Processing of MPEG encoded video for trick mode operation

A method of processing original-quality MPEG coded video to produce reduced-quality MPEG coded video for trick mode operation, the MPEG coded video including a set of non-zero AC discrete cosine transform (DCT) coefficients for 8×8 blocks in I-frames of the MPEG coded video, said method including the steps of removing non-zero AC DCT coefficients from the 8×8 blocks of I-frames of the MPEG coded video to produce I-frames of reduced-quality MPEG coded video, and inserting freeze frames in the reduced-quality MPEG coded video,

• wherein the original-quality MPEG coded video is included in an original-quality MPEG transport stream, and the method includes producing an MPEG trick-mode transport stream including the reduced-quality MPEG coded video and the freeze frames inserted into the reduced-quality MPEG coded video,
• which further includes extracting from the original-quality MPEG transport stream an audio presentation unit (APU) for each I frame in the reduced-quality MPEG coded video, the audio presentation unit having, in the original-quality MPEG transport stream, an audio presentation time that first begins in a video presentation time of a corresponding I frame in the original-quality MPEG transport stream, and inserting the audio presentation unit into the reduced-quality MPEG transport stream so that, in the reduced-quality MPEG transport stream, the audio presentation unit has an audio presentation time that first begins in a video presentation time of said each I frame.

A data storage device containing a main file, a fast-forward file and a fast-reverse file, the main file containing data of an MPEG transport stream including groups of pictures (GOPs), each GOP including an original-quality I-frame and a plurality of P or B-frames, the fast-forward file containing data of a fast-forward MPEG transport stream including GOPs, each GOP in the fast-forward file corresponding to a GOP in the main file and including at least one reduced-quality I frame corresponding to the original-quality I frame in the corresponding GOP of the main file, the fast-reverse file containing data of a fast-reverse MPEG transport stream including GOPs, each GOP in the fast-reverse file corresponding to a GOP in the main file and including at least one reduced/quality I-frame corresponding to the original-quality I frame in the corresponding GOP of the main file, wherein a reading of the main file produces an MPEG transport stream for an audio-visual presentation at a normal rate, a reading of the fast-forward file produces an MPEG transport stream of the audio-visual presentation in a forward direction at a fast rate, and a reading of the fast-reverse file produces an MPEG transport stream of the audio-visual presentation in a reverse direction at a fast rate,

• wherein the fast-forward file and the fast-reverse file share a volume with the main file, and the volume includes an index linking the GOPs of the fast-forward file and the fast-reverse file to corresponding GOPs of the main file.

A file server including at least one data storage device, the data storage device containing a main file, a fast-forward file and a fast-reverse file, the main file containing data of an MPEG transport stream including groups of pictures (GOPs), each GOP including an original-quality I-frame and a plurality of P or B-frames, the fast-forward file containing data of a fast-forward MPEG transport stream including GOPs, each GOP in the fast-forward file corresponding to a GOP in the main file and including at least one reduced-quality I frame corresponding to the original-quality I frame in the corresponding GOP of the main file, the fast-reverse file containing data of a fast-reverse MPEG transport stream including GOPs, each GOP in the fast-reverse file corresponding to a GOP in the main file and including at least one reduced-quality I-frame corresponding to the original-quality I frame in the corresponding GOP of the main file,

• wherein the file server is programmed to respond to a client request for an audio-visual presentation at a normal rate by reading the main file and streaming MPEG data from the main file to the client,
• wherein the file server is programmed to respond to a client request for the audio-visual presentation in a forward direction at a fast rate by reading the fast-forward file and streaming MPEG data from the fast-forward file to the client,
• wherein the file server is programmed to respond to a client request for the audio-visual presentation in a reverse order at a fast rate by reading the fast-reverse file and streaming MPEG data from the fast-reverse file to the client,
• wherein the file server is programmed to allocate a volume for the main file, the fast-forward file, and the fast-reverse file when the main file is ingested into the file server, and
• wherein the volume further includes an index linking the GOPs of the fast-forward file and the fast-reverse file to corresponding GOPs of the main file.