Caching and streaming of digital media content subsets

1. A method of operating a content node to provide a digital media caching environment, the method comprising:

receiving, by the content node, a request transferred by an end user device for digital media content;

retrieving, by the content node, a header portion for the digital media content from an origin server;

caching, by the content node, the header portion for the digital media content;

processing, by the content node, the header portion to determine a content subset of the digital media content that is associated with the request, wherein the content subset is a byte range corresponding to the request;

retrieving, by the content node, the content subset from the origin server and transmuxing the content subset of the digital media content into a stream format suitable for rendering by the end user device;

caching, by the content node, the retrieved content in its transmuxed format;

receiving a subsequent request for digital media content, wherein the subsequent request comprises a request for content in a second stream format;

processing, by the content node, the cached header portion to determine a subsequent content subset of the digital media content that is associated with the subsequent request for digital media content, wherein the second content subset comprises: a byte range corresponding to a portion of the cached transmuxed content, and non-cached content that precedes the cached transmuxed content;

re-transmuxing the portion of the cached transmuxed content corresponding to the subsequent request into the second stream format;

retrieving, by the content node, the non-cached content from the origin server, and transmuxing the non-cached content into the second stream format; and

streaming, by the content node, the re-transmuxed content corresponding to the second content subset in the second stream format, and the non-cached content retrieved from the origin server in the second stream format.

2. The method of claim 1 , wherein the header portion comprises a header of a file of the digital media content, and wherein the content subset comprises a byte range of media content included in the file of the digital media content.

3. The method of claim 1 , further comprising:

issuing at least a first Hypertext Transfer Protocol (HTTP) range request for delivery to the origin server to retrieve the header portion and issuing at least a second HTTP range request for delivery to the origin server to retrieve the content subset.

4. The method of claim 1 , wherein the digital media content comprises a video, a live broadcast, or an audio file.

5. The method of claim 1 , wherein the content subset of the digital media content comprises a timewise portion of the digital media content.

6. A content node comprising:

one or more non-transitory computer readable storage media;

a processing system communicatively coupled to the one or more non-transitory computer readable media;

program instructions stored on the one or more non-transitory computer readable storage media that, when read and executed by the processing system, direct the processing system to:

retrieve, by the content node, a request transferred by an end user device for digital media content;

retrieve, by the content node, a header portion of the digital media content from an origin server;

cache, by the content node, the header portion for the digital media content;

process, by the content node, the header portion to determine a content subset of the digital media content that is associated with the request, wherein the content subset is a byte range corresponding to the request;

retrieve, by the content node, the content subset of the digital media content and transmux the content subset of the digital media content into a stream format suitable for rendering by the end user device;

cache, by the content node, the retrieved content in its transmuxed format;

retrieve a subsequent request for digital media content, wherein the subsequent request comprises a request for content in a second stream format;

process, by the content node, the cached header portion to determine a subsequent content subset of the digital media content that is associated with the subsequent request for digital media content, wherein the second content subset comprises: a byte range corresponding to a portion of the cached transmuxed content, and non-cached content that precedes the cached transmuxed content;

re-transmux the portion of the cached transmuxed content corresponding to the subsequent request into the second stream format;

retrieve, by the content node, the non-cached content from the origin server, and transmux the non-cached content into the second stream format; and

stream, by the content node, the re-transmuxed content corresponding to the second content subset in the second stream format, and the non-cached content retrieved from the origin server in the second stream format.

7. The content node of claim 6 , wherein the header portion comprises a header of a file of the digital media content, and wherein the content subset comprises a byte range of media content included in the file of the digital media content.

8. The content node of claim 6 , wherein the program instructions further direct the processing system to issue at least a first Hypertext Transfer Protocol (HTTP) range request for delivery to the origin server to retrieve the header portion and issue at least a second HTTP range request for deliver to the origin server to retrieve the content subset.

9. The content node of claim 6 , wherein the digital media content comprises a video, a live broadcast, or an audio file.

10. The content node of claim 6 , wherein the content subset of the digital media content comprises a timewise portion of the digital media content.