avfilter/f_loop: warn about unset loop sizes

Signed-off-by: Marton Balint <cus@passwd.hu>

libavfilter/f_loop.c

@@ -55,6 +55,15 @@ typedef struct LoopContext {
 #define VFLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 #define OFFSET(x) offsetof(LoopContext, x)
 
+static void check_size(AVFilterContext *ctx)
+{
+    LoopContext *s = ctx->priv;
+
+    if (!s->size)
+        av_log(ctx, AV_LOG_WARNING, "Number of %s to loop is not set!\n",
+               ctx->input_pads[0].type == AVMEDIA_TYPE_VIDEO ? "frames" : "samples");
+}
+
 #if CONFIG_ALOOP_FILTER
 
 static int aconfig_input(AVFilterLink *inlink)
@@ -67,6 +76,8 @@ static int aconfig_input(AVFilterLink *inlink)
     if (!s->fifo || !s->left)
         return AVERROR(ENOMEM);
 
+    check_size(ctx);
+
     return 0;
 }
 
@@ -250,6 +261,8 @@ static av_cold int init(AVFilterContext *ctx)
     if (!s->frames)
         return AVERROR(ENOMEM);
 
+    check_size(ctx);
+
     return 0;
 }