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/avstring.h"

#include "libavutil/eval.h"

#include "libavutil/pixdesc.h"

#include "libavutil/avassert.h"

#include "libswscale/swscale.h"

static const char *var_names[] = {

    "PI",

    "PHI",

    "E",

    "in_w",   "iw",

    "in_h",   "ih",

    "out_w",  "ow",

    "out_h",  "oh",

    "a",

    "hsub",

    "vsub",

    NULL

};

enum var_name {

    VAR_PI,

    VAR_PHI,

    VAR_E,

    VAR_IN_W,   VAR_IW,

    VAR_IN_H,   VAR_IH,

    VAR_OUT_W,  VAR_OW,

    VAR_OUT_H,  VAR_OH,

    VAR_A,

    VAR_HSUB,

    VAR_VSUB,

    VARS_NB

};

typedef struct {

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

    struct SwsContext *isws[2]; ///< software scaler context for interlaced material

    /**

     * 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

    int interlaced;

    char w_expr[256];             ///< width  expression string

    char h_expr[256];             ///< height expression string

} ScaleContext;

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

{

    ScaleContext *scale = ctx->priv;

    const char *p;

    av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr));

    av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr));

    scale->flags = SWS_BILINEAR;

    if (args) {

        sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);

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

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

        if(strstr(args,"interl=1")){

            scale->interlaced=1;

        }else if(strstr(args,"interl=-1"))

            scale->interlaced=-1;

    }

    return 0;

}

static av_cold void uninit(AVFilterContext *ctx)

{

    ScaleContext *scale = ctx->priv;

    sws_freeContext(scale->sws);

    sws_freeContext(scale->isws[0]);

    sws_freeContext(scale->isws[1]);

    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;

    double var_values[VARS_NB], res;

    char *expr;

    int ret;

    var_values[VAR_PI]    = M_PI;

    var_values[VAR_PHI]   = M_PHI;

    var_values[VAR_E]     = M_E;

    var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;

    var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;

    var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;

    var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;

    var_values[VAR_A]     = (float) inlink->w / inlink->h;

    var_values[VAR_HSUB]  = 2<<av_pix_fmt_descriptors[inlink->format].log2_chroma_w;

    var_values[VAR_VSUB]  = 2<<av_pix_fmt_descriptors[inlink->format].log2_chroma_h;

    /* evaluate width and height */

    av_expr_parse_and_eval(&res, (expr = scale->w_expr),

                           var_names, var_values,

                           NULL, NULL, NULL, NULL, NULL, 0, ctx);

    scale->w = var_values[VAR_OW] = res;

    if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),

                                      var_names, var_values,

                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)

        goto fail;

    scale->h = var_values[VAR_OH] = res;

    /* evaluate again the width, as it may depend on the output height */

    if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),

                                      var_names, var_values,

                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)

        goto fail;

    scale->w = res;

    w = scale->w;

    h = scale->h;

    /* sanity check params */

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

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

        return AVERROR(EINVAL);

    }

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

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

    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;

    if(scale->sws)

        sws_freeContext(scale->sws);

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

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

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

    scale->isws[0] = sws_getContext(inlink ->w, inlink ->h/2, inlink ->format,

                                    outlink->w, outlink->h/2, outlink->format,

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

    scale->isws[1] = sws_getContext(inlink ->w, inlink ->h/2, inlink ->format,

                                    outlink->w, outlink->h/2, outlink->format,

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

    if (!scale->sws)

        return AVERROR(EINVAL);

    return 0;

fail:

    av_log(NULL, AV_LOG_ERROR,

           "Error when evaluating the expression '%s'\n", expr);

    return ret;

}

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);

    outpicref->video->w = outlink->w;

    outpicref->video->h = outlink->h;

    outlink->out_buf = outpicref;

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

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

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

              INT_MAX);

    scale->slice_y = 0;

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

}

static int scale_slice(AVFilterLink *link, struct SwsContext *sws, int y, int h, int mul, int field)

{

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

    AVFilterBufferRef *cur_pic = link->cur_buf;

    AVFilterBufferRef *out_buf = link->dst->outputs[0]->out_buf;

    const uint8_t *in[4], *out[4];

    int in_stride[4],out_stride[4];

    int i;

    for(i=0; i<4; i++){

        int vsub= ((i+1)&2) ? scale->vsub : 0;

         in_stride[i] = cur_pic->linesize[i] * mul;

        out_stride[i] = out_buf->linesize[i] * mul;

         in[i] = cur_pic->data[i] + ((y>>vsub)+field) * cur_pic->linesize[i];

        out[i] = out_buf->data[i] +            field  * out_buf->linesize[i];

    }

    if(scale->input_is_pal){

         in[1] = cur_pic->data[1];

        out[1] = out_buf->data[1];

    }

    return sws_scale(sws, in, in_stride, y/mul, h,

                         out,out_stride);

}

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

{

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

    int out_h;

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

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

    if(scale->interlaced>0 || (scale->interlaced<0 && link->cur_buf->video->interlaced)){

        av_assert0(y%4 == 0);

        out_h = scale_slice(link, scale->isws[0], y, (h+1)/2, 2, 0);

        out_h+= scale_slice(link, scale->isws[1], y,  h   /2, 2, 1);

    }else{

        out_h = scale_slice(link, scale->sws, y, h, 1, 0);

    }

    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 = NULL_IF_CONFIG_SMALL("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}},

};