_download_json ( config_url , display_id , 'Downloading config JSON' , transform_source = lambda s : s [ s . index ( '{' ): s . rindex ( '}' ) + 1 ]) mediafile = config [ 'mediafile' ] video_url = mediafile [ 'src' ] m = re . search ( r '^(?P<url>rtmpe?://[^/]+/(?P<app>[^/]+?))