Generation of MPEG slow motion playout
First Claim
1. A method of slowing an MPEG coded video stream, the MPEG coded video stream including groups of pictures (GOPs), each group of pictures including one or more I-frames and a plurality of B- or P-frames, said method comprising:
- a) identifying coding type of each frame in the MPEG-coded video stream; and
b) inserting freeze frames as a predefined function of the identified coding type and as a predefined function of a desired slow down factor.
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Accused Products
Abstract
MPEG coded video data includes groups of pictures (GOPs). Each group of pictures includes one or more I-frames and a plurality of B- or P-frames. To produce an MPEG slow-forward coded video stream, the coding type of each frame in the MPEG coded video data is identified, and freeze frames are inserted as a predefined function of the identified coding type and as a predefined function of a desired slow down factor. In a preferred implementation, for a slow-down factor of n, for each original I- or P-frame, (n−1) backward-predicted freeze frames are inserted, and for each original B-frame, (n−1) copies of the original B-frames are added, and a selected amount of padding is added to each copy of each original B-frame in order to obtain a normal play bit rate and avoid video buffer overflow or underflow.
31 Citations
20 Claims
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1. A method of slowing an MPEG coded video stream, the MPEG coded video stream including groups of pictures (GOPs), each group of pictures including one or more I-frames and a plurality of B- or P-frames, said method comprising:
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a) identifying coding type of each frame in the MPEG-coded video stream; and
b) inserting freeze frames as a predefined function of the identified coding type and as a predefined function of a desired slow down factor. - View Dependent Claims (2, 3, 4, 5)
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6. A method of producing an MPEG slow-forward coded video stream from MPEG coded video data, the MPEG coded video data including groups of pictures (GOPs), the groups of pictures including I-frames, P-frames, and B-frames, said method comprising:
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for each frame in the MPEG coded video data, identifying coding type of said each frame, and for said each frame identified as an I-frame or P-frame, adding at least one predicted freeze frame to said each frame identified as an I-frame or P-frame to produce frames included in the MPEG slow-forward coded video stream, the predicted freeze frame being dependent on said each frame identified as an I-frame or P-frame; and
for said each frame identified as a B-frame, adding at least one copy of said each frame identified as a B-frame to said each frame identified as a B-frame to produce frames included in the MPEG slow-forward coded video stream. - View Dependent Claims (7, 8, 9, 10)
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11. An apparatus for producing an MPEG slow-forward coded video stream from MPEG coded video data, the MPEG coded video data including groups of pictures (GOPs), each group of pictures including one or more I-frames and a plurality of B- or P-frames, said apparatus comprising:
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storage for containing the MPEG coded video data; and
a processor coupled to the storage for receiving a stream of the MPEG coded video data from the storage, the processor being programmed for identifying coding type of each frame in the stream of MPEG-coded video data from the storage, and inserting freeze frames as a predefined function of the identified coding type and as a predefined function of a desired slow down factor. - View Dependent Claims (12, 13, 14, 15)
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16. An apparatus for producing an MPEG slow-forward coded video stream from MPEG coded video data, the MPEG coded video data including groups of pictures (GOPs), the groups of pictures including I-frames, P-frames, and B-frames, said apparatus comprising:
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storage for containing the MPEG coded video data; and
a processor coupled to the storage for receiving a stream of the MPEG coded video data from the storage, the processor being programmed for identifying coding type of each frame in the stream of the MPEG coded video data from the storage, and for said each frame identified as an I-frame or P-frame, adding at least one predicted freeze frame to said each frame identified as an I-frame or P-frame to produce frames included in the MPEG slow-forward coded video stream, the predicted freeze frame being dependent on said each frame identified as an I-frame or P-frame; and
for said each frame identified as a B-frame, adding at least one copy of said each frame identified as a B-frame to said each frame identified as a B-frame to produce frames included in the MPEG slow-forward coded video stream. - View Dependent Claims (17, 18, 19, 20)
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Specification