Methods and systems for scalable video delivery
Methods and systems for delivering scalable media content from a server to a client are provided. A server index is provided to a media server for indexing the layers of scalable content in the form of media data groups. The client transmits at least one media request comprising a scalable media presentation identifier, a requested quality identifier and a requested layer identifier. Based on the at least one request, the server identifies the requested media data groups and transmits the requested media data groups to the client. The client receives the requested media data groups, which may be a subset of all available media data groups, and reorders the media data into decoding order for subsequent decoding and playback.
1. A system for delivering media content, the system comprising:
a server comprising a computer processor, the server configured to:
provide a plurality of network abstraction layer (NAL) units representing a scalable media presentation, each NAL unit being associated with one layer of a plurality of layers;
group the plurality of NAL units into a plurality of media data groups, each media data group corresponding to only one layer of the plurality of layers for a specific time period of the scalable media presentation;
provide a server index comprising a plurality of server index entries, each server index entry corresponding to only one of the plurality of media data groups and comprising a media data group identifier for identifying the corresponding media data group, a quality identifier for identifying a quality level of the corresponding media data group and a layer identifier for identifying the layer associated with the corresponding media data group;
a client, the client configured to:
receive a client index, the client index comprising a plurality of client index entries, each client index entry corresponding to only one of the server index entries;
determine a desired quality level for the specific time period of the scalable media presentation, based at least on an available bandwidth metric;
based on the client index, determine a subset of the plurality of layers required to reproduce the scalable media presentation at the desired quality level;
generate at least one media request corresponding to the subset of the plurality of layers, each of the at least one media request comprising a scalable media presentation identifier for identifying the scalable media presentation, a requested quality identifier and a requested layer identifier;
transmit the at least one media request to the server; and wherein the server is further configured to, for each at least one media request:
determine a requested index entry in the plurality of server index entries based on the scalable media presentation identifier, the requested quality identifier and the requested layer identifier;
identify a requested media data group based on the media data group identifier of the requested index entry; and
transmit the requested media data group to the client.
2. The system of claim 1 , wherein each of the plurality of NAL units in the specific time period has a sequence identifier associated therewith for identifying the decoding order of each NAL unit within the plurality of NAL units, and wherein each of the media data groups comprises decoding order data identifying the sequence identifier associated with each of the NAL units grouped in the media data group.
3. The system of claim 2 , wherein the subset of the plurality of layers comprises a plurality of layers, and wherein the client is further configured to:
receive the requested media data groups corresponding to the plurality of layers;
extract the decoding order data from the requested media data groups for each NAL unit contained in the requested media data groups;
reorder the NAL units according to the decoding order data; and
decode the NAL units in the order specified in the decoding order data.