DELIVERING CACHEABLE STREAMING MEDIA PRESENTATIONS

• US 20100235528A1
• Filed: 03/16/2009
• Published: 09/16/2010
• Est. Priority Date: 03/16/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Liu, Lin, Bocharov, John A., Gao, Jimin, Zhang, Geqiang (Sam), Roy, Anirban, Freelander, Jack E., Duggaraju, Krishna Prakash, Sirivara, Sudheer, Sood, Vishal, Knowlton, Christopher G.
• Granted Patent: US 8,909,806 B2
• Time in Patent Office: Days
• US Class Current: 709/231
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04L 65/613 for the control of the source by the destination control signals issued by the client directed to the server or network components specially adapted for selective content distribution H04N21/637
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/756 adapting media to device capabilities
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04L 65/765 intermediate
• CPC Class Codes: H04L 67/566 Grouping or aggregating service requests, e.g. for unified processing
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04N 21/6437 Real-time Transport Protocol [RTP]

Abstract

A smooth streaming system provides a stateless protocol between a client and server in which the server embeds incremental control information in media fragments. The server provides uniform media fragment responses to media fragment requests that are cacheable by existing Internet cache infrastructure. The smooth streaming system receives media data in fragments from one or more encoders, creates an index of each fragment, and stores the fragments. The server provides fragments to clients that contain metadata information describing the encodings available on the server and the encoding of the fragment. The server may also provide information within each fragment that allows the client to determine whether the client is requesting data too fast or too slow, so that the client can adapt its request rate to a cadence in tune with the rate at which the server is receiving encoder data.

Claims

1. A computer-implemented method for providing streaming media from a server to a client, the method comprising:

receiving a manifest request from the client;

building a client manifest to satisfy the client request based on media fragments and encoder information the server has received;

providing the built client manifest to the client in response to the manifest request;

receiving a fragment request from a client that identifies a particular media fragment;

building an incremental manifest by retrieving manifest information that describes the requested media fragment;

sending a response to the client fragment request that includes the requested media fragment and the built incremental manifest;

wherein the preceding steps are performed by at least one processor and wherein the server provides media fragments to multiple clients without storing state information regarding each of the clients.

2. The method of claim 1 wherein the manifest request determines one or more encodings of an event available from the server and information regarding existing media fragments related to the event, wherein the available encodings comprise multiple bit rates of media associated with the event between which a client can select at any point during playback.

3. The method of claim 1 wherein building a client manifest comprises parsing a server manifest from each encoder and merging received encoder manifests into the client manifest.

4. The method of claim 1 wherein the client manifest includes a static portion that is a union of each of multiple encoder manifests that describes available encodings, and a dynamic portion that describes media fragments received by the server from multiple encoders up to the point of the request, and wherein the client can start playback and respond to a seek by requesting one or more specific media fragments based on the client manifest.

5. The method of claim 1 wherein providing the client manifest comprises sending a cacheable HTTP response and wherein the cacheable HTTP response includes a cache lifetime based on a server-provided lifetime of the client manifest.

6. The method of claim 1 wherein the client can begin requesting fragments in one of multiple encodings based on the client manifest, and wherein the client can initially select a first low bit rate encoding and later requests fragments at a higher bit rate based on one or more detected conditions.

7. The method of claim 1 wherein the fragment request identifies a particular fragment by including a distinguished Uniform Resource Locator (URL) that identifies a time associated with the fragment and an encoding associated with the fragment.

8. The method of claim 1 wherein building an incremental manifest comprises including information regarding one or more media fragments subsequent to the requested media fragment.

9. The method of claim 1 wherein the initial manifest and the incremental manifest allow the client to build a local manifest that encompasses information regarding a complete media event and to skip around and play back any location within the media event.

10. A computer system for delivering cacheable streaming media presentations, the system comprising:

a processor and memory configured to execute software instructions;

a register event component configured to receive information regarding a live media event for which the system will receive encoded media data;

an encoder interface component configured to provide an interface between the system and one or more encoders that provide the encoded media data as media fragments;

an index fragment component configured to create and maintain an index table of media fragments received from encoders;

a fragment data store configured to store received media fragments and the created index table of fragments to provide to clients based on received client requests;

a client interface component configured to receive client requests for media fragments and provide manifest data and media fragments to clients;

a build client manifest component configured to build a manifest to satisfy a client request that includes information regarding each of the encodings available from the system and fragments stored by the system up to a time of the request; and

a clock synchronization component configured to synchronize the clocks of the system, clients, and encoders.

11. The system of claim 10 wherein the register event component is further configured to receive identifiers for each of multiple encoders that will supply encoded media data to the system.

12. The system of claim 10 wherein the encoder interface component receives pushed media data from the encoders through HTTP POST requests.

13. The system of claim 10 wherein the encoder interface component receives encoded media data in a media container that includes boxes for media information and media metadata.

14. The system of claim 10 wherein the index fragment component is further configured to keep track of which media fragments have been received and from which encoders based on a time stamp associated with each media fragment.

15. The system of claim 10 wherein the client interface component is further configured to receive an initial manifest request from a client connecting to the system, invoke the build client manifest component to create a client manifest that includes information regarding the encodings available from the system and fragments stored by the system up to a current time based on the index table, and provide the client manifest to the client.

16. The system of claim 10 wherein the build client manifest component is further configured to provide an incremental manifest to include with each requested media fragment, wherein the incremental manifest provides information to the client regarding the current media fragment as well as at least one subsequent media fragment.

17. The system of claim 10 wherein the build client manifest component is further configured to provide the client with a count of subsequent fragment that the client can expect with each media fragment as a timing hint for the client.

18. A computer-readable storage medium comprising instructions for controlling a computer system to receive encoded media fragments from one or more encoders, wherein the instructions, when executed, cause a processor to perform actions comprising:

receiving an event registration that describes a media event for which the system will receive media data from one or more encoders;

requesting a manifest from each registered encoder that describes the media data available from the encoder;

receiving an encoder manifest from each encoder;

receiving a media fragment from an encoder;

indexing the received media fragment and adding the index information to an index table that catalogs the available media fragments;

archiving the received media fragment by storing the fragment and index information in a data store from which the fragment and index information can later be retrieved to satisfy client requests; and

building a server manifest that includes information regarding a media event of which the media fragments are a part by adding information regarding the received fragment to the manifest.

19. The medium of claim 18 further comprising, for each received encoder manifest, merging the manifests of the encoders together and storing the merged manifest for later retrieval by clients to identify the media encodings that the system can provide.

20. The medium of claim 18 wherein the received media fragment includes a timestamp and an identifier of the encoder that encoded the media fragment, and wherein the system uses the timestamp associated with the media fragment to correlate media fragments produced in parallel by different encoders.