libavfilter/vf_fade.c

   1 /*
   2  * Copyright (c) 2010 Brandon Mintern
   3  * Copyright (c) 2007 Bobby Bingham
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * video fade filter
  25  * based heavily on vf_negate.c by Bobby Bingham
  26  */
  27
  28 #include "libavutil/common.h"
  29 #include "libavutil/pixdesc.h"
  30 #include "avfilter.h"
  31 #include "formats.h"
  32 #include "internal.h"
  33 #include "video.h"
  34
  35 typedef struct {
  36     int factor, fade_per_frame;
  37     unsigned int frame_index, start_frame, stop_frame;
  38     int hsub, vsub, bpp;
  39 } FadeContext;
  40
  41 static av_cold int init(AVFilterContext *ctx, const char *args)
  42 {
  43     FadeContext *fade = ctx->priv;
  44     unsigned int nb_frames;
  45     char in_out[4];
  46
  47     if (!args ||
  48         sscanf(args, " %3[^:]:%u:%u", in_out, &fade->start_frame, &nb_frames) != 3) {
  49         av_log(ctx, AV_LOG_ERROR,
  50                "Expected 3 arguments '(in|out):#:#':'%s'\n", args);
  51         return AVERROR(EINVAL);
  52     }
  53
  54     nb_frames = nb_frames ? nb_frames : 1;
  55     fade->fade_per_frame = (1 << 16) / nb_frames;
  56     if (!strcmp(in_out, "in"))
  57         fade->factor = 0;
  58     else if (!strcmp(in_out, "out")) {
  59         fade->fade_per_frame = -fade->fade_per_frame;
  60         fade->factor = (1 << 16);
  61     } else {
  62         av_log(ctx, AV_LOG_ERROR,
  63                "first argument must be 'in' or 'out':'%s'\n", in_out);
  64         return AVERROR(EINVAL);
  65     }
  66     fade->stop_frame = fade->start_frame + nb_frames;
  67
  68     av_log(ctx, AV_LOG_VERBOSE,
  69            "type:%s start_frame:%d nb_frames:%d\n",
  70            in_out, fade->start_frame, nb_frames);
  71     return 0;
  72 }
  73
  74 static int query_formats(AVFilterContext *ctx)
  75 {
  76     static const enum AVPixelFormat pix_fmts[] = {
  77         AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
  78         AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,
  79         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
  80         AV_PIX_FMT_YUV440P,  AV_PIX_FMT_YUVJ440P,
  81         AV_PIX_FMT_RGB24,    AV_PIX_FMT_BGR24,
  82         AV_PIX_FMT_NONE
  83     };
  84
  85     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
  86     return 0;
  87 }
  88
  89 static int config_props(AVFilterLink *inlink)
  90 {
  91     FadeContext *fade = inlink->dst->priv;
  92     const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(inlink->format);
  93
  94     fade->hsub = pixdesc->log2_chroma_w;
  95     fade->vsub = pixdesc->log2_chroma_h;
  96
  97     fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
  98     return 0;
  99 }
 100
 101 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 102 {
 103     FadeContext *fade = inlink->dst->priv;
 104     uint8_t *p;
 105     int i, j, plane;
 106
 107     if (fade->factor < UINT16_MAX) {
 108         /* luma or rgb plane */
 109         for (i = 0; i < frame->height; i++) {
 110             p = frame->data[0] + i * frame->linesize[0];
 111             for (j = 0; j < inlink->w * fade->bpp; j++) {
 112                 /* fade->factor is using 16 lower-order bits for decimal
 113                  * places. 32768 = 1 << 15, it is an integer representation
 114                  * of 0.5 and is for rounding. */
 115                 *p = (*p * fade->factor + 32768) >> 16;
 116                 p++;
 117             }
 118         }
 119
 120         if (frame->data[1] && frame->data[2]) {
 121             /* chroma planes */
 122             for (plane = 1; plane < 3; plane++) {
 123                 for (i = 0; i < frame->height; i++) {
 124                     p = frame->data[plane] + (i >> fade->vsub) * frame->linesize[plane];
 125                     for (j = 0; j < inlink->w >> fade->hsub; j++) {
 126                         /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
 127                          * representation of 128.5. The .5 is for rounding
 128                          * purposes. */
 129                         *p = ((*p - 128) * fade->factor + 8421367) >> 16;
 130                         p++;
 131                     }
 132                 }
 133             }
 134         }
 135     }
 136
 137     if (fade->frame_index >= fade->start_frame &&
 138         fade->frame_index <= fade->stop_frame)
 139         fade->factor += fade->fade_per_frame;
 140     fade->factor = av_clip_uint16(fade->factor);
 141     fade->frame_index++;
 142
 143     return ff_filter_frame(inlink->dst->outputs[0], frame);
 144 }
 145
 146 static const AVFilterPad avfilter_vf_fade_inputs[] = {
 147     {
 148         .name             = "default",
 149         .type             = AVMEDIA_TYPE_VIDEO,
 150         .config_props     = config_props,
 151         .get_video_buffer = ff_null_get_video_buffer,
 152         .filter_frame     = filter_frame,
 153         .needs_writable   = 1,
 154     },
 155     { NULL }
 156 };
 157
 158 static const AVFilterPad avfilter_vf_fade_outputs[] = {
 159     {
 160         .name = "default",
 161         .type = AVMEDIA_TYPE_VIDEO,
 162     },
 163     { NULL }
 164 };
 165
 166 AVFilter avfilter_vf_fade = {
 167     .name          = "fade",
 168     .description   = NULL_IF_CONFIG_SMALL("Fade in/out input video"),
 169     .init          = init,
 170     .priv_size     = sizeof(FadeContext),
 171     .query_formats = query_formats,
 172
 173     .inputs    = avfilter_vf_fade_inputs,
 174     .outputs   = avfilter_vf_fade_outputs,
 175 };