1. That will cause not only the degraded quality but propagate error until an I-frame arrived successfully.
当视讯在播放时，这些错误的封包往往不但会造成失真也会影响到后续的影像持续错误。
2. It is possible, therefore, to have an'except'block end with the'raise'statement to propagate an error upward after taking some action.
这是可能的，因此，有'except'块结束的'raise'言宣扬向上的错误后，采取了一些行动。