Method and apparatus for smoothing and multiplexing video data flows
AssigneeAT&T Corp.
InventorsNicholas G. Duffield, Kadangode K. Ramakrishnan, Amy Ruth Reibman
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Abstract
A method and apparatus provide a smoothing and rate adaptation algorithm to facilitate the flow of video data, maintaining video quality while avoiding potentially harmful buffering delays. The invention uses a smoothing interval to determine a rate to request for allocation. The invention also adapts the encoding rate in relation to a target delay for a source buffer.
Claims28
A method for improving a flow of video data from a source to a receiver, the method comprising the steps of:
- encoding video data at a first rate;
- storing the encoded video data in a buffer;
- requesting a rate allocation from a network, wherein a request amount is determined with reference to said first rate and to a frame rate over a smoothing interval;
- outputting data from the source buffer at a rate based on the network's response to the request for a rate allocation;
- monitoring a source delay with reference to buffer capacity, buffer fill status, an encoding rate and a rate allocated to the source in response to a request;
- and
- adjusting a rate for encoding said video data when said monitoring step detects that said source delay exceeds a first threshold.
A method for improving a flow of video data from a source to a receiver, the method comprising the steps of:
- encoding video data;
- storing the coded data in a source buffer;
- monitoring a rate of the encoding of video data over a smoothing interval;
- determining a smoothed ideal encoding rate from the monitored rate;
- and
- generating a request for rate allocation with reference to the smoothed ideal rate.
A method for improving a flow of video data from a source to a receiver, the method comprising the steps of:
- encoding video data;
- monitoring an encoding rate over a first window interval, said first window interval being greater than or equal to a periodicity of the coded video data;
- monitoring the encoding rate over a second window interval, greater than said first window interval;
- and
- requesting a rate allocation from a network in accordance with the results of said monitoring steps.
A method for selecting a data rate allocation request with regard to a flow of video data from a source to a network, the method comprising the steps of:
- monitoring a rate of encoding video data;
- averaging the encoding rate over a smoothing interval equal to or greater than a periodicity the encoded video data;
- and
- calculating a rate allocation request using the result of the step of averaging.
A method of improving a quality of a flow of video data from a source to a receiver via a network, the method comprising the steps of:
- encoding the video data at a first rate;
- storing encoded video data in a source buffer;
- detecting a buffer drain rate;
- determining a source delay with reference to an encoding rate, a buffer drain rate and a buffer fill level;
- if said source delay exceeds a delay bound, setting an encoder target rate to reduce the source delay.
A method for improving a flow of video data from a source to a receiver, the method comprising the steps of:
- encoding video data;
- storing the coded video data in a buffer;
- monitoring a rate of encoding video data over a smoothing interval;
- selecting a data transmission rate based on the encoding rate detected over the smoothing interval.
Dependencies are inferred from the claim text.