fftools/ffmpeg: move closing the input file into a separate function

For now this is just closing the format context and freeing InputFile,
but will contain more in the future.

fftools/ffmpeg.c

@@ -556,10 +556,9 @@ static void ffmpeg_cleanup(int ret)
         of_close(&output_files[i]);
 
     free_input_threads();
-    for (i = 0; i < nb_input_files; i++) {
+    for (i = 0; i < nb_input_files; i++)
-        avformat_close_input(&input_files[i]->ctx);
+        ifile_close(&input_files[i]);
-        av_freep(&input_files[i]);
+
-    }
     for (i = 0; i < nb_input_streams; i++) {
         InputStream *ist = input_streams[i];
 

fftools/ffmpeg.h

@@ -758,6 +758,7 @@ AVChapter * const *
 of_get_chapters(OutputFile *of, unsigned int *nb_chapters);
 
 int ifile_open(OptionsContext *o, const char *filename);
+void ifile_close(InputFile **f);
 
 /**
  * Get next input packet from the demuxer.

fftools/ffmpeg_demux.c

@@ -439,6 +439,18 @@ int ifile_get_packet(InputFile *f, AVPacket **pkt)
     return 0;
 }
 
+void ifile_close(InputFile **pf)
+{
+    InputFile *f = *pf;
+
+    if (!f)
+        return;
+
+    avformat_close_input(&f->ctx);
+
+    av_freep(pf);
+}
+
 static const AVCodec *choose_decoder(OptionsContext *o, AVFormatContext *s, AVStream *st,
                                      enum HWAccelID hwaccel_id, enum AVHWDeviceType hwaccel_device_type)