[FFmpeg-devel] [PATCH 2/4] avfilter/avfilter: add AVFilterGraph->max_buffered_frames to limit buffered frames

[Marton Balint]

Signed-off-by: Marton Balint <cus at passwd.hu>
---
 doc/APIchanges              | 3 +++
 libavfilter/avfilter.h      | 8 ++++++++
 libavfilter/avfiltergraph.c | 4 ++++
 libavfilter/version.h       | 2 +-
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/doc/APIchanges b/doc/APIchanges
index 9c03e541fd..797879f769 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -2,6 +2,9 @@ The last version increases of all libraries were on 2025-03-28
 
 API changes, most recent first:
 
+2025-07-xx - xxxxxxxxxd - lavfi 11.2.100 - avfilter.h
+  Add AVFilterGraph->max_buffered_frames.
+
 2025-07-01 - 39d5a998bd - lavc 62.4.101 - packet.h
   Add AV_PKT_DATA_3D_REFERENCE_DISPLAYS.
 
diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index f85929dc5c..d2571b1404 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -629,6 +629,14 @@ typedef struct AVFilterGraph {
     avfilter_execute_func *execute;
 
     char *aresample_swr_opts; ///< swr options to use for the auto-inserted aresample filters, Access ONLY through AVOptions
+
+    /**
+     * Sets the maximum number of buffered frames in the filtergraph combined.
+     *
+     * Zero means no limit. This field must be set before calling
+     * avfilter_graph_config().
+     */
+    unsigned max_buffered_frames;
 } AVFilterGraph;
 
 /**
diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index 38b89db22a..86da0b9975 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -56,6 +56,8 @@ static const AVOption filtergraph_options[] = {
         AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, F|V },
     {"aresample_swr_opts"   , "default aresample filter options"    , OFFSET(aresample_swr_opts)    ,
         AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, F|A },
+    {"max_buffered_frames"  , "maximum number of buffered frames allowed", OFFSET(max_buffered_frames),
+        AV_OPT_TYPE_UINT,   {.i64 = 0}, 0, UINT_MAX, F|V|A },
     { NULL },
 };
 
@@ -1296,6 +1298,8 @@ int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx)
 {
     int ret;
 
+    if (graphctx->max_buffered_frames)
+        fffiltergraph(graphctx)->frame_queues.max_queued = graphctx->max_buffered_frames;
     if ((ret = graph_check_validity(graphctx, log_ctx)))
         return ret;
     if ((ret = graph_config_formats(graphctx, log_ctx)))
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 1e884d9b44..bece922c7f 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -31,7 +31,7 @@
 
 #include "version_major.h"
 
-#define LIBAVFILTER_VERSION_MINOR   1
+#define LIBAVFILTER_VERSION_MINOR   2
 #define LIBAVFILTER_VERSION_MICRO 100
 
 
-- 
2.43.0