Patent ID: 7924916
Filing Date: 2011-04-12
Classification: H04N

Abstract:
1. Method for decoding encoded groups of pictures denoted GOP of a video sequence and presenting or displaying said video sequence and said GOPs in temporally backward direction, wherein each GOP includes anchor pictures serving for prediction of other pictures and interspersed non-anchor pictures not serving for prediction of other pictures, and wherein decoding of a current one of said GOPs starts with decoding anchor pictures of said current GOP from its beginning but the presentation or display of all the pictures of said current GOP starts with presenting or displaying the pictures of said current GOP from its end and continues until its beginning, whereby the non-anchor pictures are decoded from a bit buffer on-the-fly using the corresponding adjacent ones of said stored decoded anchor pictures, said method including the steps: initially storing only a group of last decoded anchor pictures of the first GOP in dedicated picture buffers and starting presentation or display of said current GOP using said initially stored decoded anchor pictures and the corresponding interspersed non-anchor pictures, wherein the total number of such dedicated picture buffers is less than the total number of anchor pictures per GOP, and wherein a specific one of said decoded anchor pictures of said current GOP is intermediately stored in a dedicated picture buffer that is not overwritten by any other decoded anchor picture of said current GOP, said specific anchor picture being located at a position in GOP display time that is one half or about one half of the time period between the start of the current GOP and said group of last decoded anchor pictures, and said specific decoded anchor picture is used at least once per GOP for re-start of decoding of anchor pictures of the GOP from that position instead of from the very beginning of the GOP; continuing, until arrival at the beginning of said current GOP, the presentation or display of the remaining pictures of said current GOP using remaining ones of decoded anchor pictures intermediately stored in said dedicated picture buffers and using the corresponding interspersed non-anchor pictures, thereby repeating at least once the presentation or display of at least two of said decoded anchor pictures of said current GOP, in order to make available decoding processing time for repeatedly decoding those anchor pictures of said current GOP which do not belong to said group of last decoded anchor pictures of said current group of picture, and wherein said presentation or display of a current GOP is carried out such that when finalizing it the corresponding decoded anchor pictures for the following GOP to be presented or displayed are again stored in said dedicated picture buffers.