[FFmpeg-devel] [PATCH] colorbalance filter
Clément Bœsch
ubitux at gmail.com
Mon Apr 15 13:22:52 CEST 2013
On Mon, Apr 15, 2013 at 11:02:34AM +0000, Paul B Mahol wrote:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
> doc/filters.texi | 25 ++++
> libavfilter/Makefile | 1 +
> libavfilter/allfilters.c | 1 +
> libavfilter/vf_colorbalance.c | 282 ++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 309 insertions(+)
> create mode 100644 libavfilter/vf_colorbalance.c
>
[...]
> +static int config_output(AVFilterLink *outlink)
> +{
> + AVFilterContext *ctx = outlink->src;
> + ColorBalanceContext *cb = ctx->priv;
> + AVFilterLink *inlink = ctx->inputs[0];
> + double *add[3], *sub[3];
> + double *coeff[3][3];
> + double *buffer;
> + int i, r, g, b;
> +
> + switch (inlink->format) {
> + case AV_PIX_FMT_RGB24:
> + buffer = av_malloc(256 * 3 * 2 * sizeof(double));
> + if (!buffer)
> + return AVERROR(ENOMEM);
> +
> + for (i = 0; i < 3; i++) {
> + add[i] = buffer + 256 * i;
> + sub[i] = buffer + 256 * (3 + i);
> + }
> +
> + for (i = 0; i < 256; i++) {
> + double low = (1.075 - 1 / (i / 16.0 + 1));
> + double mid = 2.0 / 3.0 * (1 - ((i - 127.0) / 127.0) * ((i - 127.0) / 127.0));
> +
> + add[0][i] = low;
> + add[1][i] = mid;
> + add[2][255 - i] = low;
> + sub[0][255 - i] = low;
> + sub[1][i] = mid;
> + sub[2][i] = low;
> + }
> +
> + coeff[0][0] = cb->cyan_red.shadows > 0 ? add[0] : sub[0];
> + coeff[0][1] = cb->cyan_red.midtones > 0 ? add[1] : sub[1];
> + coeff[0][2] = cb->cyan_red.highlights > 0 ? add[2] : sub[2];
> + coeff[1][0] = cb->magenta_green.shadows > 0 ? add[0] : sub[0];
> + coeff[1][1] = cb->magenta_green.midtones > 0 ? add[1] : sub[1];
> + coeff[1][2] = cb->magenta_green.highlights > 0 ? add[2] : sub[2];
> + coeff[2][0] = cb->yellow_blue.shadows > 0 ? add[0] : sub[0];
> + coeff[2][1] = cb->yellow_blue.midtones > 0 ? add[1] : sub[1];
> + coeff[2][2] = cb->yellow_blue.highlights > 0 ? add[2] : sub[2];
> +
> + for (i = 0; i < 256; i++) {
> + r = g = b = i;
> +
> + r += cb->cyan_red.shadows * coeff[0][0][r];
> + r = av_clip_uint8(r);
> + r += cb->cyan_red.midtones * coeff[0][1][r];
> + r = av_clip_uint8(r);
> + r += cb->cyan_red.highlights * coeff[0][2][r];
> + r = av_clip_uint8(r);
> +
Possibly simpler:
r = av_clip_uint8_t(r + cb->cyan_red.shadows * coeff[0][0][r]);
r = av_clip_uint8_t(r + cb->cyan_red.midtones * coeff[0][1][r]);
r = av_clip_uint8_t(r + cb->cyan_red.highlights * coeff[0][2][r]);
?
> + g += cb->magenta_green.shadows * coeff[1][0][g];
> + g = av_clip_uint8(g);
> + g += cb->magenta_green.midtones * coeff[1][1][g];
> + g = av_clip_uint8(g);
> + g += cb->magenta_green.highlights * coeff[1][2][g];
> + g = av_clip_uint8(g);
> +
> + b += cb->yellow_blue.shadows * coeff[2][0][b];
> + b = av_clip_uint8(b);
> + b += cb->yellow_blue.midtones * coeff[2][1][b];
> + b = av_clip_uint8(b);
> + b += cb->yellow_blue.highlights * coeff[2][2][b];
> + b = av_clip_uint8(b);
> +
> + cb->lookup8[0][i] = r;
> + cb->lookup8[1][i] = g;
> + cb->lookup8[2][i] = b;
> + }
> + break;
> + case AV_PIX_FMT_RGB48:
> + buffer = av_malloc(256 * 256 * 3 * 2 * sizeof(double));
> + if (!buffer)
> + return AVERROR(ENOMEM);
> +
> + for (i = 0; i < 3; i++) {
> + add[i] = buffer + 256 * 256 * i;
> + sub[i] = buffer + 256 * 256 * (3 + i);
> + }
> +
> + for (i = 0; i < 256 * 256; i++) {
> + double low = (100.075 - 100 / (i / 256.0 + 100));
255.0?
> + double mid = 2.0 / 3.0 * (100 - ((i - 32767.0) / 32767.0) * ((i - 32767.0) / 32767.0));
> +
> + add[0][i] = low;
> + add[1][i] = mid;
> + add[2][65535 - i] = low;
> + sub[0][65535 - i] = low;
> + sub[1][i] = mid;
> + sub[2][i] = low;
> + }
> +
> + coeff[0][0] = cb->cyan_red.shadows > 0 ? add[0] : sub[0];
> + coeff[0][1] = cb->cyan_red.midtones > 0 ? add[1] : sub[1];
> + coeff[0][2] = cb->cyan_red.highlights > 0 ? add[2] : sub[2];
> + coeff[1][0] = cb->magenta_green.shadows > 0 ? add[0] : sub[0];
> + coeff[1][1] = cb->magenta_green.midtones > 0 ? add[1] : sub[1];
> + coeff[1][2] = cb->magenta_green.highlights > 0 ? add[2] : sub[2];
> + coeff[2][0] = cb->yellow_blue.shadows > 0 ? add[0] : sub[0];
> + coeff[2][1] = cb->yellow_blue.midtones > 0 ? add[1] : sub[1];
> + coeff[2][2] = cb->yellow_blue.highlights > 0 ? add[2] : sub[2];
> +
> + for (i = 0; i < 256 * 256; i++) {
> + r = g = b = i;
> +
> + r += cb->cyan_red.shadows * coeff[0][0][r];
> + r = av_clip_uint16(r);
> + r += cb->cyan_red.midtones * coeff[0][1][r];
> + r = av_clip_uint16(r);
> + r += cb->cyan_red.highlights * coeff[0][2][r];
> + r = av_clip_uint16(r);
> +
> + g += cb->magenta_green.shadows * coeff[1][0][g];
> + g = av_clip_uint16(g);
> + g += cb->magenta_green.midtones * coeff[1][1][g];
> + g = av_clip_uint16(g);
> + g += cb->magenta_green.highlights * coeff[1][2][g];
> + g = av_clip_uint16(g);
> +
> + b += cb->yellow_blue.shadows * coeff[2][0][b];
> + b = av_clip_uint16(b);
> + b += cb->yellow_blue.midtones * coeff[2][1][b];
> + b = av_clip_uint16(b);
> + b += cb->yellow_blue.highlights * coeff[2][2][b];
> + b = av_clip_uint16(b);
> +
> + cb->lookup16[0][i] = r;
> + cb->lookup16[1][i] = g;
> + cb->lookup16[2][i] = b;
> + }
> + break;
Some parts look definitely factorizable between the two formats.
> + default:
> + av_assert0(0);
> + }
> +
> + av_free(buffer);
> +
> + return 0;
> +}
> +
> +static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
> +{
> + AVFilterContext *ctx = inlink->dst;
> + ColorBalanceContext *cb = ctx->priv;
> + AVFilterLink *outlink = ctx->outputs[0];
> + uint8_t *row = buf->data[0];
> + int i, j;
> +
> + switch (outlink->format) {
> + case AV_PIX_FMT_RGB24:
> + for (i = 0; i < outlink->h; i++) {
> + uint8_t *ptr = row;
> +
> + for (j = 0; j < outlink->w * 3; j += 3) {
> + ptr[j + 0] = cb->lookup8[0][ptr[j + 0]];
> + ptr[j + 1] = cb->lookup8[1][ptr[j + 1]];
> + ptr[j + 2] = cb->lookup8[2][ptr[j + 2]];
> + }
> +
> + row += buf->linesize[0];
> + }
> + break;
> + case AV_PIX_FMT_RGB48:
> + for (i = 0; i < outlink->h; i++) {
> + uint16_t *ptr = (uint16_t *)row;
> +
> + for (j = 0; j < outlink->w * 3; j += 3) {
> + ptr[j + 0] = cb->lookup16[0][ptr[j + 0]];
> + ptr[j + 1] = cb->lookup16[1][ptr[j + 1]];
> + ptr[j + 2] = cb->lookup16[2][ptr[j + 2]];
> + }
> +
> + row += buf->linesize[0];
> + }
> + break;
> + default:
> + av_assert0(0);
> + }
> +
It's a simple LUT table, so you can add a direct path easily.
> + return ff_filter_frame(ctx->outputs[0], buf);
> +}
> +
> +static const AVFilterPad colorbalance_inputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + .filter_frame = filter_frame,
> + .needs_writable = 1,
...and then avoid the need for this.
> + },
> + { NULL }
> +};
> +
> +static const AVFilterPad colorbalance_outputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + .config_props = config_output,
> + },
> + { NULL }
> +};
> +
> +AVFilter avfilter_vf_colorbalance = {
> + .name = "colorbalance",
> + .description = NULL_IF_CONFIG_SMALL("Adjust the color balance."),
> + .priv_size = sizeof(ColorBalanceContext),
> + .query_formats = query_formats,
> + .inputs = colorbalance_inputs,
> + .outputs = colorbalance_outputs,
> + .priv_class = &colorbalance_class,
> +};
A FATE test would be welcome too.
--
Clément B.
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