From e6876c7b7b5524fcb6acadf711cda592687402f7 Mon Sep 17 00:00:00 2001 From: Paul B Mahol Date: Mon, 19 Aug 2013 19:09:58 +0000 Subject: [PATCH] lavfi/hue: use lookup tables Signed-off-by: Paul B Mahol --- libavfilter/vf_hue.c | 79 +++++++++++++++++++++++++++----------------- 1 file changed, 49 insertions(+), 30 deletions(-) diff --git a/libavfilter/vf_hue.c b/libavfilter/vf_hue.c index cc8ac7842e..d066c4075f 100644 --- a/libavfilter/vf_hue.c +++ b/libavfilter/vf_hue.c @@ -73,6 +73,8 @@ typedef struct { int32_t hue_sin; int32_t hue_cos; double var_values[VAR_NB]; + uint8_t lut_u[256][256]; + uint8_t lut_v[256][256]; } HueContext; #define OFFSET(x) offsetof(HueContext, x) @@ -94,12 +96,43 @@ static inline void compute_sin_and_cos(HueContext *hue) /* * Scale the value to the norm of the resulting (U,V) vector, that is * the saturation. - * This will be useful in the process_chrominance function. + * This will be useful in the apply_lut function. */ hue->hue_sin = rint(sin(hue->hue) * (1 << 16) * hue->saturation); hue->hue_cos = rint(cos(hue->hue) * (1 << 16) * hue->saturation); } +static inline void create_chrominance_lut(HueContext *h, const int32_t c, + const int32_t s) +{ + int32_t i, j, u, v, new_u, new_v; + + /* + * If we consider U and V as the components of a 2D vector then its angle + * is the hue and the norm is the saturation + */ + for (i = 0; i < 256; i++) { + for (j = 0; j < 256; j++) { + /* Normalize the components from range [16;140] to [-112;112] */ + u = i - 128; + v = j - 128; + /* + * Apply the rotation of the vector : (c * u) - (s * v) + * (s * u) + (c * v) + * De-normalize the components (without forgetting to scale 128 + * by << 16) + * Finally scale back the result by >> 16 + */ + new_u = ((c * u) - (s * v) + (1 << 15) + (128 << 16)) >> 16; + new_v = ((s * u) + (c * v) + (1 << 15) + (128 << 16)) >> 16; + + /* Prevent a potential overflow */ + h->lut_u[i][j] = av_clip_uint8_c(new_u); + h->lut_v[i][j] = av_clip_uint8_c(new_v); + } + } +} + static int set_expr(AVExpr **pexpr_ptr, char **expr_ptr, const char *expr, const char *option, void *log_ctx) { @@ -202,36 +235,20 @@ static int config_props(AVFilterLink *inlink) return 0; } -static void process_chrominance(uint8_t *udst, uint8_t *vdst, const int dst_linesize, - uint8_t *usrc, uint8_t *vsrc, const int src_linesize, - int w, int h, - const int32_t c, const int32_t s) +static void apply_lut(HueContext *s, + uint8_t *udst, uint8_t *vdst, const int dst_linesize, + uint8_t *usrc, uint8_t *vsrc, const int src_linesize, + int w, int h) { - int32_t u, v, new_u, new_v; int i; - /* - * If we consider U and V as the components of a 2D vector then its angle - * is the hue and the norm is the saturation - */ while (h--) { for (i = 0; i < w; i++) { - /* Normalize the components from range [16;140] to [-112;112] */ - u = usrc[i] - 128; - v = vsrc[i] - 128; - /* - * Apply the rotation of the vector : (c * u) - (s * v) - * (s * u) + (c * v) - * De-normalize the components (without forgetting to scale 128 - * by << 16) - * Finally scale back the result by >> 16 - */ - new_u = ((c * u) - (s * v) + (1 << 15) + (128 << 16)) >> 16; - new_v = ((s * u) + (c * v) + (1 << 15) + (128 << 16)) >> 16; + const int u = usrc[i]; + const int v = vsrc[i]; - /* Prevent a potential overflow */ - udst[i] = av_clip_uint8_c(new_u); - vdst[i] = av_clip_uint8_c(new_v); + udst[i] = s->lut_u[u][v]; + vdst[i] = s->lut_v[u][v]; } usrc += src_linesize; @@ -249,6 +266,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *inpic) HueContext *hue = inlink->dst->priv; AVFilterLink *outlink = inlink->dst->outputs[0]; AVFrame *outpic; + const int32_t old_hue_sin = hue->hue_sin, old_hue_cos = hue->hue_cos; int direct = 0; if (av_frame_is_writable(inpic)) { @@ -292,6 +310,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *inpic) hue->var_values[VAR_T], (int)hue->var_values[VAR_N]); compute_sin_and_cos(hue); + if (old_hue_sin != hue->hue_sin || old_hue_cos != hue->hue_cos) + create_chrominance_lut(hue, hue->hue_cos, hue->hue_sin); if (!direct) { av_image_copy_plane(outpic->data[0], outpic->linesize[0], @@ -303,11 +323,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *inpic) inlink->w, inlink->h); } - process_chrominance(outpic->data[1], outpic->data[2], outpic->linesize[1], - inpic->data[1], inpic->data[2], inpic->linesize[1], - FF_CEIL_RSHIFT(inlink->w, hue->hsub), - FF_CEIL_RSHIFT(inlink->h, hue->vsub), - hue->hue_cos, hue->hue_sin); + apply_lut(hue, outpic->data[1], outpic->data[2], outpic->linesize[1], + inpic->data[1], inpic->data[2], inpic->linesize[1], + FF_CEIL_RSHIFT(inlink->w, hue->hsub), + FF_CEIL_RSHIFT(inlink->h, hue->vsub)); if (!direct) av_frame_free(&inpic);