avfilter/buffersink: add support for chroma locations

Lets the caller read back the negotiated chroma location and constrain the
sink to a list of accepted ones.

Signed-off-by: Kacper Michajłow <kasper93@gmail.com>

doc/APIchanges

@@ -2,8 +2,9 @@ The last version increases of all libraries were on 2026-06-23.
 
 API changes, most recent first:
 
-2026-09-xx - xxxxxxxxxx - lavfi 12.4.102 - avfilter.h buffersrc.h
-  Add AVFilterLink.chroma_location and AVBufferSrcParameters.chroma_location.
+2026-09-xx - xxxxxxxxxx - lavfi 12.5.100 - avfilter.h buffersrc.h buffersink.h
+  Add AVFilterLink.chroma_location, AVBufferSrcParameters.chroma_location and
+  av_buffersink_get_chroma_location().
 
 2026-09-xx - xxxxxxxxxx - lavc 63.16.100 - avcodec.h
   Add AV_CODEC_CONFIG_CHROMA_LOCATION.

libavfilter/buffersink.c

@@ -58,6 +58,9 @@ typedef struct BufferSinkContext {
     int                *alphamodes;
     unsigned         nb_alphamodes;
 
+    int                *chromalocations;
+    unsigned         nb_chromalocations;
+
     /* only used for audio */
     enum AVSampleFormat *sample_formats;
     unsigned          nb_sample_formats;
@@ -169,6 +172,7 @@ static int init_video(AVFilterContext *ctx)
     TERMINATE_ARRAY(colorranges, -1);
     TERMINATE_ARRAY(colorspaces, -1);
     TERMINATE_ARRAY(alphamodes, -1);
+    TERMINATE_ARRAY(chromalocations, -1);
 
     return common_init(ctx);
 }
@@ -248,6 +252,7 @@ MAKE_AVFILTERLINK_ACCESSOR(AVRational       , sample_aspect_ratio)
 MAKE_AVFILTERLINK_ACCESSOR(enum AVColorSpace, colorspace)
 MAKE_AVFILTERLINK_ACCESSOR(enum AVColorRange, color_range)
 MAKE_AVFILTERLINK_ACCESSOR(enum AVAlphaMode , alpha_mode)
+MAKE_AVFILTERLINK_ACCESSOR(enum AVChromaLocation, chroma_location)
 
 MAKE_AVFILTERLINK_ACCESSOR(int              , sample_rate        )
 
@@ -314,6 +319,11 @@ static int vsink_query_formats(const AVFilterContext *ctx,
         if (ret < 0)
             return ret;
     }
+    if (buf->nb_chromalocations) {
+        ret = ff_set_common_chroma_locations_from_list2(ctx, cfg_in, cfg_out, buf->chromalocations);
+        if (ret < 0)
+            return ret;
+    }
     if (buf->nb_alphamodes) {
         ret = ff_set_common_alpha_modes_from_list2(ctx, cfg_in, cfg_out, buf->alphamodes);
         if (ret < 0)
@@ -358,6 +368,8 @@ static const AVOption buffersink_options[] = {
         AV_OPT_TYPE_INT | AV_OPT_TYPE_FLAG_ARRAY, .max = INT_MAX, .flags = FLAGS },
     { "colorranges",    "array of supported color ranges",  OFFSET(colorranges),
         AV_OPT_TYPE_INT | AV_OPT_TYPE_FLAG_ARRAY, .max = INT_MAX, .flags = FLAGS },
+    { "chromalocations", "array of supported chroma locations", OFFSET(chromalocations),
+        AV_OPT_TYPE_INT | AV_OPT_TYPE_FLAG_ARRAY, .max = INT_MAX, .flags = FLAGS },
     { "alphamodes",     "array of supported color ranges",  OFFSET(alphamodes),
         AV_OPT_TYPE_INT | AV_OPT_TYPE_FLAG_ARRAY, .max = INT_MAX, .flags = FLAGS },
 

libavfilter/buffersink.h

@@ -59,6 +59,7 @@
  *  - colorspaces (array of int),
  *  - colorranges (array of int),
  *  - alphamodes (array of int),
+ *  - chromalocations (array of int),
  *  - sample_formats (array of sample formats),
  *  - samplerates (array of int),
  *  - channel_layouts (array of channel layouts)
@@ -117,6 +118,7 @@ AVRational       av_buffersink_get_sample_aspect_ratio (const AVFilterContext *c
 enum AVColorSpace av_buffersink_get_colorspace         (const AVFilterContext *ctx);
 enum AVColorRange av_buffersink_get_color_range        (const AVFilterContext *ctx);
 enum AVAlphaMode  av_buffersink_get_alpha_mode         (const AVFilterContext *ctx);
+enum AVChromaLocation av_buffersink_get_chroma_location(const AVFilterContext *ctx);
 
 int              av_buffersink_get_channels            (const AVFilterContext *ctx);
 int              av_buffersink_get_ch_layout           (const AVFilterContext *ctx,

libavfilter/version.h

@@ -31,8 +31,8 @@
 
 #include "version_major.h"
 
-#define LIBAVFILTER_VERSION_MINOR   4
-#define LIBAVFILTER_VERSION_MICRO 102
+#define LIBAVFILTER_VERSION_MINOR   5
+#define LIBAVFILTER_VERSION_MICRO 100
 
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \