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/pixdesc.h"
29#include "avfilter.h"
30
31typedef struct {
32    int factor, fade_per_frame;
33    unsigned int frame_index, start_frame, stop_frame;
34    int hsub, vsub, bpp;
35} FadeContext;
36
37static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
38{
39    FadeContext *fade = ctx->priv;
40    unsigned int nb_frames;
41    char in_out[4];
42
43    if (!args ||
44        sscanf(args, " %3[^:]:%u:%u", in_out, &fade->start_frame, &nb_frames) != 3) {
45        av_log(ctx, AV_LOG_ERROR,
46               "Expected 3 arguments '(in|out):#:#':'%s'\n", args);
47        return AVERROR(EINVAL);
48    }
49
50    nb_frames = nb_frames ? nb_frames : 1;
51    fade->fade_per_frame = (1 << 16) / nb_frames;
52    if (!strcmp(in_out, "in"))
53        fade->factor = 0;
54    else if (!strcmp(in_out, "out")) {
55        fade->fade_per_frame = -fade->fade_per_frame;
56        fade->factor = (1 << 16);
57    } else {
58        av_log(ctx, AV_LOG_ERROR,
59               "first argument must be 'in' or 'out':'%s'\n", in_out);
60        return AVERROR(EINVAL);
61    }
62    fade->stop_frame = fade->start_frame + nb_frames;
63
64    av_log(ctx, AV_LOG_INFO,
65           "type:%s start_frame:%d nb_frames:%d\n",
66           in_out, fade->start_frame, nb_frames);
67    return 0;
68}
69
70static int query_formats(AVFilterContext *ctx)
71{
72    static const enum PixelFormat pix_fmts[] = {
73        PIX_FMT_YUV444P,  PIX_FMT_YUV422P,  PIX_FMT_YUV420P,
74        PIX_FMT_YUV411P,  PIX_FMT_YUV410P,
75        PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P,
76        PIX_FMT_YUV440P,  PIX_FMT_YUVJ440P,
77        PIX_FMT_RGB24,    PIX_FMT_BGR24,
78        PIX_FMT_NONE
79    };
80
81    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
82    return 0;
83}
84
85static int config_props(AVFilterLink *inlink)
86{
87    FadeContext *fade = inlink->dst->priv;
88    const AVPixFmtDescriptor *pixdesc = &av_pix_fmt_descriptors[inlink->format];
89
90    fade->hsub = pixdesc->log2_chroma_w;
91    fade->vsub = pixdesc->log2_chroma_h;
92
93    fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
94    return 0;
95}
96
97static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
98{
99    FadeContext *fade = inlink->dst->priv;
100    AVFilterBufferRef *outpic = inlink->cur_buf;
101    uint8_t *p;
102    int i, j, plane;
103
104    if (fade->factor < UINT16_MAX) {
105        /* luma or rgb plane */
106        for (i = 0; i < h; i++) {
107            p = outpic->data[0] + (y+i) * outpic->linesize[0];
108            for (j = 0; j < inlink->w * fade->bpp; j++) {
109                /* fade->factor is using 16 lower-order bits for decimal
110                 * places. 32768 = 1 << 15, it is an integer representation
111                 * of 0.5 and is for rounding. */
112                *p = (*p * fade->factor + 32768) >> 16;
113                p++;
114            }
115        }
116
117        if (outpic->data[1] && outpic->data[2]) {
118            /* chroma planes */
119            for (plane = 1; plane < 3; plane++) {
120                for (i = 0; i < h; i++) {
121                    p = outpic->data[plane] + ((y+i) >> fade->vsub) * outpic->linesize[plane];
122                    for (j = 0; j < inlink->w >> fade->hsub; j++) {
123                        /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
124                         * representation of 128.5. The .5 is for rounding
125                         * purposes. */
126                        *p = ((*p - 128) * fade->factor + 8421367) >> 16;
127                        p++;
128                    }
129                }
130            }
131        }
132    }
133
134    avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
135}
136
137static void end_frame(AVFilterLink *inlink)
138{
139    FadeContext *fade = inlink->dst->priv;
140
141    avfilter_end_frame(inlink->dst->outputs[0]);
142
143    if (fade->frame_index >= fade->start_frame &&
144        fade->frame_index <= fade->stop_frame)
145        fade->factor += fade->fade_per_frame;
146    fade->factor = av_clip_uint16(fade->factor);
147    fade->frame_index++;
148}
149
150AVFilter avfilter_vf_fade = {
151    .name          = "fade",
152    .description   = NULL_IF_CONFIG_SMALL("Fade in/out input video"),
153    .init          = init,
154    .priv_size     = sizeof(FadeContext),
155    .query_formats = query_formats,
156
157    .inputs    = (AVFilterPad[]) {{ .name            = "default",
158                                    .type            = AVMEDIA_TYPE_VIDEO,
159                                    .config_props    = config_props,
160                                    .get_video_buffer = avfilter_null_get_video_buffer,
161                                    .start_frame      = avfilter_null_start_frame,
162                                    .draw_slice      = draw_slice,
163                                    .end_frame       = end_frame,
164                                    .min_perms       = AV_PERM_READ | AV_PERM_WRITE,
165                                    .rej_perms       = AV_PERM_PRESERVE, },
166                                  { .name = NULL}},
167    .outputs   = (AVFilterPad[]) {{ .name            = "default",
168                                    .type            = AVMEDIA_TYPE_VIDEO, },
169                                  { .name = NULL}},
170};
171