Methods and systems for video streaming with VCR functionality

• US 6,738,980 B2
• Filed: 11/15/2001
• Issued: 05/18/2004
• Est. Priority Date: 11/15/2001
• Status: Expired due to Term

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Sun, Ming-Ting, Hsu, Hung-Hseng, Lin, Chia-Wen
• Primary Examiner(s): Miller, John
• Assistant Examiner(s): Sloan, Nathan A
• Application Number:
  US09/987,647
• Publication Number:
  US 20030093801A1
• Time in Patent Office: 915 Days
• Field of Search: 725/87, 725/88-100, 725/102, 725/103
• US Class Current: 725/88
• CPC Class Codes: H04N 21/231 Content storage operation, e.g. caching movies for short term storage, replicating data over plural servers, prioritizing data for deletion
• CPC Class Codes: H04N 21/2343 involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements video transcoding H04N19/40; media packet handling at the source H04L65/762
• CPC Class Codes: H04N 21/6587 Control parameters, e.g. trick play commands, viewpoint selection
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends
• CPC Class Codes: H04N 9/8042 involving data reduction
• CPC Class Codes: H04N 9/8227 the additional signal being at least another television signal

Abstract

Methods and systems for providing a video stream from a server to a client over a network include a memory for storing a forward-encoded bit-stream and a reverse-encoded bit-stream for a video data. The forward-encoded bit-stream includes I-frames encoded without inter-frame dependencies and P-frames encoded depending on forward-direction preceding frames, and the reverse-encoded bit-stream includes I-frames and P-frames encoded depending on reverse-direction preceding frames. When the server receives a request with a video cassette recording (VCR) function from the client, the server reads out and transmits frames selectively from among the first, second, third, and fourth frames in accordance with the request. The server can select the closest I-frame to a requested frame in either bit-stream for a fast-mode play or a random-access play, and switch the bit-streams to use subsequent P-frames in a different direction than that of the closest I-frame.

Claims

1. A method of providing an encoded video stream to a client over a network, the method comprising:

storing a forward-encoded bit-stream and a reverse-encoded bit-stream for video data, the forward-encoded bit-stream including first frames encoded without inter-frame dependencies and second frames encoded depending on forward-direct preceding frames, and the reverse-encoded bit-stream including third frames encoded without inter-frame dependencies and fourth frames encoded depending on reverse-direction preceding frames;

receiving a request with a video cassette recording (VCR) function from the client;

examining costs of decoding a requested frame in a forward direction from one of the first and third frames, in a reverse direction from another one of the first and third frames, and in either the forward or reverse direction from a current frame;

selecting a frame with a least cost among said one of the first and third frames, said another one of the first and third frames, and said current frame;

switching the forward-encoded and reverse-encoded bit streams, if the frame with the least cost belongs to a different bit-stream than the requested frame;

selecting one or more succeeding frames until reaching the requested frame among the second or the fourth frames;

reading out selected frames among the first, second, third, and fourth frames in accordance with the request; and

transmitting the selected frames to the client.

2. The method of claim 1, further comprising:

storing at least one drift-compensation bit-stream for the video data, the drift-compensation bit-stream including prediction of frames in the forward-encoded bit-stream from frames in the reverse-encoded bit-stream and prediction of frames in the reverse-encoded bit-stream from frames in the forward-encoded bit-stream; and

substituting, after the switching, a frame of the drift-compensation bit-stream for one of the second or the fourth frames.

3. A method of providing an encoded video stream to a client over a network, the method comprising:

storing a forward-encoded bit-stream and a reverse-encoded bit-stream for video data, the forward-encoded bit-stream including first frames encoded without inter-frame dependencies and second frames encoded depending on forward-direct preceding frames, and the reverse-encoded bit-stream including third frames encoded without inter-frame dependencies and fourth frames encoded depending on reverse-direction preceding frames;

receiving a request with a video cassette recording (VCR) function from the client;

selecting a closest one of the first and third frames to a requested frame when the VCR function of the request is a fast-mode play;

switching the forward-encoded and reverse-encoded bit-streams, if the closest frame belongs to a different bit-stream than the requested frame;

selecting one or more succeeding frames until reaching the requested frame among the second or the fourth frames;

reading out selected frames among the first, second, third, and fourth frames in accordance with the request; and

transmitting the selected frames to the client.

4. The method of claim 3, further comprising:

storing a first drift-compensation frame for predicting a reverse-direction succeeding frame from each of the first frames of the forward-encoded bit-stream, and a second drift-compensation frame for predicting a forward-direction succeeding frame from each of the third frames of the reverse-encoded bit-stream; and

substituting, after the switching, the first drift-compensation frame for one of the fourth frames, or the second drift-compensation frame for one of the second frames.