Change avfilter_open() signature, from:

AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
to:
int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);

This way it is possible to propagate an error code telling the reason
of the failure.

Originally committed as revision 24765 to svn://svn.ffmpeg.org/ffmpeg/trunk

4 files changed, 13 insertions, 9 deletions

diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
index b4e1c20023..e31aeac3d8 100644
--- a/libavfilter/avfilter.c
+++ b/libavfilter/avfilter.c
@@ -394,12 +394,13 @@ static const AVClass avfilter_class = {
     LIBAVUTIL_VERSION_INT,
 };
 
-AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name)
+int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name)
 {
     AVFilterContext *ret;
+    *filter_ctx = NULL;
 
     if (!filter)
-        return 0;
+        return AVERROR(EINVAL);
 
     ret = av_mallocz(sizeof(AVFilterContext));
 
@@ -422,7 +423,8 @@ AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name)
         ret->outputs      = av_mallocz(sizeof(AVFilterLink*) * ret->output_count);
     }
 
-    return ret;
+    *filter_ctx = ret;
+    return 0;
 }
 
 void avfilter_destroy(AVFilterContext *filter)
diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index da964264d0..0045215ee3 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -25,7 +25,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  1
-#define LIBAVFILTER_VERSION_MINOR 32
+#define LIBAVFILTER_VERSION_MINOR 33
 #define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
@@ -660,11 +660,14 @@ AVFilter **av_filter_next(AVFilter **filter);
 
 /**
  * Create a filter instance.
+ *
+ * @param filter_ctx put here a pointer to the created filter context
+ * on success, NULL on failure
  * @param filter    the filter to create an instance of
  * @param inst_name Name to give to the new instance. Can be NULL for none.
- * @return          Pointer to the new instance on success. NULL on failure.
+ * @return >= 0 in case of success, a negative error code otherwise
  */
-AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
+int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
 
 /**
  * Initialize a filter.
diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index 6f219a62b5..2123c2806c 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -133,8 +133,7 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
                     /* couldn't merge format lists. auto-insert scale filter */
                     snprintf(inst_name, sizeof(inst_name), "auto-inserted scaler %d",
                              scaler_count++);
-                    scale =
-                        avfilter_open(avfilter_get_by_name("scale"),inst_name);
+                    avfilter_open(&scale, avfilter_get_by_name("scale"), inst_name);
 
                     snprintf(scale_args, sizeof(scale_args), "0:0:%s", graph->scale_sws_opts);
                     if(!scale || scale->filter->init(scale, scale_args, NULL) ||
diff --git a/libavfilter/graphparser.c b/libavfilter/graphparser.c
index 5b3f89ef53..c4f621b87e 100644
--- a/libavfilter/graphparser.c
+++ b/libavfilter/graphparser.c
@@ -111,7 +111,7 @@ static AVFilterContext *create_filter(AVFilterGraph *ctx, int index,
         return NULL;
     }
 
-    filt_ctx = avfilter_open(filt, inst_name);
+    avfilter_open(&filt_ctx, filt, inst_name);
     if (!filt_ctx) {
         av_log(log_ctx, AV_LOG_ERROR,
                "Error creating filter '%s'\n", filt_name);