[FFmpeg-devel] [PATCH v2 2/8] avfilter/vf_setparams: allow setting chroma location

[Niklas Haas]

From: Niklas Haas <git at haasn.dev>

Shockingly, there isn't currently _any_ filter for overriding this.
---
 doc/filters.texi           | 17 +++++++++++++++++
 libavfilter/vf_setparams.c | 19 ++++++++++++++++---
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index c9c4f7cf6b..ca8f6e461a 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -22073,6 +22073,23 @@ Keep the same colorspace property (default).
 @item chroma-derived-c
 @item ictcp
 @end table
+
+ at item chroma_location
+Set the chroma sample location.
+Available values are:
+
+ at table @samp
+ at item auto
+Keep the same chroma location (default).
+
+ at item unspecified, unknown
+ at item left
+ at item center
+ at item topleft
+ at item top
+ at item bottomleft
+ at item bottom
+ at end table
 @end table
 
 @section sharpen_npp
diff --git a/libavfilter/vf_setparams.c b/libavfilter/vf_setparams.c
index b7da8eb54b..ba32a6699c 100644
--- a/libavfilter/vf_setparams.c
+++ b/libavfilter/vf_setparams.c
@@ -41,6 +41,7 @@ typedef struct SetParamsContext {
     int color_primaries;
     int color_trc;
     int colorspace;
+    int chroma_location;
 } SetParamsContext;
 
 #define OFFSET(x) offsetof(SetParamsContext, x)
@@ -119,6 +120,17 @@ static const AVOption setparams_options[] = {
     {"chroma-derived-c",           NULL,  0, AV_OPT_TYPE_CONST, {.i64=AVCOL_SPC_CHROMA_DERIVED_CL}, INT_MIN, INT_MAX, FLAGS, .unit = "colorspace"},
     {"ictcp",                      NULL,  0, AV_OPT_TYPE_CONST, {.i64=AVCOL_SPC_ICTCP},             INT_MIN, INT_MAX, FLAGS, .unit = "colorspace"},
     {"ipt-c2",                     NULL,  0, AV_OPT_TYPE_CONST, {.i64=AVCOL_SPC_IPT_C2},            INT_MIN, INT_MAX, FLAGS, .unit = "colorspace"},
+
+    {"chroma_location", "select chroma sample location", OFFSET(chroma_location), AV_OPT_TYPE_INT, {.i64=-1}, -1, AVCHROMA_LOC_NB-1, FLAGS, .unit = "chroma_location"},
+    {"auto", "keep the same chroma location",  0, AV_OPT_TYPE_CONST, {.i64=-1},                       INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
+    {"unspecified",                      NULL, 0, AV_OPT_TYPE_CONST, {.i64=AVCHROMA_LOC_UNSPECIFIED}, INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
+    {"unknown",                          NULL, 0, AV_OPT_TYPE_CONST, {.i64=AVCHROMA_LOC_UNSPECIFIED}, INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
+    {"left",                             NULL, 0, AV_OPT_TYPE_CONST, {.i64=AVCHROMA_LOC_LEFT},        INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
+    {"center",                           NULL, 0, AV_OPT_TYPE_CONST, {.i64=AVCHROMA_LOC_CENTER},      INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
+    {"topleft",                          NULL, 0, AV_OPT_TYPE_CONST, {.i64=AVCHROMA_LOC_TOPLEFT},     INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
+    {"top",                              NULL, 0, AV_OPT_TYPE_CONST, {.i64=AVCHROMA_LOC_TOP},         INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
+    {"bottomleft",                       NULL, 0, AV_OPT_TYPE_CONST, {.i64=AVCHROMA_LOC_BOTTOMLEFT},  INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
+    {"bottom",                           NULL, 0, AV_OPT_TYPE_CONST, {.i64=AVCHROMA_LOC_BOTTOM},      INT_MIN, INT_MAX, FLAGS, .unit = "chroma_location"},
     {NULL}
 };
 
@@ -174,17 +186,18 @@ FF_ENABLE_DEPRECATION_WARNINGS
             frame->flags &= ~AV_FRAME_FLAG_TOP_FIELD_FIRST;
     }
 
-    /* set range */
+    /* set straightforward parameters */
     if (s->color_range >= 0)
         frame->color_range = s->color_range;
-
-    /* set color prim, trc, space */
     if (s->color_primaries >= 0)
         frame->color_primaries = s->color_primaries;
     if (s->color_trc >= 0)
         frame->color_trc = s->color_trc;
     if (s->colorspace >= 0)
         frame->colorspace = s->colorspace;
+    if (s->chroma_location >= 0)
+        frame->chroma_location = s->chroma_location;
+
     return ff_filter_frame(ctx->outputs[0], frame);
 }
 
-- 
2.45.2