+ // See if we match ^[a-z]:/, which is probably a URL of some sort
+ // (FFmpeg understands various forms of these).
+ for (size_t i = 0; i < filename.size() - 1; ++i) {
+ if (filename[i] == ':' && filename[i + 1] == '/') {
+ return filename;
+ }
+ if (!isalpha(filename[i])) {
+ break;
+ }
+ }
+