A decoding apparatus and method for producing a browsable slide show and a data storage medium therefor. The decoding apparatus having a mainstream decoder, which decodes mainstream packet data including image data to be reproduced in a browsable slide show; a sub-audio decoder, which decodes sub-audio packet data including audio data attached to the image data; a mainstream system time clock (STC) counter, which provides an STC sequence for controlling the decoding time of the mainstream packet data to the mainstream decoder; and a sub-audio STC counter, which provides an STC sequence for controlling the decoding time of the sub-audio packet data to the sub-audio decoder. Accordingly, it is possible to seamlessly reproduce sub-audio data even when a user selects a forward or reverse play in the middle of reproducing still image data with the sub-audio data attached thereto in a browsable slide show.