Statistical multiplexing with heterogeneous encoder pool

1. A method of statistical multiplexing digital video, comprising:

loading a mapping curve into memory at a statistical multiplexor controller for each of a plurality of encoders in a heterogeneous encoder pool, each said mapping curve being specific to a type and/or configuration of encoder and associating target bitrates with need parameter values;

receiving a need parameter value at said statistical multiplexor controller from each encoder in said heterogeneous encoder pool;

determining a target bitrate associated with each need parameter value received at said statistical multiplexor controller, by looking up target bitrates for each need parameter on mapping curves specific to each encoder in said heterogeneous encoder pool;

sending said target bitrate from said statistical multiplexor controller to each encoder in said heterogeneous encoder pool in a bitrate assignment;

generating, with said statistical multiplexor controller, a new mapping curve for a new encoder when said new encoder is not recognized by said statistical multiplexor controller, by copying a default mapping curve;

sending bitrate assignments to said new encoder with target bitrates associated with need parameter values received from said new encoder on said new mapping curve;

determining an estimated video quality level of said new encoder's output stream with said statistical multiplexor controller, using an objective computational video model; and

refining said new mapping curve when the estimated video quality level of the encoder's output stream is higher or lower than a predefined optimal level, by increasing or decreasing the target bitrate for particular need parameter values on said new mapping curve.

2. The method of claim 1 , further comprising adjusting said target bitrate for each encoder such that a sum of target bitrates sent in bitrate assignments is substantially equal to a total aggregate bitrate.

3. The method of claim 1 , wherein said heterogeneous encoder pool comprises remote encoders in data communication with said statistical multiplexor controller over a network.

4. The method of claim 1 , wherein said heterogeneous encoder pool comprises a plurality of encoders of different types and/or configurations.

5. The method of claim 1 , further comprising determining an end-to-end delay in communications between said statistical multiplexor controller and said new encoder, and determining said estimated video quality level after waiting for said end-to-end delay following sending a bitrate assignment.

6. The method of claim 1 , wherein said default mapping curve is an optimal mapping curve previously provided to said statistical multiplexor controller.

7. The method of claim 1 , wherein said default mapping curve is an existing mapping curve stored at said statistical multiplexor controller for an encoder of a similar type and/or configuration as said new encoder.

8. A statistical multiplexing system, comprising:

a plurality of encoders in a heterogeneous encoder pool configured to accept encoders of any type and/or configuration, each of said plurality of encoders being configured to encode a different input video into an output stream;

a statistical multiplexor controller in remote and/or direct communication with each of said plurality of encoders, said statistical multiplexor controller being configured to:

load a mapping curve specific to each of said plurality of encoders that relates target bitrates to need parameter values;

receive need parameters from each of said plurality of encoders that indicate a complexity level of the encoder's input video;

send a bitrate assignment to each of said plurality of encoders in response to receipt of a need parameter, each bitrate assignment indicating a target bitrate from a particular mapping curve specific to a particular encoder that is associated with a particular need parameter value received from that particular encoder;

generate a new mapping curve for a new encoder that was previously unknown to the statistical multiplexor controller by copying a default mapping curve;

send bitrate assignments to said new encoder with target bitrates associated with need parameter values received from said new encoder on said new mapping curve;

determine an estimated video quality level of said new encoder's output stream, using an objective computational video model; and

refine said new mapping curve when the estimated video quality level of the encoder's output stream is higher or lower than a predefined optimal level, by increasing or decreasing the target bitrate for particular need parameter values on said new mapping curve.

9. The statistical multiplexing system of claim 8 , further comprising a multiplexor configured to receive the output streams from each of said plurality of encoders and combine them into a transport stream sent to one or more downstream decoding devices.

10. The statistical multiplexing system of claim 8 , wherein said statistical multiplexor controller is configured to adjust said target bitrate for each encoder such that a sum of target bitrates sent in bitrate assignments is substantially equal to a total aggregate bitrate.

11. The statistical multiplexing system of claim 8 , wherein said statistical multiplexor controller is further configured to determine an end-to-end delay in communications between said statistical multiplexor controller and said new encoder, and determine said estimated video quality level after waiting for said end-to-end delay following sending a bitrate assignment.

12. The statistical multiplexing system of claim 8 , wherein said default mapping curve is an optimal mapping curve previously provided to said statistical multiplexor controller.

13. The statistical multiplexing system of claim 8 , wherein said default mapping curve is an existing mapping curve stored at said statistical multiplexor controller for an encoder of a similar type and/or configuration as said new encoder.