Video delivery device, video receiver and key frame delivery method
AssigneeHitachi, Ltd.
InventorsHiroshi Mine, Shinji Kimura, Kaoru Konishi, Tomokazu Ikki, Naohisa Seko
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Abstract
In this video delivery device including: a storage device storing key frame information including a key frame number included in a contents file and offset from the beginning of a file; and a delivery control unit, which executes delivery in a predetermined cycle, the delivery control unit refers to the key frame information cycle by cycle in executing the trick play, and transmits the key frame having the offset closest to the delivery time among the key frames included in the contents file.
Claims7
A key frame delivery method of selecting key frames of a video file by a video delivery server connected over a network to a client device, where the video file is stored on a storage device, the key frame delivery method comprising the steps of:
- a) storing on the storage device, for each of the respective key frames included in the video file, key frame information including a key frame number that identifies the respective key frame, offset from the beginning of the video file, a relative delivery time of the key frame from the beginning of the video file in a case of delivering the video file at normal play and a size of the key frame;
- b) determining a cycle delivery time tk, where tk=T0+N×k×T and T0 is the relative start time of a trick play from the beginning of the video file, k is a cycle number of the trick play and N is a reproduction speed of the trick play;
- c) acquiring a key frame relative delivery time ij of a key frame lj prior and closest to the relative delivery time tk;
- d) acquiring a key frame relative delivery time ij+1 of a key frame lj+1 subsequent and closest to the relative delivery time tk;
- e) selecting, at the video delivery server, a key frame lk having the delivery time closest to the cycle delivery time tk, where lk is selected from among key frames lj and the lj+1 by comparing |tk−ij| with |ij+1−tk|;
- f) transmitting the selected key frame lk to the client device;
- g) incrementing the cycle number k;
- and
- h) repeating steps b) through g),
- wherein said |tk−ij| is an absolute difference between the relative delivery time tk and the key frame relative delivery time ij of the key frame lj prior and closest to the relative delivery time tk, and
- wherein said |ij+i−tk| is an absolute difference between the key frame relative delivery time ij+1 of the key frame lj+1 subsequent and closest to the relative delivery time tk.
A video delivery device, which enables a client device, connected to the video delivery device over a network, to achieve trick play by delivering key frames included in a video file, comprising:
- a storage device, which stores
- the video file, which includes a plurality of key frames, and
- key frame information including, with respect to each key frame, a key frame number that identifies the respective key frame in the video file, and a relative delivery time ij which indicates a relative delivery time of the j-th key frame lj from the beginning of the video file in case of delivering the video file at normal play;
- and
- a delivery control unit, which delivers said key frames in a predetermined cycle T in the trick play,
- wherein said delivery control unit, at a k-th cycle in the trick play, refers to the key frame information, selects a key frame which has a relative delivery time ik that is closest to the relative delivery time tk, where tk=T0+N×k×T and T0 is the relative start time of the trick play from the beginning of the video file and N is a reproduction speed of the trick play, depending on the reproduction speed, and transmits the selected key frame as the k-th key frame lk,
- wherein said delivery control unit selects the k-th key frame lk from key frames lj and lj+1 by comparing |tk−ij| with |ij+1−tk|,
- wherein said |tk−ij| is an absolute difference between the relative delivery time tk and a key frame relative delivery time ij of a key frame lj prior and closest to the relative delivery time tk,
- wherein said |ij+i−tk| is an absolute difference between a key frame relative delivery time ij+1 of a key frame lj+1 subsequent and closest to the relative delivery time tk, and
- wherein the key frame lk is selected as being closest in time to the relative delivery time tk depending to the reproduction speed at the k-th cycle.
Dependencies are inferred from the claim text.