more or less completed OIIO decoder

app/decoder/decoder.cpp

@@ -62,6 +62,9 @@ void Decoder::set_stream(StreamPtr fs)
 QVector<DecoderPtr> ReceiveListOfAllDecoders() {
   QVector<DecoderPtr> decoders;
 
+  // The order in which these decoders are added is their priority when probing. Hence FFmpeg should usually be last,
+  // since it supports so many formats and we presumably want to override those formats with a more specific decoder.
+
   decoders.append(std::make_shared<OIIODecoder>());
   decoders.append(std::make_shared<FFmpegDecoder>());