Patent ID: 8275247

Claim:
A method for normal reverse playback from an X th Group Of Pictures (GOP) of GOPs of a bitstream, the method comprising: decoding all reference pictures in the Xth GOP; decoding a first reference picture in a stream order in an (X−1)th GOP; and sequentially designating each picture from a first picture in a reverse display order in the Xth GOP as an nth picture having a reverse display order number n and when the nth picture having the reverse display order number n is designated as a display picture, performing: if the nth picture having the reverse display order number n is a reference picture or a B picture and an (n+1)th picture having a reverse display order number (n+1) is a B picture, decoding the (n+1)th picture having the reverse display order number (n+1) in the Xth GOP; if the nth picture having the reverse display order number n is the B picture and the (n+1)th picture having the reverse display order number (n+1) is a reference picture, decoding a next reference picture in the stream order among undecoded reference pictures in the (X−1)th GOP; and if the nth picture having the reverse display order number n is a first picture in a forward display order in the Xth GOP, decoding another first reference picture in a stream order in an (X−2)th GOP.