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vf_fade: add alpha option and alpha fading support

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Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
pull/2/head
Mark Himsley 13 years ago committed by Stefano Sabatini
parent 0d602615ab
commit 8c1fb50d07
3 changed files with 71 additions and 13 deletions
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  1. 6
      doc/filters.texi
  2. 2
      libavfilter/avfilter.h
  3. 76
      libavfilter/vf_fade.c

6
doc/filters.texi
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@ -1166,6 +1166,9 @@ See @var{start_frame}.
@item nb_frames, n
See @var{nb_frames}.
@item alpha
If set to 1, fade only alpha channel, if one exists on the input.
Default value is 0.
@end table
A few usage examples follow, usable too as test scenarios.
@ -1181,6 +1184,9 @@ fade=in:0:25, fade=out:975:25
# make first 5 frames black, then fade in from frame 5-24
fade=in:5:20
# fade in alpha over first 25 frames of video
fade=in:0:25:alpha=1
@end example
@section fieldorder

2
libavfilter/avfilter.h
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@ -30,7 +30,7 @@
#define LIBAVFILTER_VERSION_MAJOR 2
#define LIBAVFILTER_VERSION_MINOR 47
#define LIBAVFILTER_VERSION_MICRO 1
#define LIBAVFILTER_VERSION_MICRO 2
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \

76
libavfilter/vf_fade.c
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@ -33,12 +33,24 @@
#include "drawutils.h"
#include "internal.h"
#define R 0
#define G 1
#define B 2
#define A 3
#define Y 0
#define U 1
#define V 2
typedef struct {
const AVClass *class;
int factor, fade_per_frame;
unsigned int frame_index, start_frame, stop_frame, nb_frames;
int hsub, vsub, bpp;
unsigned int black_level, black_level_scaled;
uint8_t is_packed_rgb;
uint8_t rgba_map[4];
int alpha;
char *type;
} FadeContext;
@ -52,6 +64,7 @@ static const AVOption fade_options[] = {
{ "s", "set expression of frame to start fading", OFFSET(start_frame), AV_OPT_TYPE_INT, {.dbl = 0 }, 0, INT_MAX },
{ "nb_frames", "set expression for fade duration in frames", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.dbl = 25 }, 0, INT_MAX },
{ "n", "set expression for fade duration in frames", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.dbl = 25 }, 0, INT_MAX },
{ "alpha", "fade alpha if it is available on the input", OFFSET(alpha), AV_OPT_TYPE_INT, {.dbl = 0 }, 0, 1 },
{NULL},
};
@ -119,8 +132,8 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
fade->stop_frame = fade->start_frame + fade->nb_frames;
av_log(ctx, AV_LOG_INFO,
"type:%s start_frame:%d nb_frames:%d\n",
fade->type, fade->start_frame, fade->nb_frames);
"type:%s start_frame:%d nb_frames:%d alpha:%d\n",
fade->type, fade->start_frame, fade->nb_frames, fade->alpha);
end:
av_free(args1);
@ -141,7 +154,10 @@ static int query_formats(AVFilterContext *ctx)
PIX_FMT_YUV411P, PIX_FMT_YUV410P,
PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P,
PIX_FMT_YUV440P, PIX_FMT_YUVJ440P,
PIX_FMT_YUVA420P,
PIX_FMT_RGB24, PIX_FMT_BGR24,
PIX_FMT_ARGB, PIX_FMT_ABGR,
PIX_FMT_RGBA, PIX_FMT_BGRA,
PIX_FMT_NONE
};
@ -156,6 +172,13 @@ const static enum PixelFormat studio_level_pix_fmts[] = {
PIX_FMT_NONE
};
static enum PixelFormat alpha_pix_fmts[] = {
PIX_FMT_YUVA420P,
PIX_FMT_ARGB, PIX_FMT_ABGR,
PIX_FMT_RGBA, PIX_FMT_BGRA,
PIX_FMT_NONE
};
static int config_props(AVFilterLink *inlink)
{
FadeContext *fade = inlink->dst->priv;
@ -165,14 +188,37 @@ static int config_props(AVFilterLink *inlink)
fade->vsub = pixdesc->log2_chroma_h;
fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
fade->alpha = fade->alpha ? ff_fmt_is_in(inlink->format, alpha_pix_fmts) : 0;
fade->is_packed_rgb = ff_fill_rgba_map(fade->rgba_map, inlink->format) >= 0;
fade->black_level = ff_fmt_is_in(inlink->format, studio_level_pix_fmts) ? 16 : 0;
/* CCIR601/709 black level unless input is RGB or has alpha */
fade->black_level =
ff_fmt_is_in(inlink->format, studio_level_pix_fmts) || fade->alpha ? 0 : 16;
/* 32768 = 1 << 15, it is an integer representation
* of 0.5 and is for rounding. */
fade->black_level_scaled = (fade->black_level << 16) + 32768;
return 0;
}
static void fade_plane(int y, int h, int w,
int fade_factor, int black_level, int black_level_scaled,
uint8_t offset, uint8_t step, int bytes_per_plane,
uint8_t *data, int line_size)
{
uint8_t *p;
int i, j;
/* luma, alpha or rgb plane */
for (i = 0; i < h; i++) {
p = data + offset + (y+i) * line_size;
for (j = 0; j < w * bytes_per_plane; j++) {
/* fade->factor is using 16 lower-order bits for decimal places. */
*p = ((*p - black_level) * fade_factor + black_level_scaled) >> 16;
p+=step;
}
}
}
static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
{
FadeContext *fade = inlink->dst->priv;
@ -181,16 +227,21 @@ static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
int i, j, plane;
if (fade->factor < UINT16_MAX) {
if (fade->alpha) {
// alpha only
plane = fade->is_packed_rgb ? 0 : A; // alpha is on plane 0 for packed formats
// or plane 3 for planar formats
fade_plane(y, h, inlink->w,
fade->factor, fade->black_level, fade->black_level_scaled,
fade->is_packed_rgb ? fade->rgba_map[A] : 0, // alpha offset for packed formats
fade->is_packed_rgb ? 4 : 1, // pixstep for 8 bit packed formats
1, outpic->data[plane], outpic->linesize[plane]);
} else {
/* luma or rgb plane */
for (i = 0; i < h; i++) {
p = outpic->data[0] + (y+i) * outpic->linesize[0];
for (j = 0; j < inlink->w * fade->bpp; j++) {
/* fade->factor is using 16 lower-order bits for decimal places. */
*p = ((*p - fade->black_level) * fade->factor + fade->black_level_scaled) >> 16;
p++;
}
}
fade_plane(y, h, inlink->w,
fade->factor, fade->black_level, fade->black_level_scaled,
0, 1, // offset & pixstep for Y plane or RGB packed format
fade->bpp, outpic->data[0], outpic->linesize[0]);
if (outpic->data[1] && outpic->data[2]) {
/* chroma planes */
for (plane = 1; plane < 3; plane++) {
@ -206,6 +257,7 @@ static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
}
}
}
}
}
avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);

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