Patent ID: 8731946
Filing Date: 2014-05-20
Classification: G11B

Abstract:
1. A method for starting, in a decoder apparatus, a decoding of a frame based bit stream format file that represents an hd3/mp3 audio signal, said bit stream including at least one bit stream header section, said frames including encoded hd3/mp3 audio signal data, wherein data required for a decoding of data of a current frame, or an evaluation of data of a current frame, is/are contained in one or more previous frames, and wherein in said header section, information items are arranged representing: total number of samples per channel for said file; an ‘archival mode’ or a ‘streaming mode’ for said file; whether or not a decoding of said encoded audio signal data starts at the first frame of said file wherein, if not true, the decoding of a current frame requires knowledge of decoding states initialization data from one or more frames previous to said current frame; if a decoding of said encoded audio signal data is not to start at said first frame of said file, a number of initial frames to mute while decoding states are initialized, and if there is a sample-exact cutting feature, a number of samples to mute in the corresponding frame; in said streaming mode, a value for identifying a previous super frame for a consistency check, wherein in said archival mode, said file includes a single bit stream header section and successive ones of said frames, and a decoding of said encoded audio signal data is to start with the first one of said frames, and wherein in said streaming mode said bit stream contains more than one super frame, each one of said super frames starting with a single bit stream header section followed by several ones of said frames, and a decoding of said encoded audio signal data is initialized at each one of said super frames, and wherein said information item regarding the number of initial frames to mute signalizes how many ones of initial frames in a current super frame are required for establishing data for initializing states of a decoding of said audio signal data before actually starting decoding of encoded audio signal data from the following frame or frames of said current super frame, such initial frames not being used for decoding the encoded audio signal data contained therein, said method comprising the steps of: when starting decoding of said streaming mode bit stream at said first super frame, the decoding of the encoded audio signal data starts at the first frame of that super frame using default decoder states; when not starting decoding of said streaming mode bit stream at said first super frame, following a decoding initialization or reset, a number ‘muteFrames’ of frames corresponding to said information item regarding the number of initial frames to mute is used for initializing the decoding states, and the decoding of encoded audio signal data starts at frame number muteFrames+1 of the current super frame using these decoding states; when not starting decoding of said streaming mode bit stream at said first super frame, and consistency check data that were calculated from the previous super frame data is not consistent with corresponding consistency check data calculated from the current super frame, using a number ‘muteFrames’ of frames of the following super frame for re-initializing the decoding states starting decoding of encoded audio signal data at frame number ‘muteFrames’+1 of that following super frame using these decoding states; when not starting decoding of said streaming mode bit stream at said first super frame, and a super frame was decoded before and said consistency check data are valid, using the decoder states of the previously decoded super frame to decode the encoded audio signal data of the frames of the current super frame.