avconv: split creating and (re-)configuring complex filtergraphs

The current code is less than straightforward due to the fact that
output streams can be created based on filtergraph definitions. This
change should make the code simpler and more readable. It will also be
useful in the future commits.

avconv.c

@@ -1679,11 +1679,6 @@ static int transcode_init(void)
                 input_streams[j + ifile->ist_index]->start = av_gettime_relative();
     }
 
-    /* init complex filtergraphs */
-    for (i = 0; i < nb_filtergraphs; i++)
-        if ((ret = avfilter_graph_config(filtergraphs[i]->graph, NULL)) < 0)
-            return ret;
-
     /* for each output stream, we compute the right encoding parameters */
     for (i = 0; i < nb_output_streams; i++) {
         AVCodecContext *enc_ctx;

avconv.h

@@ -202,6 +202,7 @@ typedef struct OutputFilter {
 
     /* temporary storage until stream maps are processed */
     AVFilterInOut       *out_tmp;
+    enum AVMediaType     type;
 } OutputFilter;
 
 typedef struct FilterGraph {
@@ -424,6 +425,7 @@ int configure_filtergraph(FilterGraph *fg);
 int configure_output_filter(FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out);
 int ist_in_filtergraph(FilterGraph *fg, InputStream *ist);
 FilterGraph *init_simple_filtergraph(InputStream *ist, OutputStream *ost);
+int init_complex_filtergraph(FilterGraph *fg);
 
 int avconv_parse_options(int argc, char **argv);
 

avconv_filter.c

@@ -176,6 +176,45 @@ static void init_input_filter(FilterGraph *fg, AVFilterInOut *in)
     ist->filters[ist->nb_filters - 1] = fg->inputs[fg->nb_inputs - 1];
 }
 
+int init_complex_filtergraph(FilterGraph *fg)
+{
+    AVFilterInOut *inputs, *outputs, *cur;
+    AVFilterGraph *graph;
+    int ret = 0;
+
+    /* this graph is only used for determining the kinds of inputs
+     * and outputs we have, and is discarded on exit from this function */
+    graph = avfilter_graph_alloc();
+    if (!graph)
+        return AVERROR(ENOMEM);
+
+    ret = avfilter_graph_parse2(graph, fg->graph_desc, &inputs, &outputs);
+    if (ret < 0)
+        goto fail;
+
+    for (cur = inputs; cur; cur = cur->next)
+        init_input_filter(fg, cur);
+
+    for (cur = outputs; cur;) {
+        GROW_ARRAY(fg->outputs, fg->nb_outputs);
+        fg->outputs[fg->nb_outputs - 1] = av_mallocz(sizeof(*fg->outputs[0]));
+        if (!fg->outputs[fg->nb_outputs - 1])
+            exit(1);
+
+        fg->outputs[fg->nb_outputs - 1]->graph   = fg;
+        fg->outputs[fg->nb_outputs - 1]->out_tmp = cur;
+        fg->outputs[fg->nb_outputs - 1]->type    = avfilter_pad_get_type(cur->filter_ctx->output_pads,
+                                                                         cur->pad_idx);
+        cur = cur->next;
+        fg->outputs[fg->nb_outputs - 1]->out_tmp->next = NULL;
+    }
+
+fail:
+    avfilter_inout_free(&inputs);
+    avfilter_graph_free(&graph);
+    return ret;
+}
+
 static int insert_trim(int64_t start_time, int64_t duration,
                        AVFilterContext **last_filter, int *pad_idx,
                        const char *filter_name)
@@ -622,7 +661,7 @@ static int configure_input_filter(FilterGraph *fg, InputFilter *ifilter,
 int configure_filtergraph(FilterGraph *fg)
 {
     AVFilterInOut *inputs, *outputs, *cur;
-    int ret, i, init = !fg->graph, simple = !fg->graph_desc;
+    int ret, i, simple = !fg->graph_desc;
     const char *graph_desc = simple ? fg->outputs[0]->ost->avfilter :
                                       fg->graph_desc;
 
@@ -657,35 +696,17 @@ int configure_filtergraph(FilterGraph *fg)
         return AVERROR(EINVAL);
     }
 
-    for (cur = inputs; !simple && init && cur; cur = cur->next)
-        init_input_filter(fg, cur);
-
     for (cur = inputs, i = 0; cur; cur = cur->next, i++)
         if ((ret = configure_input_filter(fg, fg->inputs[i], cur)) < 0)
             return ret;
     avfilter_inout_free(&inputs);
 
-    if (!init || simple) {
-        /* we already know the mappings between lavfi outputs and output streams,
-         * so we can finish the setup */
-        for (cur = outputs, i = 0; cur; cur = cur->next, i++)
-            configure_output_filter(fg, fg->outputs[i], cur);
-        avfilter_inout_free(&outputs);
+    for (cur = outputs, i = 0; cur; cur = cur->next, i++)
+        configure_output_filter(fg, fg->outputs[i], cur);
+    avfilter_inout_free(&outputs);
 
-        if ((ret = avfilter_graph_config(fg->graph, NULL)) < 0)
-            return ret;
-    } else {
-        /* wait until output mappings are processed */
-        for (cur = outputs; cur;) {
-            GROW_ARRAY(fg->outputs, fg->nb_outputs);
-            if (!(fg->outputs[fg->nb_outputs - 1] = av_mallocz(sizeof(*fg->outputs[0]))))
-                exit(1);
-            fg->outputs[fg->nb_outputs - 1]->graph   = fg;
-            fg->outputs[fg->nb_outputs - 1]->out_tmp = cur;
-            cur = cur->next;
-            fg->outputs[fg->nb_outputs - 1]->out_tmp->next = NULL;
-        }
-    }
+    if ((ret = avfilter_graph_config(fg->graph, NULL)) < 0)
+        return ret;
 
     return 0;
 }

avconv_opt.c

@@ -1367,8 +1367,7 @@ static void init_output_filter(OutputFilter *ofilter, OptionsContext *o,
 {
     OutputStream *ost;
 
-    switch (avfilter_pad_get_type(ofilter->out_tmp->filter_ctx->output_pads,
-                                  ofilter->out_tmp->pad_idx)) {
+    switch (ofilter->type) {
     case AVMEDIA_TYPE_VIDEO: ost = new_video_stream(o, oc); break;
     case AVMEDIA_TYPE_AUDIO: ost = new_audio_stream(o, oc); break;
     default:
@@ -1389,13 +1388,21 @@ static void init_output_filter(OutputFilter *ofilter, OptionsContext *o,
         exit_program(1);
     }
 
-    if (configure_output_filter(ofilter->graph, ofilter, ofilter->out_tmp) < 0) {
-        av_log(NULL, AV_LOG_FATAL, "Error configuring filter.\n");
-        exit_program(1);
-    }
     avfilter_inout_free(&ofilter->out_tmp);
 }
 
+static int init_complex_filters(void)
+{
+    int i, ret = 0;
+
+    for (i = 0; i < nb_filtergraphs; i++) {
+        ret = init_complex_filtergraph(filtergraphs[i]);
+        if (ret < 0)
+            return ret;
+    }
+    return 0;
+}
+
 static int configure_complex_filters(void)
 {
     int i, ret = 0;
@@ -1471,8 +1478,7 @@ static int open_output_file(OptionsContext *o, const char *filename)
             if (!ofilter->out_tmp || ofilter->out_tmp->name)
                 continue;
 
-            switch (avfilter_pad_get_type(ofilter->out_tmp->filter_ctx->output_pads,
-                                          ofilter->out_tmp->pad_idx)) {
+            switch (ofilter->type) {
             case AVMEDIA_TYPE_VIDEO:    o->video_disable    = 1; break;
             case AVMEDIA_TYPE_AUDIO:    o->audio_disable    = 1; break;
             case AVMEDIA_TYPE_SUBTITLE: o->subtitle_disable = 1; break;
@@ -2228,9 +2234,9 @@ int avconv_parse_options(int argc, char **argv)
     }
 
     /* create the complex filtergraphs */
-    ret = configure_complex_filters();
+    ret = init_complex_filters();
     if (ret < 0) {
-        av_log(NULL, AV_LOG_FATAL, "Error configuring filters.\n");
+        av_log(NULL, AV_LOG_FATAL, "Error initializing complex filters.\n");
         goto fail;
     }
 
@@ -2241,6 +2247,13 @@ int avconv_parse_options(int argc, char **argv)
         goto fail;
     }
 
+    /* configure the complex filtergraphs */
+    ret = configure_complex_filters();
+    if (ret < 0) {
+        av_log(NULL, AV_LOG_FATAL, "Error configuring complex filters.\n");
+        goto fail;
+    }
+
 fail:
     uninit_parse_context(&octx);
     if (ret < 0) {