Media file format to support switching between multiple timeline-altered media streams

• US 7,302,490 B1
• Filed: 05/03/2000
• Issued: 11/27/2007
• Est. Priority Date: 05/03/2000
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: He, Li-Wei, Gupta, Anoop, Omoigui, Nosakhare D.
• Primary Examiner(s): Sheikh; Ayaz
• Assistant Examiner(s): LAFORGIA, CHRISTIAN A
• Application Number:
  US09/564,297
• Time in Patent Office: 2,764 Days
• Field of Search: 709/231, 709/236, 709/219, 707/1, 707/512, 725/86, 725/87, 725/88, 725/90, 725/93, 725/94, 715/720, 386/68
• US Class Current: 709/231
• CPC Class Codes: H04L 65/764 at the destination reformatting of additional data in video clients H04N21/4355
• CPC Class Codes: H04N 21/2335 involving reformatting operations of audio signals, e.g. by converting from one coding standard to another details of audio signal transcoding G10L19/173
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/23439 for generating different versions
• CPC Class Codes: H04N 21/44016 involving splicing one content stream with another content stream, e.g. for substituting a video clip
• CPC Class Codes: H04N 21/8456 by decomposing the content in the time domain, e.g. in time segments
• CPC Class Codes: H04N 21/85406 involving a specific file format, e.g. MP4 format
• CPC Class Codes: H04N 21/858 Linking data to content, e.g. by linking an URL to a video object, by creating a hotspot
• CPC Class Codes: Y10S 707/99931 Database or file accessing

Abstract

In a networked client/server system, media content is streamed from a server computer to a client computer. A media file format is used to store data for multiple timeline-altered streams that provides support for switching between the different timeline-altered streams during their presentation. According to one embodiment, a time code stream includes multiple data objects mapping corresponding timeline-altered stream data units to primary stream presentation times, and an index table mapping primary stream presentation times to timeline-altered stream byte offsets.

Claims

1. A method at least partially implemented by a computer, the method comprising:

receiving a user selection to switch from a first timeline-altered media stream to a second timeline-altered media stream;

accessing a time-compressed stream object corresponding to a data unit, currently being rendered, of the first timeline-altered media stream;

identifying, from the time-compressed stream object, a presentation time of a primary media stream whose timeline has not been altered, the presentation time indicates when the data unit of the first timeline-altered media stream is to be rendered, the presentation time being independent of a delivery time that indicates when the data unit is to be delivered to a rendering client;

accessing an index table to identify an offset into the second timeline altered stream corresponding to the presentation time of the primary media stream; and

rendering or streaming the second timeline-altered media stream beginning at the location identified by the offset to present the second timeline-altered media stream to a user.

2. The method of claim 1, further comprising rendering the second timeline-altered media stream beginning at a location prior to the location identified by the offset.

3. The method of claim 1, further comprising streaming the second timeline-altered media stream, beginning at a location prior to the location identified by the offset, to a client computer for presentation to a user.

4. The method of claim 1, wherein the time-compressed stream object maps a presentation time of the data unit to the presentation time of the primary media stream.

5. A system comprising:

a sending computer coupled to a network;

a receiving computer coupled to a network;

wherein the sending computer is configured to transmit, to the receiving computer, a data stream having a plurality of data units, the data stream including a time code stream that includes, for each of the plurality of data units, a respective object that maps a current presentation time of the data unit to a corresponding current presentation time of a non-timeline altered primary data stream, the current presentation time being independent of a delivery time and indicating when the data unit is to be presented; and

wherein the receiving computer is configured to,

receive the data stream from the sending computer,

receive a user request to change from presentation of the data stream to presentation of another data stream, identify a current presentation time of the other data stream based on a mapping to the non-timeline altered primary data stream in the respective object corresponding to the data unit currently being rendered; and

render the other data stream for presentation to a user beginning at an offset into the other data stream, the offset being identified from the mapping.

6. The system of claim 5, wherein the sending computer is further configured to transmit, to the receiving computer, a media stream index having a plurality of data fields, each field including a mapping from a presentation time of the non-timeline altered primary data stream to a presentation time in a timeline-altered media stream.

7. The system of claim 6, wherein the receiving computer is further configured to identify the current presentation time of the other data stream by:

identifying the current presentation time of the non-timeline altered primary data stream from the mapping in the object corresponding to the data unit currently being rendered;

accessing the media stream index using the current presentation time of the non-timeline altered primary data stream to identify the presentation time in the timeline-altered stream.

8. The system of claim 5, wherein the data unit currently being rendered comprises the data unit being rendered at the time the user request is received.