aspect.den);

    return 0;

}

static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)

{

    AspectContext *aspect = link->dst->priv;

    picref->video->pixel_aspect = aspect->aspect;

    avfilter_start_frame(link->dst->outputs[0], picref);

}

#if CONFIG_SETDAR_FILTER

/* for setdar filter, convert from frame aspect ratio to pixel aspect ratio */

static int setdar_config_props(AVFilterLink *inlink)

{

    AspectContext *aspect = inlink->dst->priv;

    AVRational dar = aspect->aspect;

    av_reduce(&aspect->aspect.num, &aspect->aspect.den,

               aspect->aspect.num * inlink->h,

               aspect->aspect.den * inlink->w, 100);

    av_log(inlink->dst, AV_LOG_INFO, "w:%d h:%d -> dar:%d/%d par:%d/%d\n",

           inlink->w, inlink->h, dar.num, dar.den, aspect->aspect.num, aspect->aspect.den);

    inlink->sample_aspect_ratio = aspect->aspect;

    return 0;

}

AVFilter avfilter_vf_setdar = {

    .name      = "setdar",

    .description = NULL_IF_CONFIG_SMALL("Set the frame display aspect ratio."),

    .init      = init,

    .priv_size = sizeof(AspectContext),

    .inputs    = (AVFilterPad[]) {{ .name             = "default",

                                    .type             = AVMEDIA_TYPE_VIDEO,

                                    .config_props     = setdar_config_props,

                                    .get_video_buffer = avfilter_null_get_video_buffer,

                                    .start_frame      = start_frame,

                                    .end_frame        = avfilter_null_end_frame },

                                  { .name = NULL}},

    .outputs   = (AVFilterPad[]) {{ .name             = "default",

                                    .type             = AVMEDIA_TYPE_VIDEO, },

                                  { .name = NULL}},

};

#endif /* CONFIG_SETDAR_FILTER */

#if CONFIG_SETSAR_FILTER

/* for setdar filter, convert from frame aspect ratio to pixel aspect ratio */

static int setsar_config_props(AVFilterLink *inlink)

{

    AspectContext *aspect = inlink->dst->priv;

    inlink->sample_aspect_ratio = aspect->aspect;

    return 0;

}

AVFilter avfilter_vf_setsar = {

    .name      = "setsar",

    .description = NULL_IF_CONFIG_SMALL("Set the pixel sample aspect ratio."),

    .init      = init,

    .priv_size = sizeof(AspectContext),

    .inputs    = (AVFilterPad[]) {{ .name             = "default",

                                    .type             = AVMEDIA_TYPE_VIDEO,

                                    .config_props     = setsar_config_props,

                                    .get_video_buffer = avfilter_null_get_video_buffer,

                                    .start_frame      = start_frame,

                                    .end_frame        = avfilter_null_end_frame },

                                  { .name = NULL}},

    .outputs   = (AVFilterPad[]) {{ .name             = "default",

                                    .type             = AVMEDIA_TYPE_VIDEO, },

                                  { .name = NULL}},

};

#endif /* CONFIG_SETSAR_FILTER */