The present invention provides methods for providing a media content performed by a client and by a server, a client for providing a media content, and a server for providing a media content. The method comprises: transmitting a request for the media content to a server based on a Media Presentation Description (MPD) of the media content; and receiving a segment of the media content based on the MPD, from the server. The MPD includes one or more periods, the period includes one or more adaptation sets, the adaptation set includes one or more representations, the representation includes one or more segments, the period is defined based on a period element including a start attribute and a duration attribute, and each of the representations starts from a start time of the period and continues to an ending point of the period. The start time of the period is determined one of below methods: i) when a start attribute exists in a first period element of the first period, a start time of the first period is equal to the start attribute, ii) when a start attribute does not exist in the first period element of the first period, and when a second period element of the second period includes a duration attribute, the start time of the first period is determined by adding the duration attribute of the second period element to a start time of the second period, and iii) when a start attribute does not exist in the first period element of the first period, and when the first period is the first of the one or more periods, the start time of the first period is set to 0. The second period is previous period with respect to the first period.