SMOOTH, STATELESS CLIENT MEDIA STREAMING

• US 20100235472A1
• 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: Duggaraju, Krishna, Liu, Lin, Bocharov, John A., Zhang, Geqiang (Sam), Roy, Anirban, Freelander, Jack E., Sirivara, Sudheer, Sood, Vishal
• Granted Patent: US 8,621,044 B2
• Time in Patent Office: Days
• US Class Current: 709/219
• 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 65/752 adapting media to network capabilities
• 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 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

An adaptive streaming system is described herein that provides a stateless connection between the client and server for streaming media playback in which the data is formatted in a manner that allows the client to make decisions and react more quickly to changing network conditions. The client requests uniform chunks of media from the server that include a portion of the media. The adaptive streaming system requests portions of a media file or of a live streaming event in small-sized chunks each having a distinguished URL. This allows streaming media data to be cached by existing Internet cache infrastructure. Each chunk contains metadata information that describes the encoding of the chunk and media content for playback by the client. The server may provide chunks in multiple encodings so that the client can switch quickly to chunks of a different bit rate or playback speed.

Claims

1. A computer-implemented method for smoothly playing media on a client, the method comprising:

sending from the client a request for a chunk of media to a server over a network, wherein the chunk comprises a uniform portion of the media available from the server to multiple clients;

receiving at the client the requested chunk;

parsing the chunk into a metadata portion and a media data portion;

adding the chunk metadata to an ongoing media manifest that describes information regarding a larger media element to which the media chunk belongs; and

playing the media data using a codec identified by the chunk metadata and hardware of the client,

wherein the preceding steps are performed by at least one processor.

2. The method of claim 1 wherein receiving at the client the request chunk comprises receiving the chunk from an Internet cache before the request reaches the server and storing the chunk in a client cache.

3. The method of claim 1 wherein parsing further comprises identifying metadata that describes the encoding of the chunk and media data suitable for playback using a codec and appropriate hardware.

4. The method of claim 1 wherein the client stores a manifest in memory that contains the metadata from each chunk of a media file.

5. The method of claim 1 wherein the chunk metadata portion includes information regarding at least one subsequent chunk available from the server.

6. The method of claim 1 further comprising determining a bit rate of a subsequent chunk to request, wherein the determined bit rate is based on a count of information regarding subsequent chunks in the chunk metadata portion.

7. A computer system for smoothly processing media from a live event, the system comprising:

a processor and memory configured to execute software instructions;

a chunk request component configured to make requests from a client for individual media chunks from an origin server, wherein the chunks represent portions of a media file available individually from the server;

a chunk parsing component configured to interpret a format of each media chunk received by the chunk request component and separate the chunk into component parts;

a manifest assembly component configured to build a manifest that describes a media element to which received media content chunks belong;

a media playback component configured to play back received media content chunks using client hardware;

a QoS monitoring component configured to analyze a result of receiving packets from the server and adapt client requests based on a set of current network conditions; and

a clock synchronization component configured to synchronize clocks of the server and the client so that the server and client can identify particular chunks based on time.

8. The system of claim 7 wherein the chunk request component requests chunks using HTTP GET requests.

9. The system of claim 7 wherein the chunk request component determines a user associated with the request and requests chunks based on a subscription level of the user.

10. The system of claim 7 wherein the client and origin server do not have a state-based connection between each other.

11. The system of claim 7 wherein the chunk request component identifies each chunk by a Uniform Resource Locator (URL) that individually identifies the chunk.

12. The system of claim 7 wherein the chunk parsing component separates the chunk into a header portion containing metadata and a data portion containing media content and wherein the chunk parsing component provides the metadata to the manifest assembly component and the media content to the media playback component and if the chunk contains non-audiovisual data parsing the chunk and consuming the non-audiovisual data.

13. The system of claim 7 wherein the manifest assembly component is further configured to include in the manifest information describing a codec and a bit rate used to encode each chunk.

14. The system of claim 7 wherein the manifest assembly component is further configured to receive requests to play a portion of the media element other than a current live position based on the manifest.

15. The system of claim 7 wherein the media playback component is further configured to invoke one or more codecs to interpret a container within which the media content is transported and to decompress media content from a compressed format contained in each media chunk.

16. The system of claim 7 wherein the QoS monitoring component is further configured to switch bit rates of the requested chunks by requesting chunks from a different server URL.

17. The system of claim 7 wherein the clock synchronization component is further configured to maintain a cadence of client requests to the server for subsequent media chunks.

18. A computer-readable storage medium comprising instructions for controlling a computer system to playback media on a client, wherein the instructions, when executed, cause a processor to perform actions comprising:

selecting an initial encoding at which to request encoded media from a server;

receiving a particular media chunk from the server;

playing the received media chunk;

determining a quality of service (QoS) metric based on the received chunk; and

upon determining that the QoS metric is too low and the client connection to the server cannot handle the current encoding,

selecting a second encoding of the encoded media, wherein the second encoding of the encoded media is encoded at a lower bit rate than the initial encoding.

19. The medium of claim 18 wherein selecting an initial bit rate comprises initially selecting a lowest available bit rate.

20. The medium of claim 18 further comprising, upon determining that the QoS metric is high, selecting a third encoding of the encoded media, where the third encoding is encoded at a higher bit rate than the initial encoding.