lavfi: remove default config_props() callback and refactor avfilter_config_links()

Link properties have to be checked after config_props() is called to
make sure everything is sane, so the default config_props() for output
links was redundant.

Also remove channel_layout check as it is now negotiated.
Signed-off-by: Stefano Sabatini <stefano.sabatini-lala@poste.it>

libavfilter/avfilter.c

@@ -251,24 +251,51 @@ int avfilter_config_links(AVFilterContext *filter)
             if ((ret = avfilter_config_links(link->src)) < 0)
                 return ret;
 
-            if (!(config_link = link->srcpad->config_props))
-                config_link  = avfilter_default_config_output_link;
-            if ((ret = config_link(link)) < 0)
+            if (!(config_link = link->srcpad->config_props)) {
+                if (link->src->input_count != 1) {
+                    av_log(link->src, AV_LOG_ERROR, "Source filters and filters "
+                                                    "with more than one input "
+                                                    "must set config_props() "
+                                                    "callbacks on all outputs\n");
+                    return AVERROR(EINVAL);
+                }
+            } else if ((ret = config_link(link)) < 0)
                 return ret;
 
-            if (link->time_base.num == 0 && link->time_base.den == 0)
-                link->time_base = link->src && link->src->input_count ?
-                    link->src->inputs[0]->time_base : AV_TIME_BASE_Q;
-
-            if (link->sample_aspect_ratio.num == 0 && link->sample_aspect_ratio.den == 0)
-                link->sample_aspect_ratio = link->src->input_count ?
-                    link->src->inputs[0]->sample_aspect_ratio : (AVRational){1,1};
-
-            if (link->sample_rate == 0 && link->src && link->src->input_count)
-                link->sample_rate = link->src->inputs[0]->sample_rate;
-
-            if (link->channel_layout == 0 && link->src && link->src->input_count)
-                link->channel_layout = link->src->inputs[0]->channel_layout;
+            switch (link->type) {
+            case AVMEDIA_TYPE_VIDEO:
+                if (!link->time_base.num && !link->time_base.den)
+                    link->time_base = link->src->input_count ?
+                        link->src->inputs[0]->time_base : AV_TIME_BASE_Q;
+
+                if (!link->sample_aspect_ratio.num && !link->sample_aspect_ratio.den)
+                    link->sample_aspect_ratio = link->src->input_count ?
+                        link->src->inputs[0]->sample_aspect_ratio : (AVRational){1,1};
+
+                if (link->src->input_count) {
+                    if (!link->w)
+                        link->w = link->src->inputs[0]->w;
+                    if (!link->h)
+                        link->h = link->src->inputs[0]->h;
+                } else if (!link->w || !link->h) {
+                    av_log(link->src, AV_LOG_ERROR,
+                           "Video source filters must set their output link's "
+                           "width and height\n");
+                    return AVERROR(EINVAL);
+                }
+                break;
+
+            case AVMEDIA_TYPE_AUDIO:
+                if (link->src->input_count) {
+                    if (!link->sample_rate)
+                        link->sample_rate = link->src->inputs[0]->sample_rate;
+                } else if (!link->sample_rate) {
+                    av_log(link->src, AV_LOG_ERROR,
+                           "Audio source filters must set their output link's "
+                           "sample_rate\n");
+                    return AVERROR(EINVAL);
+                }
+            }
 
             if ((config_link = link->dstpad->config_props))
                 if ((ret = config_link(link)) < 0)

libavfilter/avfilter.h

@@ -464,9 +464,6 @@ void avfilter_default_end_frame(AVFilterLink *link);
 /** default handler for filter_samples() for audio inputs */
 void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
 
-/** default handler for config_props() for audio/video outputs */
-int avfilter_default_config_output_link(AVFilterLink *link);
-
 /** default handler for get_video_buffer() for video inputs */
 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
                                                      int perms, int w, int h);

libavfilter/defaults.c

@@ -174,29 +174,6 @@ void avfilter_default_filter_samples(AVFilterLink *inlink, AVFilterBufferRef *sa
     inlink->cur_buf = NULL;
 }
 
-/**
- * default config_link() implementation for output video links to simplify
- * the implementation of one input one output video filters */
-int avfilter_default_config_output_link(AVFilterLink *link)
-{
-    if (link->src->input_count && link->src->inputs[0]) {
-        if (link->type == AVMEDIA_TYPE_VIDEO) {
-            link->w = link->src->inputs[0]->w;
-            link->h = link->src->inputs[0]->h;
-            link->time_base = link->src->inputs[0]->time_base;
-        } else if (link->type == AVMEDIA_TYPE_AUDIO) {
-            link->channel_layout = link->src->inputs[0]->channel_layout;
-            link->sample_rate    = link->src->inputs[0]->sample_rate;
-        }
-    } else {
-        /* XXX: any non-simple filter which would cause this branch to be taken
-         * really should implement its own config_props() for this link. */
-        return -1;
-    }
-
-    return 0;
-}
-
 static void set_common_formats(AVFilterContext *ctx, AVFilterFormats *fmts,
                                enum AVMediaType type, int offin, int offout)
 {