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| author | Paul B Mahol <onemda@gmail.com> | 2013-05-19 14:30:42 +0000 |
|---|---|---|
| committer | Paul B Mahol <onemda@gmail.com> | 2013-05-19 14:30:42 +0000 |
| commit | 68c4633fa88bfcc36f5b0ae1d34dad47ce928cfe (patch) | |
| tree | f35b24e82a6e54facbbb81d9b4815c2e75053f26 /libavfilter/vf_histogram.c | |
| parent | b154d203b1c280624081a0b52ae27f489ea3333c (diff) | |
| download | ffmpeg-68c4633fa88bfcc36f5b0ae1d34dad47ce928cfe.tar.gz | |
lavfi/histogram: cache log2 of max_hval
Instead of calculating same value over and over again.
Signed-off-by: Paul B Mahol <onemda@gmail.com>
Diffstat (limited to 'libavfilter/vf_histogram.c')
| -rw-r--r-- | libavfilter/vf_histogram.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/libavfilter/vf_histogram.c b/libavfilter/vf_histogram.c index 40afe1f327..f17516e77c 100644 --- a/libavfilter/vf_histogram.c +++ b/libavfilter/vf_histogram.c @@ -39,7 +39,6 @@ typedef struct HistogramContext { const AVClass *class; ///< AVClass context for log and options purpose enum HistogramMode mode; unsigned histogram[256]; - unsigned max_hval; int ncomp; const uint8_t *bg_color; const uint8_t *fg_color; @@ -191,6 +190,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in) case MODE_LEVELS: for (k = 0; k < h->ncomp; k++) { int start = k * (h->level_height + h->scale_height) * h->display_mode; + double max_hval_log; + unsigned max_hval = 0; for (i = 0; i < in->height; i++) { src = in->data[k] + i * in->linesize[k]; @@ -199,15 +200,16 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in) } for (i = 0; i < 256; i++) - h->max_hval = FFMAX(h->max_hval, h->histogram[i]); + max_hval = FFMAX(max_hval, h->histogram[i]); + max_hval_log = log2(max_hval + 1); for (i = 0; i < outlink->w; i++) { int col_height; if (h->levels_mode) - col_height = round(h->level_height * (1. - (log2(h->histogram[i] + 1) / log2(h->max_hval + 1)))); + col_height = round(h->level_height * (1. - (log2(h->histogram[i] + 1) / max_hval_log))); else - col_height = h->level_height - (h->histogram[i] * (int64_t)h->level_height + h->max_hval - 1) / h->max_hval; + col_height = h->level_height - (h->histogram[i] * (int64_t)h->level_height + max_hval - 1) / max_hval; for (j = h->level_height - 1; j >= col_height; j--) { if (h->display_mode) { @@ -222,7 +224,6 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in) } memset(h->histogram, 0, 256 * sizeof(unsigned)); - h->max_hval = 0; } break; case MODE_WAVEFORM: |