libavfilter/vf_scale.c
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00001 /*
00002  * Copyright (c) 2007 Bobby Bingham
00003  *
00004  * This file is part of FFmpeg.
00005  *
00006  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 "libavutil/avassert.h"
00032 #include "libswscale/swscale.h"
00033 
00034 static const char * const var_names[] = {
00035     "in_w",   "iw",
00036     "in_h",   "ih",
00037     "out_w",  "ow",
00038     "out_h",  "oh",
00039     "a",
00040     "sar",
00041     "dar",
00042     "hsub",
00043     "vsub",
00044     NULL
00045 };
00046 
00047 enum var_name {
00048     VAR_IN_W,   VAR_IW,
00049     VAR_IN_H,   VAR_IH,
00050     VAR_OUT_W,  VAR_OW,
00051     VAR_OUT_H,  VAR_OH,
00052     VAR_A,
00053     VAR_SAR,
00054     VAR_DAR,
00055     VAR_HSUB,
00056     VAR_VSUB,
00057     VARS_NB
00058 };
00059 
00060 typedef struct {
00061     struct SwsContext *sws;     
00062     struct SwsContext *isws[2]; 
00063 
00069     int w, h;
00070     unsigned int flags;         
00071 
00072     int hsub, vsub;             
00073     int slice_y;                
00074     int input_is_pal;           
00075     int interlaced;
00076 
00077     char w_expr[256];           
00078     char h_expr[256];           
00079 } ScaleContext;
00080 
00081 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00082 {
00083     ScaleContext *scale = ctx->priv;
00084     const char *p;
00085 
00086     av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr));
00087     av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr));
00088 
00089     scale->flags = SWS_BILINEAR;
00090     if (args) {
00091         sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);
00092         p = strstr(args,"flags=");
00093         if (p) scale->flags = strtoul(p+6, NULL, 0);
00094         if(strstr(args,"interl=1")){
00095             scale->interlaced=1;
00096         }else if(strstr(args,"interl=-1"))
00097             scale->interlaced=-1;
00098     }
00099 
00100     return 0;
00101 }
00102 
00103 static av_cold void uninit(AVFilterContext *ctx)
00104 {
00105     ScaleContext *scale = ctx->priv;
00106     sws_freeContext(scale->sws);
00107     sws_freeContext(scale->isws[0]);
00108     sws_freeContext(scale->isws[1]);
00109     scale->sws = NULL;
00110 }
00111 
00112 static int query_formats(AVFilterContext *ctx)
00113 {
00114     AVFilterFormats *formats;
00115     enum PixelFormat pix_fmt;
00116     int ret;
00117 
00118     if (ctx->inputs[0]) {
00119         formats = NULL;
00120         for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)
00121             if (   sws_isSupportedInput(pix_fmt)
00122                 && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {
00123                 avfilter_formats_unref(&formats);
00124                 return ret;
00125             }
00126         avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats);
00127     }
00128     if (ctx->outputs[0]) {
00129         formats = NULL;
00130         for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)
00131             if (   (sws_isSupportedOutput(pix_fmt) || pix_fmt == PIX_FMT_PAL8)
00132                 && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {
00133                 avfilter_formats_unref(&formats);
00134                 return ret;
00135             }
00136         avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats);
00137     }
00138 
00139     return 0;
00140 }
00141 
00142 static int config_props(AVFilterLink *outlink)
00143 {
00144     AVFilterContext *ctx = outlink->src;
00145     AVFilterLink *inlink = outlink->src->inputs[0];
00146     enum PixelFormat outfmt = outlink->format;
00147     ScaleContext *scale = ctx->priv;
00148     int64_t w, h;
00149     double var_values[VARS_NB], res;
00150     char *expr;
00151     int ret;
00152 
00153     var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;
00154     var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;
00155     var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
00156     var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
00157     var_values[VAR_A]     = (float) inlink->w / inlink->h;
00158     var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
00159         (float) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
00160     var_values[VAR_DAR]   = var_values[VAR_A] * var_values[VAR_SAR];
00161     var_values[VAR_HSUB]  = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
00162     var_values[VAR_VSUB]  = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
00163 
00164     /* evaluate width and height */
00165     av_expr_parse_and_eval(&res, (expr = scale->w_expr),
00166                            var_names, var_values,
00167                            NULL, NULL, NULL, NULL, NULL, 0, ctx);
00168     scale->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
00169     if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),
00170                                       var_names, var_values,
00171                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
00172         goto fail;
00173     scale->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
00174     /* evaluate again the width, as it may depend on the output height */
00175     if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),
00176                                       var_names, var_values,
00177                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
00178         goto fail;
00179     scale->w = res;
00180 
00181     w = scale->w;
00182     h = scale->h;
00183 
00184     /* sanity check params */
00185     if (w <  -1 || h <  -1) {
00186         av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
00187         return AVERROR(EINVAL);
00188     }
00189     if (w == -1 && h == -1)
00190         scale->w = scale->h = 0;
00191 
00192     if (!(w = scale->w))
00193         w = inlink->w;
00194     if (!(h = scale->h))
00195         h = inlink->h;
00196     if (w == -1)
00197         w = av_rescale(h, inlink->w, inlink->h);
00198     if (h == -1)
00199         h = av_rescale(w, inlink->h, inlink->w);
00200 
00201     if (w > INT_MAX || h > INT_MAX ||
00202         (h * inlink->w) > INT_MAX  ||
00203         (w * inlink->h) > INT_MAX)
00204         av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
00205 
00206     outlink->w = w;
00207     outlink->h = h;
00208 
00209     /* TODO: make algorithm configurable */
00210     av_log(ctx, AV_LOG_INFO, "w:%d h:%d fmt:%s -> w:%d h:%d fmt:%s flags:0x%0x\n",
00211            inlink ->w, inlink ->h, av_pix_fmt_descriptors[ inlink->format].name,
00212            outlink->w, outlink->h, av_pix_fmt_descriptors[outlink->format].name,
00213            scale->flags);
00214 
00215     scale->input_is_pal = av_pix_fmt_descriptors[inlink->format].flags & PIX_FMT_PAL;
00216     if (outfmt == PIX_FMT_PAL8) outfmt = PIX_FMT_BGR8;
00217 
00218     if (scale->sws)
00219         sws_freeContext(scale->sws);
00220     scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,
00221                                 outlink->w, outlink->h, outfmt,
00222                                 scale->flags, NULL, NULL, NULL);
00223     if (scale->isws[0])
00224         sws_freeContext(scale->isws[0]);
00225     scale->isws[0] = sws_getContext(inlink ->w, inlink ->h/2, inlink ->format,
00226                                     outlink->w, outlink->h/2, outfmt,
00227                                     scale->flags, NULL, NULL, NULL);
00228     if (scale->isws[1])
00229         sws_freeContext(scale->isws[1]);
00230     scale->isws[1] = sws_getContext(inlink ->w, inlink ->h/2, inlink ->format,
00231                                     outlink->w, outlink->h/2, outfmt,
00232                                     scale->flags, NULL, NULL, NULL);
00233     if (!scale->sws || !scale->isws[0] || !scale->isws[1])
00234         return AVERROR(EINVAL);
00235 
00236     if (inlink->sample_aspect_ratio.num){
00237         outlink->sample_aspect_ratio = av_mul_q((AVRational){outlink->h * inlink->w, outlink->w * inlink->h}, inlink->sample_aspect_ratio);
00238     } else
00239         outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
00240 
00241     return 0;
00242 
00243 fail:
00244     av_log(NULL, AV_LOG_ERROR,
00245            "Error when evaluating the expression '%s'.\n"
00246            "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
00247            expr, scale->w_expr, scale->h_expr);
00248     return ret;
00249 }
00250 
00251 static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
00252 {
00253     ScaleContext *scale = link->dst->priv;
00254     AVFilterLink *outlink = link->dst->outputs[0];
00255     AVFilterBufferRef *outpicref;
00256 
00257     scale->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;
00258     scale->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;
00259 
00260     outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE|AV_PERM_ALIGN, outlink->w, outlink->h);
00261     avfilter_copy_buffer_ref_props(outpicref, picref);
00262     outpicref->video->w = outlink->w;
00263     outpicref->video->h = outlink->h;
00264 
00265     outlink->out_buf = outpicref;
00266 
00267     av_reduce(&outpicref->video->sample_aspect_ratio.num, &outpicref->video->sample_aspect_ratio.den,
00268               (int64_t)picref->video->sample_aspect_ratio.num * outlink->h * link->w,
00269               (int64_t)picref->video->sample_aspect_ratio.den * outlink->w * link->h,
00270               INT_MAX);
00271 
00272     scale->slice_y = 0;
00273     avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0));
00274 }
00275 
00276 static int scale_slice(AVFilterLink *link, struct SwsContext *sws, int y, int h, int mul, int field)
00277 {
00278     ScaleContext *scale = link->dst->priv;
00279     AVFilterBufferRef *cur_pic = link->cur_buf;
00280     AVFilterBufferRef *out_buf = link->dst->outputs[0]->out_buf;
00281     const uint8_t *in[4];
00282     uint8_t *out[4];
00283     int in_stride[4],out_stride[4];
00284     int i;
00285 
00286     for(i=0; i<4; i++){
00287         int vsub= ((i+1)&2) ? scale->vsub : 0;
00288          in_stride[i] = cur_pic->linesize[i] * mul;
00289         out_stride[i] = out_buf->linesize[i] * mul;
00290          in[i] = cur_pic->data[i] + ((y>>vsub)+field) * cur_pic->linesize[i];
00291         out[i] = out_buf->data[i] +            field  * out_buf->linesize[i];
00292     }
00293     if(scale->input_is_pal){
00294          in[1] = cur_pic->data[1];
00295         out[1] = out_buf->data[1];
00296     }
00297 
00298     return sws_scale(sws, in, in_stride, y/mul, h,
00299                          out,out_stride);
00300 }
00301 
00302 static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
00303 {
00304     ScaleContext *scale = link->dst->priv;
00305     int out_h;
00306 
00307     if (scale->slice_y == 0 && slice_dir == -1)
00308         scale->slice_y = link->dst->outputs[0]->h;
00309 
00310     if(scale->interlaced>0 || (scale->interlaced<0 && link->cur_buf->video->interlaced)){
00311         av_assert0(y%(2<<scale->vsub) == 0);
00312         out_h = scale_slice(link, scale->isws[0], y, (h+1)/2, 2, 0);
00313         out_h+= scale_slice(link, scale->isws[1], y,  h   /2, 2, 1);
00314     }else{
00315         out_h = scale_slice(link, scale->sws, y, h, 1, 0);
00316     }
00317 
00318     if (slice_dir == -1)
00319         scale->slice_y -= out_h;
00320     avfilter_draw_slice(link->dst->outputs[0], scale->slice_y, out_h, slice_dir);
00321     if (slice_dir == 1)
00322         scale->slice_y += out_h;
00323 }
00324 
00325 AVFilter avfilter_vf_scale = {
00326     .name      = "scale",
00327     .description = NULL_IF_CONFIG_SMALL("Scale the input video to width:height size and/or convert the image format."),
00328 
00329     .init      = init,
00330     .uninit    = uninit,
00331 
00332     .query_formats = query_formats,
00333 
00334     .priv_size = sizeof(ScaleContext),
00335 
00336     .inputs    = (const AVFilterPad[]) {{ .name       = "default",
00337                                     .type             = AVMEDIA_TYPE_VIDEO,
00338                                     .start_frame      = start_frame,
00339                                     .draw_slice       = draw_slice,
00340                                     .min_perms        = AV_PERM_READ, },
00341                                   { .name = NULL}},
00342     .outputs   = (const AVFilterPad[]) {{ .name       = "default",
00343                                     .type             = AVMEDIA_TYPE_VIDEO,
00344                                     .config_props     = config_props, },
00345                                   { .name = NULL}},
00346 };