[FFmpeg-devel] [PATCH] lavf/fps: add cmd to force write buf frame

[Jai Luthra]

Enables writing buffered frames to the outsink using send command api.

This is useful when a lavf user wants to fetch buffered frames without
closing/reopening the filtergraph again and again.

Signed-off-by: Jai Luthra <me at jailuthra.in>
---
 libavfilter/vf_fps.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/libavfilter/vf_fps.c b/libavfilter/vf_fps.c
index cf1e36726a..fa856a8f45 100644
--- a/libavfilter/vf_fps.c
+++ b/libavfilter/vf_fps.c
@@ -326,6 +326,23 @@ static int activate(AVFilterContext *ctx)
     return FFERROR_NOT_READY;
 }
 
+static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
+                           char *res, int res_len, int flags)
+{
+    FPSContext *s = ctx->priv;
+    int ret, again = 0;
+
+    if (!strcmp(cmd, "force_write")) {
+        AVFilterLink *outlink = ctx->outputs[0];
+        ret = write_frame(ctx, s, outlink, &again);
+        if (again)
+            ff_filter_set_ready(ctx, 100);
+    } else
+        ret = AVERROR(ENOSYS);
+
+    return ret;
+}
+
 static const AVFilterPad avfilter_vf_fps_inputs[] = {
     {
         .name         = "default",
@@ -344,13 +361,14 @@ static const AVFilterPad avfilter_vf_fps_outputs[] = {
 };
 
 AVFilter ff_vf_fps = {
-    .name        = "fps",
-    .description = NULL_IF_CONFIG_SMALL("Force constant framerate."),
-    .init        = init,
-    .uninit      = uninit,
-    .priv_size   = sizeof(FPSContext),
-    .priv_class  = &fps_class,
-    .activate    = activate,
-    .inputs      = avfilter_vf_fps_inputs,
-    .outputs     = avfilter_vf_fps_outputs,
+    .name            = "fps",
+    .description     = NULL_IF_CONFIG_SMALL("Force constant framerate."),
+    .init            = init,
+    .uninit          = uninit,
+    .priv_size       = sizeof(FPSContext),
+    .priv_class      = &fps_class,
+    .activate        = activate,
+    .inputs          = avfilter_vf_fps_inputs,
+    .outputs         = avfilter_vf_fps_outputs,
+    .process_command = process_command,
 };
-- 
2.26.2