public String getSourceFile() {
        return this.sourceFile;
    }
External caption file used for loading captions. Accepted file extensions are 'scc', 'ttml', 'dfxp', 'stl',
'srt', 'xml', 'smi', 'webvtt', and 'vtt'.

@return External caption file used for loading captions. Accepted file extensions are 'scc', 'ttml', 'dfxp',
        'stl', 'srt', 'xml', 'smi', 'webvtt', and 'vtt'.
aws-java-sdk-mediaconvert/src/main/java/com/amazonaws/services/mediaconvert/model/FileSourceSettings.java