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libavfilter/vf_scale.c

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00001 /*
00002  * Copyright (c) 2007 Bobby Bingham
00003  *
00004  * This file is part of Libav.
00005  *
00006  * Libav 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  * Libav 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 Libav; 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 #include "libavutil/avstring.h"
00028 #include "libavutil/eval.h"
00029 #include "libavutil/mathematics.h"
00030 #include "libavutil/pixdesc.h"
00031 #include "libswscale/swscale.h"
00032 
00033 static const char *var_names[] = {
00034     "PI",
00035     "PHI",
00036     "E",
00037     "in_w",   "iw",
00038     "in_h",   "ih",
00039     "out_w",  "ow",
00040     "out_h",  "oh",
00041     "a", "dar",
00042     "sar",
00043     "hsub",
00044     "vsub",
00045     NULL
00046 };
00047 
00048 enum var_name {
00049     VAR_PI,
00050     VAR_PHI,
00051     VAR_E,
00052     VAR_IN_W,   VAR_IW,
00053     VAR_IN_H,   VAR_IH,
00054     VAR_OUT_W,  VAR_OW,
00055     VAR_OUT_H,  VAR_OH,
00056     VAR_A, VAR_DAR,
00057     VAR_SAR,
00058     VAR_HSUB,
00059     VAR_VSUB,
00060     VARS_NB
00061 };
00062 
00063 typedef struct {
00064     struct SwsContext *sws;     
00065 
00071     int w, h;
00072     unsigned int flags;         
00073 
00074     int hsub, vsub;             
00075     int slice_y;                
00076     int input_is_pal;           
00077 
00078     char w_expr[256];           
00079     char h_expr[256];           
00080 } ScaleContext;
00081 
00082 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00083 {
00084     ScaleContext *scale = ctx->priv;
00085     const char *p;
00086 
00087     av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr));
00088     av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr));
00089 
00090     scale->flags = SWS_BILINEAR;
00091     if (args) {
00092         sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);
00093         p = strstr(args,"flags=");
00094         if (p) scale->flags = strtoul(p+6, NULL, 0);
00095     }
00096 
00097     return 0;
00098 }
00099 
00100 static av_cold void uninit(AVFilterContext *ctx)
00101 {
00102     ScaleContext *scale = ctx->priv;
00103     sws_freeContext(scale->sws);
00104     scale->sws = NULL;
00105 }
00106 
00107 static int query_formats(AVFilterContext *ctx)
00108 {
00109     AVFilterFormats *formats;
00110     enum PixelFormat pix_fmt;
00111     int ret;
00112 
00113     if (ctx->inputs[0]) {
00114         formats = NULL;
00115         for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)
00116             if (   sws_isSupportedInput(pix_fmt)
00117                 && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {
00118                 avfilter_formats_unref(&formats);
00119                 return ret;
00120             }
00121         avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats);
00122     }
00123     if (ctx->outputs[0]) {
00124         formats = NULL;
00125         for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)
00126             if (    sws_isSupportedOutput(pix_fmt)
00127                 && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {
00128                 avfilter_formats_unref(&formats);
00129                 return ret;
00130             }
00131         avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats);
00132     }
00133 
00134     return 0;
00135 }
00136 
00137 static int config_props(AVFilterLink *outlink)
00138 {
00139     AVFilterContext *ctx = outlink->src;
00140     AVFilterLink *inlink = outlink->src->inputs[0];
00141     ScaleContext *scale = ctx->priv;
00142     int64_t w, h;
00143     double var_values[VARS_NB], res;
00144     char *expr;
00145     int ret;
00146 
00147     var_values[VAR_PI]    = M_PI;
00148     var_values[VAR_PHI]   = M_PHI;
00149     var_values[VAR_E]     = M_E;
00150     var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;
00151     var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;
00152     var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
00153     var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
00154     var_values[VAR_DAR]   = var_values[VAR_A]  = (float) inlink->w / inlink->h;
00155     var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
00156         (float) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
00157     var_values[VAR_HSUB]  = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
00158     var_values[VAR_VSUB]  = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
00159 
00160     /* evaluate width and height */
00161     av_expr_parse_and_eval(&res, (expr = scale->w_expr),
00162                            var_names, var_values,
00163                            NULL, NULL, NULL, NULL, NULL, 0, ctx);
00164     scale->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
00165     if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),
00166                                       var_names, var_values,
00167                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
00168         goto fail;
00169     scale->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
00170     /* evaluate again the width, as it may depend on the output height */
00171     if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),
00172                                       var_names, var_values,
00173                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
00174         goto fail;
00175     scale->w = res;
00176 
00177     w = scale->w;
00178     h = scale->h;
00179 
00180     /* sanity check params */
00181     if (w <  -1 || h <  -1) {
00182         av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
00183         return AVERROR(EINVAL);
00184     }
00185     if (w == -1 && h == -1)
00186         scale->w = scale->h = 0;
00187 
00188     if (!(w = scale->w))
00189         w = inlink->w;
00190     if (!(h = scale->h))
00191         h = inlink->h;
00192     if (w == -1)
00193         w = av_rescale(h, inlink->w, inlink->h);
00194     if (h == -1)
00195         h = av_rescale(w, inlink->h, inlink->w);
00196 
00197     if (w > INT_MAX || h > INT_MAX ||
00198         (h * inlink->w) > INT_MAX  ||
00199         (w * inlink->h) > INT_MAX)
00200         av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
00201 
00202     outlink->w = w;
00203     outlink->h = h;
00204 
00205     /* TODO: make algorithm configurable */
00206     av_log(ctx, AV_LOG_INFO, "w:%d h:%d fmt:%s -> w:%d h:%d fmt:%s flags:0x%0x\n",
00207            inlink ->w, inlink ->h, av_pix_fmt_descriptors[ inlink->format].name,
00208            outlink->w, outlink->h, av_pix_fmt_descriptors[outlink->format].name,
00209            scale->flags);
00210 
00211     scale->input_is_pal = av_pix_fmt_descriptors[inlink->format].flags & PIX_FMT_PAL;
00212 
00213     if (scale->sws)
00214         sws_freeContext(scale->sws);
00215     scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,
00216                                 outlink->w, outlink->h, outlink->format,
00217                                 scale->flags, NULL, NULL, NULL);
00218     if (!scale->sws)
00219         return AVERROR(EINVAL);
00220 
00221 
00222     if (inlink->sample_aspect_ratio.num)
00223         outlink->sample_aspect_ratio = av_mul_q((AVRational){outlink->h*inlink->w,
00224                                                              outlink->w*inlink->h},
00225                                                 inlink->sample_aspect_ratio);
00226     else
00227         outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
00228 
00229     return 0;
00230 
00231 fail:
00232     av_log(NULL, AV_LOG_ERROR,
00233            "Error when evaluating the expression '%s'\n", expr);
00234     return ret;
00235 }
00236 
00237 static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
00238 {
00239     ScaleContext *scale = link->dst->priv;
00240     AVFilterLink *outlink = link->dst->outputs[0];
00241     AVFilterBufferRef *outpicref;
00242 
00243     scale->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;
00244     scale->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;
00245 
00246     outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
00247     avfilter_copy_buffer_ref_props(outpicref, picref);
00248     outpicref->video->w = outlink->w;
00249     outpicref->video->h = outlink->h;
00250 
00251     outlink->out_buf = outpicref;
00252 
00253     av_reduce(&outpicref->video->pixel_aspect.num, &outpicref->video->pixel_aspect.den,
00254               (int64_t)picref->video->pixel_aspect.num * outlink->h * link->w,
00255               (int64_t)picref->video->pixel_aspect.den * outlink->w * link->h,
00256               INT_MAX);
00257 
00258     scale->slice_y = 0;
00259     avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0));
00260 }
00261 
00262 static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
00263 {
00264     ScaleContext *scale = link->dst->priv;
00265     int out_h;
00266     AVFilterBufferRef *cur_pic = link->cur_buf;
00267     const uint8_t *data[4];
00268 
00269     if (scale->slice_y == 0 && slice_dir == -1)
00270         scale->slice_y = link->dst->outputs[0]->h;
00271 
00272     data[0] = cur_pic->data[0] +  y               * cur_pic->linesize[0];
00273     data[1] = scale->input_is_pal ?
00274               cur_pic->data[1] :
00275               cur_pic->data[1] + (y>>scale->vsub) * cur_pic->linesize[1];
00276     data[2] = cur_pic->data[2] + (y>>scale->vsub) * cur_pic->linesize[2];
00277     data[3] = cur_pic->data[3] +  y               * cur_pic->linesize[3];
00278 
00279     out_h = sws_scale(scale->sws, data, cur_pic->linesize, y, h,
00280                       link->dst->outputs[0]->out_buf->data,
00281                       link->dst->outputs[0]->out_buf->linesize);
00282 
00283     if (slice_dir == -1)
00284         scale->slice_y -= out_h;
00285     avfilter_draw_slice(link->dst->outputs[0], scale->slice_y, out_h, slice_dir);
00286     if (slice_dir == 1)
00287         scale->slice_y += out_h;
00288 }
00289 
00290 AVFilter avfilter_vf_scale = {
00291     .name      = "scale",
00292     .description = NULL_IF_CONFIG_SMALL("Scale the input video to width:height size and/or convert the image format."),
00293 
00294     .init      = init,
00295     .uninit    = uninit,
00296 
00297     .query_formats = query_formats,
00298 
00299     .priv_size = sizeof(ScaleContext),
00300 
00301     .inputs    = (AVFilterPad[]) {{ .name             = "default",
00302                                     .type             = AVMEDIA_TYPE_VIDEO,
00303                                     .start_frame      = start_frame,
00304                                     .draw_slice       = draw_slice,
00305                                     .min_perms        = AV_PERM_READ, },
00306                                   { .name = NULL}},
00307     .outputs   = (AVFilterPad[]) {{ .name             = "default",
00308                                     .type             = AVMEDIA_TYPE_VIDEO,
00309                                     .config_props     = config_props, },
00310                                   { .name = NULL}},
00311 };
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