Method and system for stream handling using an intermediate format

Abstract

A method of delivering a live stream is implemented within a content delivery network (CDN) and includes the high level functions of recording the stream using a recording tier, and playing the stream using a player tier. The step of recording the stream includes a set of sub-steps that begins when the stream is received at a CDN entry point in a source format. The stream is then converted into an intermediate format (IF), which is an internal format for delivering the stream within the CDN and comprises a stream manifest, a set of one or more fragment indexes (FI), and a set of IF fragments. The player process begins when a requesting client is associated with a CDN HTTP proxy. In response to receipt at the HTTP proxy of a request for the stream or a portion thereof, the HTTP proxy retrieves (either from the archive or the data store) the stream manifest and at least one fragment index. Using the fragment index, the IF fragments are retrieved to the HTTP proxy, converted to a target format, and then served in response to the client request. The source format may be the same or different from the target format. Preferably, all fragments are accessed, cached and served by the HTTP proxy via HTTP.

1 . Apparatus, comprising:
 a set of interconnected machines, each machine comprising a processor, and computer memory for holding computer program instructions that when executed by the processor facilitate a method of managing a stream received in a source format, the method comprising:   demuxing the stream from the source format into an intermediate format comprising file fragments and associated index information, wherein a file fragment represents a given time period of the stream; and   in response to a request, and based on the associated index information, muxing the file fragments into a target format.   
     
     
         2 . The apparatus as described in  claim 1  wherein the intermediate format is a fragmented MP4 format. 
     
     
         3 . The apparatus as described in  claim 1  wherein the source format and the target format differ. 
     
     
         4 . The apparatus as described in  claim 1  wherein the intermediate format comprises a manifest, a set of one or more fragment indexes (FI), and a set of IF fragments, each IF fragment identified by a fragment number and comprising a header and a payload. 
     
     
         5 . The apparatus as described in  claim 4  wherein the manifest comprises stream metadata, and information about the one or more fragment indexes. 
     
     
         6 . The apparatus as described in  claim 4  wherein a fragment index comprises information identifying a key frame associated with a given time slice, a key frame-to-fragment number mapping, a key frame-to-time mapping, and a key frame-to-byte offset in a key frame-to-fragment number mapping. 
     
     
         7 . The apparatus as described in  claim 6  wherein the information enables a process executing on one of the interconnected machines to identify a key frame associated with a desired seek time in the stream. 
     
     
         8 . The apparatus as described in  4  wherein fragment numbers associated with a set of IF fragments are consecutive. 
     
     
         9 . The apparatus as described in  claim 1  wherein the muxing occurs at an HTTP proxy. 
     
     
         10 . The apparatus as described in  claim 9  retrieving the file fragments to the HTTP proxy in response to receipt of the request at the HTTP proxy. 
     
     
         11 . The apparatus as described in  claim 4  further including storing the manifest, the fragment indexes and the set of IF fragments