The present document relates to methods and systems for encoding and decoding multimedia files. In particular, the present document relates to methods and systems for encoding and decoding a plurality of audio tracks for seamless playback of the plurality of audio tracks. A method for encoding an audio signal comprising a first and a directly following second audio track for seamless and individual playback of the first and second audio tracks is described. The first and second audio tracks comprise a first and second plurality of audio frames, respectively. The method comprises jointly encoding the audio signal using a frame based audio encoder, thereby yielding a continuous sequence of encoded frames; extracting a first plurality of encoded frames from the continuous sequence of encoded frames; extracting a second plurality of encoded frames from the continuous sequence of encoded frames; appending one or more rear extension frames to an end of the first plurality of encoded frames; and appending one or more front extension frames to the beginning of the second plurality of encoded frames.