Enabling Trick Plays during VBR Playback of a CBR Transmitted Media File

• US 20090161765A1
• Filed: 12/21/2007
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Brown, Chris, Ulm, John, Joyce, Gerald, Patrick, Michael
• Granted Patent: US 8,468,571 B2
• Time in Patent Office: Days
• US Class Current: 375/240.230
• CPC Class Codes: H04N 21/8453 by locking or enabling a set of features, e.g. optional functionalities in an executable program
• CPC Class Codes: H04N 21/8455 involving pointers to the content, e.g. pointers to the I-frames of the video stream
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 9/8042 involving data reduction

Abstract

A method and system for enabling trick plays during a variable bit rate (VBR) playback of a media file transmitted to a user media device as a constant bit rate (CBR) flow includes determining a plurality of access points within the media file. The media file is configured to be played back from each of the plurality of access points. A minimum buffer value is calculated for each of the plurality of access points. The minimum buffer value identifies a minimum amount of the media file to transmit to the user media device before beginning playback of the media file from each of the plurality of access points to substantially ensure that the media file is configured to be played back from each of the plurality of access points continuously and uninterruptedly at a variable bit rate.

Claims

1. A method for enabling trick plays during a variable bit rate (VBR) playback of a media file transmitted to a user media device as a constant bit rate (CBR) flow, said method comprising:

determining a plurality of access points within the media file, wherein the media file is configured to be played back from each of the plurality of access points; and

calculating a minimum buffer value for each of the plurality of access points, wherein the minimum buffer value identifies a minimum amount of the media file to transmit to the user media device before beginning playback of the media file from each of the plurality of access points to substantially ensure that the media file is configured to be played back from each of the plurality of access points continuously and uninterruptedly at a variable bit rate.

2. The method of claim 1, further comprising:

storing the minimum buffer values for each of the plurality of access points with the media file.

3. The method of claim 1, further comprising:

receiving a selection of one of the plurality of access points; and

transmitting the minimum amount of the media file from the selected one of the plurality of access points to the user media device before playback of the media file from the selected one of the plurality of access points begins.

4. The method of claim 3, further comprising;

transmitting a control signal to the user media device while transmitting the minimum amount of the media file, wherein the control signal instructs the user media device to delay playback of the media file until the minimum amount of the media file has buffered to the user media device.

5. The method of claim 3, further comprising:

transmitting an additional amount of the media file to the user media device after playback of the media file has begun from the selected one of the plurality of access points.

6. The method of claim 1, wherein transmitting the minimum amount of the media file to the user media device comprises transmitting the media file downstream in a hybrid fiber-coaxial cable (HFC) network to the user media device.

7. The method of claim 1, wherein transmitting the minimum amount of the media file to the user media device comprises transmitting the media file as a CBR flow and playing back the media file from the user media device to a display device as a VBR flow.

8. The method of claim 1, wherein determining a plurality of access points comprises at least one of

identifying access points which have been previously determined;

and

dividing the media file into segments, wherein a beginning of each of the segments substantially corresponds to an access point.

9. The method of claim 1, wherein calculating a minimum buffer value for each of the plurality of access point further comprises:

determining a download bandwidth for the media file as a CBR flow; and

determining a duration of time to buffer the media file before beginning playback of the media file from each of the plurality of access points.

10. The method of claim 1, wherein calculating a minimum buffer value for each of the plurality of access point further comprises:

determining multiple download bandwidths for the media file as a CBR flow; and

determining a duration of time to buffer the media file for each of the multiple download bandwidths before beginning playback of the media file from each of the plurality of access points.

11. The method of claim 1, further comprising:

receiving a request for the media file through a video on demand (VoD) service.

12. A system for enabling trick plays during a VBR playback of a media file transmitted to a user media device as a CBR flow comprising:

a minimum buffer calculator operable to calculate minimum buffer values for each of a plurality of access points within the media file, wherein the minimum buffer value identifies a minimum amount of the media file to transmit to the user media device before beginning playback of the media file from each of the plurality of access points to ensure that the media file is configured to be played back from each of the plurality of access points continuously and uninterrupted at a variable bit rate.

13. The system of claim 12, further comprising:

a divider operable to divide the media file into a plurality of segments, wherein each of the plurality of access points substantially correspond to a beginning of each of the plurality of segments.

14. The system of claim 12, wherein each of the plurality of access points may be selected by a user to begin playback of the media file from the selected access point.

15. The system of claim 12, wherein the user media device includes at least one of a STB and a DVR and, wherein the media file is configured to be transmitted downstream over an HFC network to the user media device as a CBR flow and played back from the user media device to a display device as a VBR flow.

16. The system of claim 12, wherein minimum buffer values include a download bandwidth for the media file as a CBR flow and a duration of time to buffer the media file before beginning playback of the media file from each of the plurality of access points.

17. The system of claim 12, further comprising:

a storage device configured to store the media file and the minimum buffer values with the media file.

18. The system of claim 12, wherein the media file is selected by a user through a VoD service.

19. A computer readable medium storing one or more computer programs including instructions that when executed perform a method of enabling trick plays during a VBR playback of a media file transmitted to a user media device as a CBR flow, the method comprising:

determining a plurality of access points within the media file, wherein the media file is configured to be played back from each of the plurality of access points; and

calculating a minimum buffer value for each of the plurality of access points, wherein the minimum buffer value identifies a minimum amount of the media file to transmit to the user media device before beginning playback of the media file from each of the plurality of access points to ensure that the media file is played back from each of the plurality of access points continuously and uninterrupted at a variable bit rate.

20. The computer readable medium of claim 19, the method further comprises:

determining a download bandwidth for the media file as a CBR flow; and

determining a duration of time to buffer the media file before beginning playback of the media file from each of the plurality of access points.