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libavfilter/vf_fade.c

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00001 /*
00002  * Copyright (c) 2010 Brandon Mintern
00003  * Copyright (c) 2007 Bobby Bingham
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00028 #include "libavutil/pixdesc.h"
00029 #include "avfilter.h"
00030 
00031 typedef struct {
00032     int factor, fade_per_frame;
00033     unsigned int frame_index, start_frame, stop_frame;
00034     int hsub, vsub, bpp;
00035 } FadeContext;
00036 
00037 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00038 {
00039     FadeContext *fade = ctx->priv;
00040     unsigned int nb_frames;
00041     char in_out[4];
00042 
00043     if (!args ||
00044         sscanf(args, " %3[^:]:%u:%u", in_out, &fade->start_frame, &nb_frames) != 3) {
00045         av_log(ctx, AV_LOG_ERROR,
00046                "Expected 3 arguments '(in|out):#:#':'%s'\n", args);
00047         return AVERROR(EINVAL);
00048     }
00049 
00050     nb_frames = nb_frames ? nb_frames : 1;
00051     fade->fade_per_frame = (1 << 16) / nb_frames;
00052     if (!strcmp(in_out, "in"))
00053         fade->factor = 0;
00054     else if (!strcmp(in_out, "out")) {
00055         fade->fade_per_frame = -fade->fade_per_frame;
00056         fade->factor = (1 << 16);
00057     } else {
00058         av_log(ctx, AV_LOG_ERROR,
00059                "first argument must be 'in' or 'out':'%s'\n", in_out);
00060         return AVERROR(EINVAL);
00061     }
00062     fade->stop_frame = fade->start_frame + nb_frames;
00063 
00064     av_log(ctx, AV_LOG_INFO,
00065            "type:%s start_frame:%d nb_frames:%d\n",
00066            in_out, fade->start_frame, nb_frames);
00067     return 0;
00068 }
00069 
00070 static int query_formats(AVFilterContext *ctx)
00071 {
00072     static const enum PixelFormat pix_fmts[] = {
00073         PIX_FMT_YUV444P,  PIX_FMT_YUV422P,  PIX_FMT_YUV420P,
00074         PIX_FMT_YUV411P,  PIX_FMT_YUV410P,
00075         PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P,
00076         PIX_FMT_YUV440P,  PIX_FMT_YUVJ440P,
00077         PIX_FMT_RGB24,    PIX_FMT_BGR24,
00078         PIX_FMT_NONE
00079     };
00080 
00081     avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
00082     return 0;
00083 }
00084 
00085 static int config_props(AVFilterLink *inlink)
00086 {
00087     FadeContext *fade = inlink->dst->priv;
00088     const AVPixFmtDescriptor *pixdesc = &av_pix_fmt_descriptors[inlink->format];
00089 
00090     fade->hsub = pixdesc->log2_chroma_w;
00091     fade->vsub = pixdesc->log2_chroma_h;
00092 
00093     fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
00094     return 0;
00095 }
00096 
00097 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
00098 {
00099     FadeContext *fade = inlink->dst->priv;
00100     AVFilterBufferRef *outpic = inlink->cur_buf;
00101     uint8_t *p;
00102     int i, j, plane;
00103 
00104     if (fade->factor < UINT16_MAX) {
00105         /* luma or rgb plane */
00106         for (i = 0; i < h; i++) {
00107             p = outpic->data[0] + (y+i) * outpic->linesize[0];
00108             for (j = 0; j < inlink->w * fade->bpp; j++) {
00109                 /* fade->factor is using 16 lower-order bits for decimal
00110                  * places. 32768 = 1 << 15, it is an integer representation
00111                  * of 0.5 and is for rounding. */
00112                 *p = (*p * fade->factor + 32768) >> 16;
00113                 p++;
00114             }
00115         }
00116 
00117         if (outpic->data[1] && outpic->data[2]) {
00118             /* chroma planes */
00119             for (plane = 1; plane < 3; plane++) {
00120                 for (i = 0; i < h; i++) {
00121                     p = outpic->data[plane] + ((y+i) >> fade->vsub) * outpic->linesize[plane];
00122                     for (j = 0; j < inlink->w >> fade->hsub; j++) {
00123                         /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
00124                          * representation of 128.5. The .5 is for rounding
00125                          * purposes. */
00126                         *p = ((*p - 128) * fade->factor + 8421367) >> 16;
00127                         p++;
00128                     }
00129                 }
00130             }
00131         }
00132     }
00133 
00134     avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
00135 }
00136 
00137 static void end_frame(AVFilterLink *inlink)
00138 {
00139     FadeContext *fade = inlink->dst->priv;
00140 
00141     avfilter_end_frame(inlink->dst->outputs[0]);
00142 
00143     if (fade->frame_index >= fade->start_frame &&
00144         fade->frame_index <= fade->stop_frame)
00145         fade->factor += fade->fade_per_frame;
00146     fade->factor = av_clip_uint16(fade->factor);
00147     fade->frame_index++;
00148 }
00149 
00150 AVFilter avfilter_vf_fade = {
00151     .name          = "fade",
00152     .description   = NULL_IF_CONFIG_SMALL("Fade in/out input video"),
00153     .init          = init,
00154     .priv_size     = sizeof(FadeContext),
00155     .query_formats = query_formats,
00156 
00157     .inputs    = (AVFilterPad[]) {{ .name            = "default",
00158                                     .type            = AVMEDIA_TYPE_VIDEO,
00159                                     .config_props    = config_props,
00160                                     .get_video_buffer = avfilter_null_get_video_buffer,
00161                                     .start_frame      = avfilter_null_start_frame,
00162                                     .draw_slice      = draw_slice,
00163                                     .end_frame       = end_frame,
00164                                     .min_perms       = AV_PERM_READ | AV_PERM_WRITE,
00165                                     .rej_perms       = AV_PERM_PRESERVE, },
00166                                   { .name = NULL}},
00167     .outputs   = (AVFilterPad[]) {{ .name            = "default",
00168                                     .type            = AVMEDIA_TYPE_VIDEO, },
00169                                   { .name = NULL}},
00170 };
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