fftools/ffmpeg: use local variable with same contents directly

Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

fftools/ffmpeg.c

@@ -501,32 +501,37 @@ static void ffmpeg_cleanup(int ret)
         FilterGraph *fg = filtergraphs[i];
         avfilter_graph_free(&fg->graph);
         for (j = 0; j < fg->nb_inputs; j++) {
-            while (av_fifo_size(fg->inputs[j]->frame_queue)) {
+            InputFilter *ifilter = fg->inputs[j];
+            struct InputStream *ist = ifilter->ist;
+
+            while (av_fifo_size(ifilter->frame_queue)) {
                 AVFrame *frame;
-                av_fifo_generic_read(fg->inputs[j]->frame_queue, &frame,
+                av_fifo_generic_read(ifilter->frame_queue, &frame,
                                      sizeof(frame), NULL);
                 av_frame_free(&frame);
             }
-            av_fifo_freep(&fg->inputs[j]->frame_queue);
-            if (fg->inputs[j]->ist->sub2video.sub_queue) {
-                while (av_fifo_size(fg->inputs[j]->ist->sub2video.sub_queue)) {
+            av_fifo_freep(&ifilter->frame_queue);
+            if (ist->sub2video.sub_queue) {
+                while (av_fifo_size(ist->sub2video.sub_queue)) {
                     AVSubtitle sub;
-                    av_fifo_generic_read(fg->inputs[j]->ist->sub2video.sub_queue,
+                    av_fifo_generic_read(ist->sub2video.sub_queue,
                                          &sub, sizeof(sub), NULL);
                     avsubtitle_free(&sub);
                 }
-                av_fifo_freep(&fg->inputs[j]->ist->sub2video.sub_queue);
+                av_fifo_freep(&ist->sub2video.sub_queue);
             }
-            av_buffer_unref(&fg->inputs[j]->hw_frames_ctx);
-            av_freep(&fg->inputs[j]->name);
+            av_buffer_unref(&ifilter->hw_frames_ctx);
+            av_freep(&ifilter->name);
             av_freep(&fg->inputs[j]);
         }
         av_freep(&fg->inputs);
         for (j = 0; j < fg->nb_outputs; j++) {
-            av_freep(&fg->outputs[j]->name);
-            av_freep(&fg->outputs[j]->formats);
-            av_freep(&fg->outputs[j]->channel_layouts);
-            av_freep(&fg->outputs[j]->sample_rates);
+            OutputFilter *ofilter = fg->outputs[j];
+
+            av_freep(&ofilter->name);
+            av_freep(&ofilter->formats);
+            av_freep(&ofilter->channel_layouts);
+            av_freep(&ofilter->sample_rates);
             av_freep(&fg->outputs[j]);
         }
         av_freep(&fg->outputs);