PeerStreamer

/*

 * copyright (c) 2007 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

 * scale video filter

 */

#include "avfilter.h"

#include "libavutil/pixdesc.h"

#include "libswscale/swscale.h"

typedef struct {

    struct SwsContext *sws;     ///< software scaler context

    /**

     * New dimensions. Special values are:

     *   0 = original width/height

     *  -1 = keep original aspect

     */

    int w, h;

    unsigned int flags;         ///sws flags

    int hsub, vsub;             ///< chroma subsampling

    int slice_y;                ///< top of current output slice

    int input_is_pal;           ///< set to 1 if the input format is paletted

} ScaleContext;

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

{

    ScaleContext *scale = ctx->priv;

    const char *p;

    scale->flags = SWS_BILINEAR;

    if (args){

        sscanf(args, "%d:%d", &scale->w, &scale->h);

        p= strstr(args,"flags=");

        if(p) scale->flags= strtoul(p+6, NULL, 0);

    }

    /* sanity check params */

    if (scale->w <  -1 || scale->h <  -1) {

        av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");

        return -1;

    }

    if (scale->w == -1 && scale->h == -1)

        scale->w = scale->h = 0;

    return 0;

}

static av_cold void uninit(AVFilterContext *ctx)

{

    ScaleContext *scale = ctx->priv;

    sws_freeContext(scale->sws);

    scale->sws = NULL;

}

static int query_formats(AVFilterContext *ctx)

{

    AVFilterFormats *formats;

    enum PixelFormat pix_fmt;

    int ret;

    if (ctx->inputs[0]) {

        formats = NULL;

        for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)

            if (   sws_isSupportedInput(pix_fmt)

                && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {

                avfilter_formats_unref(&formats);

                return ret;

            }

        avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats);

    }

    if (ctx->outputs[0]) {

        formats = NULL;

        for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)

            if (    sws_isSupportedOutput(pix_fmt)

                && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {

                avfilter_formats_unref(&formats);

                return ret;

            }

        avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats);

    }

    return 0;

}

static int config_props(AVFilterLink *outlink)

{

    AVFilterContext *ctx = outlink->src;

    AVFilterLink *inlink = outlink->src->inputs[0];

    ScaleContext *scale = ctx->priv;

    int64_t w, h;

    if (!(w = scale->w))

        w = inlink->w;

    if (!(h = scale->h))

        h = inlink->h;

    if (w == -1)

        w = av_rescale(h, inlink->w, inlink->h);

    if (h == -1)

        h = av_rescale(w, inlink->h, inlink->w);

    if (w > INT_MAX || h > INT_MAX ||

        (h * inlink->w) > INT_MAX  ||

        (w * inlink->h) > INT_MAX)

        av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");

    outlink->w = w;

    outlink->h = h;

    /* TODO: make algorithm configurable */

    av_log(ctx, AV_LOG_INFO, "w:%d h:%d fmt:%s -> w:%d h:%d fmt:%s flags:0x%0x\n",

           inlink ->w, inlink ->h, av_pix_fmt_descriptors[ inlink->format].name,

           outlink->w, outlink->h, av_pix_fmt_descriptors[outlink->format].name,

           scale->flags);

    scale->input_is_pal = av_pix_fmt_descriptors[inlink->format].flags & PIX_FMT_PAL;

    scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,

                                outlink->w, outlink->h, outlink->format,

                                scale->flags, NULL, NULL, NULL);

    return !scale->sws;

}

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

{

    ScaleContext *scale = link->dst->priv;

    AVFilterLink *outlink = link->dst->outputs[0];

    AVFilterBufferRef *outpicref;

    scale->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;

    scale->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;

    outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);

    avfilter_copy_buffer_ref_props(outpicref, picref);

    outlink->outpic = outpicref;

    av_reduce(&outpicref->pixel_aspect.num, &outpicref->pixel_aspect.den,

              (int64_t)picref->pixel_aspect.num * outlink->h * link->w,

              (int64_t)picref->pixel_aspect.den * outlink->w * link->h,

              INT_MAX);

    scale->slice_y = 0;

    avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0));

}

static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)

{

    ScaleContext *scale = link->dst->priv;

    int out_h;

    AVFilterBufferRef *cur_pic = link->cur_pic;

    const uint8_t *data[4];

    if (scale->slice_y == 0 && slice_dir == -1)

        scale->slice_y = link->dst->outputs[0]->h;

    data[0] = cur_pic->data[0] +  y               * cur_pic->linesize[0];

    data[1] = scale->input_is_pal ?

              cur_pic->data[1] :

              cur_pic->data[1] + (y>>scale->vsub) * cur_pic->linesize[1];

    data[2] = cur_pic->data[2] + (y>>scale->vsub) * cur_pic->linesize[2];

    data[3] = cur_pic->data[3] +  y               * cur_pic->linesize[3];

    out_h = sws_scale(scale->sws, data, cur_pic->linesize, y, h,

                      link->dst->outputs[0]->outpic->data,

                      link->dst->outputs[0]->outpic->linesize);

    if (slice_dir == -1)

        scale->slice_y -= out_h;

    avfilter_draw_slice(link->dst->outputs[0], scale->slice_y, out_h, slice_dir);

    if (slice_dir == 1)

        scale->slice_y += out_h;

}

AVFilter avfilter_vf_scale = {

    .name      = "scale",

    .description = "Scale the input video to width:height size and/or convert the image format.",

    .init      = init,

    .uninit    = uninit,

    .query_formats = query_formats,

    .priv_size = sizeof(ScaleContext),

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

                                    .type             = AVMEDIA_TYPE_VIDEO,

                                    .start_frame      = start_frame,

                                    .draw_slice       = draw_slice,

                                    .min_perms        = AV_PERM_READ, },

                                  { .name = NULL}},

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

                                    .type             = AVMEDIA_TYPE_VIDEO,

                                    .config_props     = config_props, },

                                  { .name = NULL}},

};