@@ -14483,6 +14483,34 @@ Possible value are:

 @item 2020_ncl

 @item 2020_cl

 @end table

+

+@item chromal, c

+Set the output chroma location.

+

+Possible values are:

+@table @var

+@item input

+@item left

+@item center

+@item topleft

+@item top

+@item bottomleft

+@item bottom

+@end table

+

+@item chromalin, cin

+Set the input chroma location.

+

+Possible values are:

+@table @var

+@item input

+@item left

+@item center

+@item topleft

+@item top

+@item bottomleft

+@item bottom

+@end table

 @end table

 The values of the @option{w} and @option{h} options are expressions

@@ -88,10 +88,12 @@ typedef struct ZScaleContext {

     int trc;

     int primaries;

     int range;

+    int chromal;

     int colorspace_in;

     int trc_in;

     int primaries_in;

     int range_in;

+    int chromal_in;

     char *size_str;

     char *w_expr;               ///< width  expression string

@@ -116,6 +118,7 @@ typedef struct ZScaleContext {

     enum AVColorTransferCharacteristic in_trc, out_trc;

     enum AVColorPrimaries in_primaries, out_primaries;

     enum AVColorRange in_range, out_range;

+    enum AVChromaLocation in_chromal, out_chromal;

 } ZScaleContext;

 static av_cold int init_dict(AVFilterContext *ctx, AVDictionary **opts)

@@ -316,6 +319,26 @@ static int print_zimg_error(AVFilterContext *ctx)

     return err_code;

 }

+static int convert_chroma_location(enum AVChromaLocation chroma_location)

+{

+    switch (chroma_location) {

+    case AVCHROMA_LOC_UNSPECIFIED:

+    case AVCHROMA_LOC_LEFT:

+        return ZIMG_CHROMA_LEFT;

+    case AVCHROMA_LOC_CENTER:

+        return ZIMG_CHROMA_CENTER;

+    case AVCHROMA_LOC_TOPLEFT:

+        return ZIMG_CHROMA_TOP_LEFT;

+    case AVCHROMA_LOC_TOP:

+        return ZIMG_CHROMA_TOP;

+    case AVCHROMA_LOC_BOTTOMLEFT:

+        return ZIMG_CHROMA_BOTTOM_LEFT;

+    case AVCHROMA_LOC_BOTTOM:

+        return ZIMG_CHROMA_BOTTOM;

+    }

+    return ZIMG_CHROMA_LEFT;

+}

+

 static int convert_matrix(enum AVColorSpace colorspace)

 {

     switch (colorspace) {

@@ -420,7 +443,9 @@ static int filter_frame(AVFilterLink *link, AVFrame *in)

        || s->out_colorspace != out->colorspace

        || s->out_trc  != out->color_trc

        || s->out_primaries != out->color_primaries

-       || s->out_range != out->color_range) {

+       || s->out_range != out->color_range

+       || s->in_chromal != in->chroma_location

+       || s->out_chromal != out->chroma_location) {

         snprintf(buf, sizeof(buf)-1, "%d", outlink->w);

         av_opt_set(s, "w", buf, 0);

         snprintf(buf, sizeof(buf)-1, "%d", outlink->h);

@@ -456,6 +481,7 @@ static int filter_frame(AVFilterLink *link, AVFrame *in)

         s->src_format.transfer_characteristics = s->trc_in == - 1 ? convert_trc(in->color_trc) : s->trc_in;

         s->src_format.color_primaries = s->primaries_in == -1 ? convert_primaries(in->color_primaries) : s->primaries_in;

         s->src_format.pixel_range = (desc->flags & AV_PIX_FMT_FLAG_RGB) ? ZIMG_RANGE_FULL : s->range_in == -1 ? convert_range(in->color_range) : s->range_in;

+        s->src_format.chroma_location = s->chromal_in == -1 ? convert_chroma_location(in->chroma_location) : s->chromal_in;

         s->dst_format.width = out->width;

         s->dst_format.height = out->height;

@@ -468,6 +494,7 @@ static int filter_frame(AVFilterLink *link, AVFrame *in)

         s->dst_format.transfer_characteristics = s->trc == -1 ? convert_trc(out->color_trc) : s->trc;

         s->dst_format.color_primaries = s->primaries == -1 ? convert_primaries(out->color_primaries) : s->primaries;

         s->dst_format.pixel_range = (odesc->flags & AV_PIX_FMT_FLAG_RGB) ? ZIMG_RANGE_FULL : s->range == -1 ? convert_range(out->color_range) : s->range;

+        s->dst_format.chroma_location = s->chromal == -1 ? convert_chroma_location(out->chroma_location) : s->chromal;

         if (s->colorspace != -1)

             out->colorspace = (int)s->dst_format.matrix_coefficients;

@@ -481,6 +508,9 @@ static int filter_frame(AVFilterLink *link, AVFrame *in)

         if (s->trc != -1)

             out->color_trc = (int)s->dst_format.transfer_characteristics;

+        if (s->chromal != -1)

+            out->chroma_location = (int)s->dst_format.chroma_location - 1;

+

         zimg_filter_graph_free(s->graph);

         s->graph = zimg_filter_graph_build(&s->src_format, &s->dst_format, &s->params);

         if (!s->graph) {

@@ -705,6 +735,17 @@ static const AVOption zscale_options[] = {

     { "tin",        "set input transfer characteristic", OFFSET(trc_in), AV_OPT_TYPE_INT, {.i64 = -1}, -1, ZIMG_TRANSFER_2020_12, FLAGS, "transfer" },

     { "matrixin", "set input colorspace matrix", OFFSET(colorspace_in), AV_OPT_TYPE_INT, {.i64 = -1}, -1, ZIMG_MATRIX_2020_CL, FLAGS, "matrix" },

     { "min",      "set input colorspace matrix", OFFSET(colorspace_in), AV_OPT_TYPE_INT, {.i64 = -1}, -1, ZIMG_MATRIX_2020_CL, FLAGS, "matrix" },

+    { "chromal",  "set output chroma location", OFFSET(chromal), AV_OPT_TYPE_INT, {.i64 = -1}, -1, ZIMG_CHROMA_BOTTOM, FLAGS, "chroma" },

+    { "c",        "set output chroma location", OFFSET(chromal), AV_OPT_TYPE_INT, {.i64 = -1}, -1, ZIMG_CHROMA_BOTTOM, FLAGS, "chroma" },

+    {     "input",     0, 0, AV_OPT_TYPE_CONST, {.i64 = -1},                       0, 0, FLAGS, "chroma" },

+    {     "left",      0, 0, AV_OPT_TYPE_CONST, {.i64 = ZIMG_CHROMA_LEFT},         0, 0, FLAGS, "chroma" },

+    {     "center",    0, 0, AV_OPT_TYPE_CONST, {.i64 = ZIMG_CHROMA_CENTER},       0, 0, FLAGS, "chroma" },

+    {     "topleft",   0, 0, AV_OPT_TYPE_CONST, {.i64 = ZIMG_CHROMA_TOP_LEFT},     0, 0, FLAGS, "chroma" },

+    {     "top",       0, 0, AV_OPT_TYPE_CONST, {.i64 = ZIMG_CHROMA_TOP},          0, 0, FLAGS, "chroma" },

+    {     "bottomleft",0, 0, AV_OPT_TYPE_CONST, {.i64 = ZIMG_CHROMA_BOTTOM_LEFT},  0, 0, FLAGS, "chroma" },

+    {     "bottom",    0, 0, AV_OPT_TYPE_CONST, {.i64 = ZIMG_CHROMA_BOTTOM},       0, 0, FLAGS, "chroma" },

+    { "chromalin",  "set input chroma location", OFFSET(chromal_in), AV_OPT_TYPE_INT, {.i64 = -1}, -1, ZIMG_CHROMA_BOTTOM, FLAGS, "chroma" },

+    { "cin",        "set input chroma location", OFFSET(chromal_in), AV_OPT_TYPE_INT, {.i64 = -1}, -1, ZIMG_CHROMA_BOTTOM, FLAGS, "chroma" },

     { NULL }

 };