buffer unit 1061 and a second audio sub buffer unit 1062 and the subtitle buffer unit 107 of the av decoding device 10 comprises a first subtitle sub buffer unit 1071 and a second subtitle sub buffer unit 1072 though not limited thereto in an embodiment of the present invention the decapsulator unit 101 decapsulates the first section data to output the first video data the first audio data and the first subtitle data the first audio data are stored in the first audio sub buffer unit 1061 and the first subtitle data are stored in the first subtitle sub buffer unit 1071 afterward the audio decoding unit 108 decodes the first audio data of the first audio sub buffer unit 1061 to generate the first audio and the subtitle decoding unit 109 decodes the first subtitle data of the first subtitle sub buffer unit 1071 to generate the first subtitle in the course of the decoding operation carried out by the audio decoding unit 108 and the subtitle decoding unit 109 the decapsulator unit 101 decapsulates the second section data to output a second video data a second audio data and a second subtitle data meanwhile the second audio data are stored in the second audio sub buffer unit 1062 and the second.