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lavfi/hue: use lookup tables 

Signed-off-by: Paul B Mahol <onemda@gmail.com>
This commit is contained in:
Paul B Mahol 2013-08-19 19:09:58 +00:00
parent ca7f637a1e
commit e6876c7b7b
1 changed files with 49 additions and 30 deletions
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79
libavfilter/vf_hue.c
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@ -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);