oiiodecoder: implemented heuristic to auto-detect start and end index

app/codec/oiio/oiiodecoder.cpp

@@ -86,11 +86,23 @@ bool OIIODecoder::Probe(Footage *f, const QAtomicInt *cancelled)
     video_stream->set_frame_rate(default_timebase.flipped());
     video_stream->set_image_sequence(true);
 
-    // FIXME: Get actual start number
-    video_stream->set_start_time(1);
+    int64_t seq_index = GetImageSequenceIndex(f->filename());
 
-    // FIXME: Get actual duration
-    video_stream->set_duration(200);
+    int64_t start_index = seq_index;
+    int64_t end_index = seq_index;
+
+    // Heuristic to find the first and last images (users can always override this later in FootagePropertiesDialog)
+    while (QFileInfo::exists(TransformImageSequenceFileName(f->filename(), start_index-1))) {
+      start_index--;
+    }
+
+    while (QFileInfo::exists(TransformImageSequenceFileName(f->filename(), end_index+1))) {
+      end_index++;
+    }
+
+    video_stream->set_start_time(start_index);
+
+    video_stream->set_duration(end_index - start_index);
   } else {
     image_stream = std::make_shared<ImageStream>();
   }
@@ -261,6 +273,19 @@ QString OIIODecoder::TransformImageSequenceFileName(const QString &filename, con
   return file_info.dir().filePath(file_info.fileName().replace(original_basename, new_basename));
 }
 
+int64_t OIIODecoder::GetImageSequenceIndex(const QString &filename)
+{
+  int digit_count = GetImageSequenceDigitCount(filename);
+
+  QFileInfo file_info(filename);
+
+  QString original_basename = file_info.baseName();
+
+  QString number_only = original_basename.mid(original_basename.size() - digit_count);
+
+  return number_only.toLongLong();
+}
+
 bool OIIODecoder::OpenImageHandler(const QString &fn)
 {
   image_ = OIIO::ImageInput::open(fn.toStdString());

app/codec/oiio/oiiodecoder.h

@@ -58,6 +58,8 @@ private:
 
   static QString TransformImageSequenceFileName(const QString& filename, const int64_t& number);
 
+  static int64_t GetImageSequenceIndex(const QString& filename);
+
   bool OpenImageHandler(const QString& fn);
 
   void CloseImageHandle();