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vf_fade: fade to correct CCIR601/709 black level

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Current implementation fades to 0. This implementation fades to 16 for
YUV formats that contain CCIR601/709 video levels. RGB and YUVJ
formats are not altered.

Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
This commit is contained in:
Mark Himsley 2011-11-02 21:39:55 +01:00 committed by Stefano Sabatini
parent f68742bf5b
commit 91dfb73852
1 changed files with 16 additions and 4 deletions
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20
libavfilter/vf_fade.c
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@ -27,11 +27,13 @@
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "internal.h"
typedef struct {
int factor, fade_per_frame;
unsigned int frame_index, start_frame, stop_frame;
int hsub, vsub, bpp;
unsigned int black_level, black_level_scaled;
} FadeContext;
static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
@ -82,6 +84,13 @@ static int query_formats(AVFilterContext *ctx)
return 0;
}
const static enum PixelFormat studio_level_pix_fmts[] = {
PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV420P,
PIX_FMT_YUV411P, PIX_FMT_YUV410P,
PIX_FMT_YUV440P,
PIX_FMT_NONE
};
static int config_props(AVFilterLink *inlink)
{
FadeContext *fade = inlink->dst->priv;
@ -91,6 +100,11 @@ static int config_props(AVFilterLink *inlink)
fade->vsub = pixdesc->log2_chroma_h;
fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
fade->black_level = ff_fmt_is_in(inlink->format, studio_level_pix_fmts) ? 16 : 0;
/* 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;
}
@ -106,10 +120,8 @@ static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
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. 32768 = 1 << 15, it is an integer representation
* of 0.5 and is for rounding. */
*p = (*p * fade->factor + 32768) >> 16;
/* fade->factor is using 16 lower-order bits for decimal places. */
*p = ((*p - fade->black_level) * fade->factor + fade->black_level_scaled) >> 16;
p++;
}
}