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libavfilter/vf_overlay.c

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00001 /*
00002  * Copyright (c) 2010 Stefano Sabatini
00003  * Copyright (c) 2010 Baptiste Coudurier
00004  * Copyright (c) 2007 Bobby Bingham
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * FFmpeg is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with FFmpeg; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00028 #include "avfilter.h"
00029 #include "libavutil/eval.h"
00030 #include "libavutil/avstring.h"
00031 #include "libavutil/pixdesc.h"
00032 #include "libavutil/imgutils.h"
00033 #include "internal.h"
00034 
00035 static const char *var_names[] = {
00036     "E",
00037     "PHI",
00038     "PI",
00039     "main_w",    "W", 
00040     "main_h",    "H", 
00041     "overlay_w", "w", 
00042     "overlay_h", "h", 
00043     NULL
00044 };
00045 
00046 enum var_name {
00047     VAR_E,
00048     VAR_PHI,
00049     VAR_PI,
00050     VAR_MAIN_W,    VAR_MW,
00051     VAR_MAIN_H,    VAR_MH,
00052     VAR_OVERLAY_W, VAR_OW,
00053     VAR_OVERLAY_H, VAR_OH,
00054     VAR_VARS_NB
00055 };
00056 
00057 #define MAIN    0
00058 #define OVERLAY 1
00059 
00060 typedef struct {
00061     int x, y;                   
00062 
00063     AVFilterBufferRef *overpicref;
00064 
00065     int max_plane_step[4];      
00066     int hsub, vsub;             
00067 
00068     char x_expr[256], y_expr[256];
00069 } OverlayContext;
00070 
00071 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00072 {
00073     OverlayContext *over = ctx->priv;
00074 
00075     av_strlcpy(over->x_expr, "0", sizeof(over->x_expr));
00076     av_strlcpy(over->y_expr, "0", sizeof(over->y_expr));
00077 
00078     if (args)
00079         sscanf(args, "%255[^:]:%255[^:]", over->x_expr, over->y_expr);
00080 
00081     return 0;
00082 }
00083 
00084 static av_cold void uninit(AVFilterContext *ctx)
00085 {
00086     OverlayContext *over = ctx->priv;
00087 
00088     if (over->overpicref)
00089         avfilter_unref_buffer(over->overpicref);
00090 }
00091 
00092 static int query_formats(AVFilterContext *ctx)
00093 {
00094     const enum PixelFormat inout_pix_fmts[] = { PIX_FMT_YUV420P,  PIX_FMT_NONE };
00095     const enum PixelFormat blend_pix_fmts[] = { PIX_FMT_YUVA420P, PIX_FMT_NONE };
00096     AVFilterFormats *inout_formats = avfilter_make_format_list(inout_pix_fmts);
00097     AVFilterFormats *blend_formats = avfilter_make_format_list(blend_pix_fmts);
00098 
00099     avfilter_formats_ref(inout_formats, &ctx->inputs [MAIN   ]->out_formats);
00100     avfilter_formats_ref(blend_formats, &ctx->inputs [OVERLAY]->out_formats);
00101     avfilter_formats_ref(inout_formats, &ctx->outputs[MAIN   ]->in_formats );
00102 
00103     return 0;
00104 }
00105 
00106 static int config_input_main(AVFilterLink *inlink)
00107 {
00108     OverlayContext *over = inlink->dst->priv;
00109     const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
00110 
00111     av_image_fill_max_pixsteps(over->max_plane_step, NULL, pix_desc);
00112     over->hsub = pix_desc->log2_chroma_w;
00113     over->vsub = pix_desc->log2_chroma_h;
00114 
00115     return 0;
00116 }
00117 
00118 static int config_input_overlay(AVFilterLink *inlink)
00119 {
00120     AVFilterContext *ctx  = inlink->dst;
00121     OverlayContext  *over = inlink->dst->priv;
00122     char *expr;
00123     double var_values[VAR_VARS_NB], res;
00124     int ret;
00125 
00126     /* Finish the configuration by evaluating the expressions
00127        now when both inputs are configured. */
00128     var_values[VAR_E  ] = M_E;
00129     var_values[VAR_PHI] = M_PHI;
00130     var_values[VAR_PI ] = M_PI;
00131 
00132     var_values[VAR_MAIN_W   ] = var_values[VAR_MW] = ctx->inputs[MAIN   ]->w;
00133     var_values[VAR_MAIN_H   ] = var_values[VAR_MH] = ctx->inputs[MAIN   ]->h;
00134     var_values[VAR_OVERLAY_W] = var_values[VAR_OW] = ctx->inputs[OVERLAY]->w;
00135     var_values[VAR_OVERLAY_H] = var_values[VAR_OH] = ctx->inputs[OVERLAY]->h;
00136 
00137     if ((ret = av_expr_parse_and_eval(&res, (expr = over->x_expr), var_names, var_values,
00138                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
00139         goto fail;
00140     over->x = res;
00141     if ((ret = av_expr_parse_and_eval(&res, (expr = over->y_expr), var_names, var_values,
00142                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)))
00143         goto fail;
00144     over->y = res;
00145     /* x may depend on y */
00146     if ((ret = av_expr_parse_and_eval(&res, (expr = over->x_expr), var_names, var_values,
00147                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
00148         goto fail;
00149     over->x = res;
00150 
00151     av_log(ctx, AV_LOG_INFO,
00152            "main w:%d h:%d fmt:%s overlay x:%d y:%d w:%d h:%d fmt:%s\n",
00153            ctx->inputs[MAIN]->w, ctx->inputs[MAIN]->h,
00154            av_pix_fmt_descriptors[ctx->inputs[MAIN]->format].name,
00155            over->x, over->y,
00156            ctx->inputs[OVERLAY]->w, ctx->inputs[OVERLAY]->h,
00157            av_pix_fmt_descriptors[ctx->inputs[OVERLAY]->format].name);
00158 
00159     if (over->x < 0 || over->y < 0 ||
00160         over->x + var_values[VAR_OVERLAY_W] > var_values[VAR_MAIN_W] ||
00161         over->y + var_values[VAR_OVERLAY_H] > var_values[VAR_MAIN_H]) {
00162         av_log(ctx, AV_LOG_ERROR,
00163                "Overlay area (%d,%d)<->(%d,%d) not within the main area (0,0)<->(%d,%d) or zero-sized\n",
00164                over->x, over->y,
00165                (int)(over->x + var_values[VAR_OVERLAY_W]),
00166                (int)(over->y + var_values[VAR_OVERLAY_H]),
00167                (int)var_values[VAR_MAIN_W], (int)var_values[VAR_MAIN_H]);
00168         return AVERROR(EINVAL);
00169     }
00170     return 0;
00171 
00172 fail:
00173     av_log(NULL, AV_LOG_ERROR,
00174            "Error when evaluating the expression '%s'\n", expr);
00175     return ret;
00176 }
00177 
00178 static int config_output(AVFilterLink *outlink)
00179 {
00180     AVFilterContext *ctx = outlink->src;
00181     int exact;
00182     // common timebase computation:
00183     AVRational tb1 = ctx->inputs[MAIN   ]->time_base;
00184     AVRational tb2 = ctx->inputs[OVERLAY]->time_base;
00185     AVRational *tb = &ctx->outputs[0]->time_base;
00186     exact = av_reduce(&tb->num, &tb->den,
00187                       av_gcd((int64_t)tb1.num * tb2.den,
00188                              (int64_t)tb2.num * tb1.den),
00189                       (int64_t)tb1.den * tb2.den, INT_MAX);
00190     av_log(ctx, AV_LOG_INFO,
00191            "main_tb:%d/%d overlay_tb:%d/%d -> tb:%d/%d exact:%d\n",
00192            tb1.num, tb1.den, tb2.num, tb2.den, tb->num, tb->den, exact);
00193     if (!exact)
00194         av_log(ctx, AV_LOG_WARNING,
00195                "Timestamp conversion inexact, timestamp information loss may occurr\n");
00196 
00197     outlink->w = ctx->inputs[MAIN]->w;
00198     outlink->h = ctx->inputs[MAIN]->h;
00199 
00200     return 0;
00201 }
00202 
00203 static AVFilterBufferRef *get_video_buffer(AVFilterLink *link, int perms, int w, int h)
00204 {
00205     return avfilter_get_video_buffer(link->dst->outputs[0], perms, w, h);
00206 }
00207 
00208 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
00209 {
00210     AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
00211     AVFilterContext *ctx = inlink->dst;
00212     OverlayContext *over = ctx->priv;
00213 
00214     inlink->dst->outputs[0]->out_buf = outpicref;
00215     outpicref->pts = av_rescale_q(outpicref->pts, ctx->inputs[MAIN]->time_base,
00216                                   ctx->outputs[0]->time_base);
00217 
00218     if (!over->overpicref || over->overpicref->pts < outpicref->pts) {
00219         AVFilterBufferRef *old = over->overpicref;
00220         over->overpicref = NULL;
00221         avfilter_request_frame(ctx->inputs[OVERLAY]);
00222         if (over->overpicref) {
00223             if (old)
00224                 avfilter_unref_buffer(old);
00225         } else
00226             over->overpicref = old;
00227     }
00228 
00229     avfilter_start_frame(inlink->dst->outputs[0], outpicref);
00230 }
00231 
00232 static void start_frame_overlay(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
00233 {
00234     AVFilterContext *ctx = inlink->dst;
00235     OverlayContext *over = ctx->priv;
00236 
00237     over->overpicref = inpicref;
00238     over->overpicref->pts = av_rescale_q(inpicref->pts, ctx->inputs[OVERLAY]->time_base,
00239                                          ctx->outputs[0]->time_base);
00240 }
00241 
00242 static void blend_slice(AVFilterContext *ctx,
00243                         AVFilterBufferRef *dst, AVFilterBufferRef *src,
00244                         int x, int y, int w, int h,
00245                         int slice_y, int slice_w, int slice_h)
00246 {
00247     OverlayContext *over = ctx->priv;
00248     int i, j, k;
00249     int width, height;
00250     int overlay_end_y = y+h;
00251     int slice_end_y = slice_y+slice_h;
00252     int end_y, start_y;
00253 
00254     width = FFMIN(slice_w - x, w);
00255     end_y = FFMIN(slice_end_y, overlay_end_y);
00256     start_y = FFMAX(y, slice_y);
00257     height = end_y - start_y;
00258 
00259     if (dst->format == PIX_FMT_BGR24 || dst->format == PIX_FMT_RGB24) {
00260         uint8_t *dp = dst->data[0] + x * 3 + start_y * dst->linesize[0];
00261         uint8_t *sp = src->data[0];
00262         int b = dst->format == PIX_FMT_BGR24 ? 2 : 0;
00263         int r = dst->format == PIX_FMT_BGR24 ? 0 : 2;
00264         if (slice_y > y)
00265             sp += (slice_y - y) * src->linesize[0];
00266         for (i = 0; i < height; i++) {
00267             uint8_t *d = dp, *s = sp;
00268             for (j = 0; j < width; j++) {
00269                 d[r] = (d[r] * (0xff - s[3]) + s[0] * s[3] + 128) >> 8;
00270                 d[1] = (d[1] * (0xff - s[3]) + s[1] * s[3] + 128) >> 8;
00271                 d[b] = (d[b] * (0xff - s[3]) + s[2] * s[3] + 128) >> 8;
00272                 d += 3;
00273                 s += 4;
00274             }
00275             dp += dst->linesize[0];
00276             sp += src->linesize[0];
00277         }
00278     } else {
00279         for (i = 0; i < 3; i++) {
00280             int hsub = i ? over->hsub : 0;
00281             int vsub = i ? over->vsub : 0;
00282             uint8_t *dp = dst->data[i] + (x >> hsub) +
00283                 (start_y >> vsub) * dst->linesize[i];
00284             uint8_t *sp = src->data[i];
00285             uint8_t *ap = src->data[3];
00286             int wp = FFALIGN(width, 1<<hsub) >> hsub;
00287             int hp = FFALIGN(height, 1<<vsub) >> vsub;
00288             if (slice_y > y) {
00289                 sp += ((slice_y - y) >> vsub) * src->linesize[i];
00290                 ap += (slice_y - y) * src->linesize[3];
00291             }
00292             for (j = 0; j < hp; j++) {
00293                 uint8_t *d = dp, *s = sp, *a = ap;
00294                 for (k = 0; k < wp; k++) {
00295                     // average alpha for color components, improve quality
00296                     int alpha_v, alpha_h, alpha;
00297                     if (hsub && vsub && j+1 < hp && k+1 < wp) {
00298                         alpha = (a[0] + a[src->linesize[3]] +
00299                                  a[1] + a[src->linesize[3]+1]) >> 2;
00300                     } else if (hsub || vsub) {
00301                         alpha_h = hsub && k+1 < wp ?
00302                             (a[0] + a[1]) >> 1 : a[0];
00303                         alpha_v = vsub && j+1 < hp ?
00304                             (a[0] + a[src->linesize[3]]) >> 1 : a[0];
00305                         alpha = (alpha_v + alpha_h) >> 1;
00306                     } else
00307                         alpha = a[0];
00308                     *d = (*d * (0xff - alpha) + *s++ * alpha + 128) >> 8;
00309                     d++;
00310                     a += 1 << hsub;
00311                 }
00312                 dp += dst->linesize[i];
00313                 sp += src->linesize[i];
00314                 ap += (1 << vsub) * src->linesize[3];
00315             }
00316         }
00317     }
00318 }
00319 
00320 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
00321 {
00322     AVFilterContext *ctx = inlink->dst;
00323     AVFilterLink *outlink = ctx->outputs[0];
00324     AVFilterBufferRef *outpicref = outlink->out_buf;
00325     OverlayContext *over = ctx->priv;
00326 
00327     if (over->overpicref &&
00328         !(over->x >= outpicref->video->w || over->y >= outpicref->video->h ||
00329           y+h < over->y || y >= over->y + over->overpicref->video->h)) {
00330         blend_slice(ctx, outpicref, over->overpicref, over->x, over->y,
00331                     over->overpicref->video->w, over->overpicref->video->h,
00332                     y, outpicref->video->w, h);
00333     }
00334     avfilter_draw_slice(outlink, y, h, slice_dir);
00335 }
00336 
00337 static void end_frame(AVFilterLink *inlink)
00338 {
00339     avfilter_end_frame(inlink->dst->outputs[0]);
00340     avfilter_unref_buffer(inlink->cur_buf);
00341 }
00342 
00343 static void null_draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir) { }
00344 
00345 static void null_end_frame(AVFilterLink *inlink) { }
00346 
00347 AVFilter avfilter_vf_overlay = {
00348     .name      = "overlay",
00349     .description = NULL_IF_CONFIG_SMALL("Overlay a video source on top of the input."),
00350 
00351     .init      = init,
00352     .uninit    = uninit,
00353 
00354     .priv_size = sizeof(OverlayContext),
00355 
00356     .query_formats = query_formats,
00357 
00358     .inputs    = (AVFilterPad[]) {{ .name            = "main",
00359                                     .type            = AVMEDIA_TYPE_VIDEO,
00360                                     .start_frame     = start_frame,
00361                                     .get_video_buffer= get_video_buffer,
00362                                     .config_props    = config_input_main,
00363                                     .draw_slice      = draw_slice,
00364                                     .end_frame       = end_frame,
00365                                     .min_perms       = AV_PERM_READ,
00366                                     .rej_perms       = AV_PERM_REUSE2|AV_PERM_PRESERVE, },
00367                                   { .name            = "overlay",
00368                                     .type            = AVMEDIA_TYPE_VIDEO,
00369                                     .start_frame     = start_frame_overlay,
00370                                     .config_props    = config_input_overlay,
00371                                     .draw_slice      = null_draw_slice,
00372                                     .end_frame       = null_end_frame,
00373                                     .min_perms       = AV_PERM_READ,
00374                                     .rej_perms       = AV_PERM_REUSE2, },
00375                                   { .name = NULL}},
00376     .outputs   = (AVFilterPad[]) {{ .name            = "default",
00377                                     .type            = AVMEDIA_TYPE_VIDEO,
00378                                     .config_props    = config_output, },
00379                                   { .name = NULL}},
00380 };

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