Progressive download gateway
Embodiments disclosed herein relate to a gateway for delivering scalable media files from a web server to a client in a manner that allows dynamic thinning. The gateway includes a control module for receiving a request for a scalable media file, forwarding the request to a web server, receiving the scalable media file from the web server using a first protocol, transmitting a redirect message to the client, and receiving a streaming request from the client in response; a packet processor for packetizing the scalable media file to produce raw scalable media packets; an encapsulation module for encapsulating the raw scalable media packets using a second protocol to produce encapsulated scalable media packets; and an output module for streaming the encapsulated scalable media packets to the client in response to the streaming request. The gateway may also include a module for thinning the raw scalable media packets prior to encapsulation.
1. A gateway device for delivering a scalable media file from a web server to a media client over a network, the gateway device comprising:
(a) a control module for:
(i) receiving, using a first protocol, a progressive download request from the media client for the scalable media file;
(ii) forwarding the request to the web server;
(iii) receiving the scalable media file from the web server in response to the progressive download request, the scalable media file being encapsulated using the first protocol;
(iv) transmitting an HTTP redirect message to the media client, wherein the HTTP redirect message instructs the media client to replace the progressive download request for the scalable media file with a streaming request for the scalable media file addressed to the gateway device; and
(v) receiving, using a second protocol, the streaming request from the media client in response to the HTTP redirect message; and
(b) a buffer module for storing the scalable media file;
(c) a packet processor module for reading the scalable media file from the buffer module and packetizing the scalable media file to produce a plurality of raw scalable media packets;
(d) an encapsulation module for encapsulating a plurality of processed scalable media packets using the second protocol to produce a plurality of encapsulated scalable media packets, the plurality of processed scalable media packets being at least a portion of the plurality of raw scalable media packets; and
(e) an output module for streaming a plurality of output scalable media packets to the media client using the second protocol, in response to the streaming request, the output scalable media packets being at least a portion of the plurality of encapsulated scalable media packets.
2. The gateway device of claim 1 , further comprising a thinning module for thinning the plurality of raw scalable media packets to produce the plurality of processed scalable media packets.
3. The gateway device of claim 2 , wherein the thinning includes dynamic thinning.
4. The gateway device of claim 3 , wherein dynamic thinning comprises thinning performed in response to dynamic feedback received from at least one of the gateway device, the media client and the network.
5. The gateway device of claim 4 , wherein the dynamic feedback indicates available network bandwidth between the gateway device and the media client.
6. The gateway device of claim 5 , wherein the dynamic feedback comprises at least one RTCP message.
7. The gateway device of claim 2 , wherein the thinning includes steady state thinning.
8. The gateway device of claim 7 , wherein steady state thinning comprises thinning performed to achieve a steady state operational point, the steady state operational point defining a resolution, frame rate and quality level for the scalable media file.
9. The gateway device of claim 8 , wherein the steady state operational point is based on at least one of
an initial available network bandwidth between the gateway device and the media client;
a resolution, frame rate and quality level specified by the media client;
a profile of the media client; and
a defined set of policies.
10. The gateway device of claim 2 , wherein the gateway device further comprises a dynamic policy management module for defining a set of policies, and the thinning module performs the thinning in accordance with the set of policies.
11. The gateway device of claim 1 , further comprising a policing module for performing policing on the plurality of encapsulated scalable media packets to produce the plurality of output scalable media packets.
12. The gateway device of claim 11 , wherein policing comprises at least one of rate shaping, quality of service, and forward error correction.
13. The gateway device of claim 1 , wherein the first protocol is HTTP, and the second protocol is RTSP/RTP.
14. The gateway device of claim 1 , wherein the HTTP redirect message comprises address information for the gateway device and a session identifier, and the streaming request comprises the session identifier.
15. The gateway device of claim 14 , wherein the session identifier provides a link between the progressive download request and the streaming request.
16. The gateway device of claim 1 , wherein the plurality of raw scalable media packets are network abstraction layer packets.
17. The gateway device of claim 1 , wherein the scalable media file is a scalable video coding file.
18. A method for delivering a scalable media file from a web server to a media client over a network, the method comprising, at a gateway device:
(a) receiving, using a first protocol, a progressive download request from the media client for the scalable media file;
(b) forwarding the request to the web server;
(c) receiving the scalable media file from the web server in response to the progressive download request, the scalable media file being encapsulated using the first protocol;
(d) transmitting an HTTP redirect message to the media client, wherein the HTTP redirect message instructs the media client to replace the progressive download request for the scalable media file with a streaming request for the scalable media file addressed to the gateway device;
(e) performing packetization on the scalable media file to produce a plurality of raw media packets;
(f) encapsulating a plurality of processed scalable media packets using a second protocol to produce a plurality of encapsulated scalable media packets, the processed media packets comprising at least a portion of the raw scalable media packets; and
(g) streaming, using the second protocol, a plurality of output scalable media packets to the media client in response to the streaming request from the media client, the output scalable media packets being at least a portion of the plurality of encapsulated scalable media packets.
19. The method of claim 18 , further comprising thinning the plurality of raw scalable media packets to produce the plurality of processed scalable media packets.
20. The method of claim 19 , wherein thinning includes dynamic thinning.
21. The method of claim 20 , wherein dynamic thinning comprises thinning performed in response to dynamic feedback received from at least one of the gateway, the media client and the network.
22. The method of claim 21 , wherein the dynamic feedback indicates available network bandwidth between the gateway and the media client.
23. The method of claim 22 , wherein the dynamic feedback comprises at least one RTCP message.
24. The method of claim 19 , wherein thinning includes steady state thinning.
25. The method of claim 24 , wherein steady state thinning comprises thinning performed to achieve a steady state operational point, the steady state operational point defining a resolution, frame rate and quality level for the scalable media file.
26. The method of claim 25 , wherein the steady state operational point is based on at least one of
an initial available network bandwidth between the gateway and the media client;
a resolution, frame rate and quality level specified by the media client;
a profile of the media client; and
a defined set of policies.
27. The method of claim 19 , wherein the thinning is performed in accordance with a set of dynamic policies.
28. The method of claim 18 , further comprising performing policing on the plurality of encapsulated scalable media packets to produce the plurality of output scalable media packets.
29. The method of claim 28 , wherein policing comprises at least one of rate shaping, quality of service, and forward error correction.
30. The method of claim 18 , wherein the first protocol is HTTP and the second protocol is RTSP/RTP.
31. The method of claim 18 , wherein the HTTP redirect message comprises address information for a gateway and a session identifier, and the streaming request comprises the session identifier.
32. The method of claim 31 , wherein the session identifier provides a link between the progressive download request and the streaming request.
33. The method of claim 18 , wherein the plurality of raw scalable media packets are network abstraction layer packets.
34. The method of claim 18 , wherein the scalable media file is a scalable video coding file.