Method and apparatus of visual feedback for latency in communication media

1. A method performed in a communication terminal, comprising:

obtaining an estimate of latency in a conversation between a local speaker and each of one or more remote speakers separated from the local speaker by a communication medium;

obtaining a timing indication of at least an end of a conversational turn vocalized by the local speaker;

displaying an outbound graphical indication of progress of at least the end-of-turn across the communication medium toward at least a given one of said remote speakers with a transit time across the medium derived from the latency estimate;

estimating, from the latency estimate, an arrival time at which at least the given remote speaker will receive the end-of-turn;

imputing a conversational turn vocalized by at least the given remote speaker, including a start-of-turn imputed from the pertinent arrival time; and

displaying an inbound graphical indication of progress, across the communication medium toward the local speaker, of at least the start-of-turn from at least the given remote speaker with a transit time across the medium derived from the latency estimate.

2. The method of claim 1 , wherein the step of obtaining a timing indication comprises detecting at least a portion of at least one conversational turn vocalized by the local speaker, wherein the detected portion includes an end-of-turn.

3. The method of claim 2 , wherein:

the step of obtaining a timing indication comprises detecting both a start and an end of the conversational turn vocalized by the local speaker; and

the outbound displaying step comprises displaying a graphical indication of progress of both the start and the end of said local conversational turn.

4. The method of claim 1 , wherein the conversation is between the local speaker and one remote speaker.

5. The method of claim 1 , wherein the conversation is between the local speaker and a plurality of remote speakers, and the steps of latency estimation, outbound display, arrival-time estimation, speech-turn imputation, and inbound display are performed for each remote speaker in the plurality.

6. The method of claim 1 , wherein:

the detecting step comprises obtaining timing indications of both a start and an end of the conversational turn vocalized by the local speaker; and

the outbound displaying step comprises displaying a graphical indication of progress of both the start and the end of said local conversational turn.

7. The method of claim 6 , wherein:

the method further comprises detecting an end of the conversational turn vocalized by at least the given remote speaker; and

the inbound displaying step comprises continuously displaying an inbound graphical indication of progress only until said remote end-of-turn is detected.

8. The method of claim 1 , wherein the latency estimate is obtained from an echo canceller in the communication terminal.

9. The method of claim 1 , wherein the latency estimate is obtained from a processor, and the method further comprises:

identifying occurrences of conversational events of one or more types in a portion of the conversation having a duration;

measuring a fraction of the duration during which each said event type occurs; and

in the processor, computing the latency estimate from said measured fraction or fractions.

10. The method of claim 1 , wherein the latency estimate is obtained from a processor, and the method further comprises:

obtaining an indicator of a local time of an end-of-turn from the local speaker;

then obtaining an indicator of a local time of arrival of the next start-of-turn from a remote speaker; and

in the processor, estimating the latency from the difference between the times of said local end-of-turn and the arrival of said remote start-of-turn.

11. The method of claim 1 , wherein the latency estimate is an estimate of the time for speech to undergo a round-trip through the communication medium from the local speaker to a remote speaker and back, and the outbound and inbound graphical indications of progress are displayed with transit times of one-half the estimated round-trip time.

12. Apparatus, comprising:

a circuit configured to provide an estimate of latency in a conversation between a local speaker and at least one remote speaker separated from the local speaker by a communication medium;

a speech detection circuit configured to detect speech vocalized by the local speaker and to provide an indication of at least an end of a conversational turn taken by the local speaker;

an estimator configured for estimating, from the latency estimate, an arrival time at which the remote speaker will receive the end-of-turn;

a display generator; and

a display;

wherein the display generator is configured to generate, on the display, an outbound graphical indication of progress of at least the end-of-turn across the communication medium toward the remote speaker with a transit time across the medium derived from the latency estimate;

wherein the display generator is further configured to generate, on the display, an inbound graphical indication of progress, across the communication medium toward the local speaker, of at least a start of a conversational turn imputed to the remote speaker; and

wherein the display generator is further configured to start the display of the conversational turn imputed to the remote speaker at a time derived from the estimated time at which the remote speaker receives the local speaker's end-of-turn, and to progress the display of at least the remote speaker's start-of-turn across the communication medium with a transit time derived from the latency estimate.

13. The apparatus of claim 12 , wherein the circuit configured to provide an estimate of latency comprises an echo canceller.

14. The apparatus of claim 12 , wherein:

the circuit configured to provide an estimate of latency comprises a processor, and the processor is configured to:

identify occurrences of conversational events of one or more types in a portion of the conversation having a duration;

measure a fraction of the duration during which each said event type occurs; and

compute the latency estimate from said measured fraction or fractions.

15. The apparatus of claim 12 , wherein the circuit configured to provide an estimate of latency comprises a processor, and the processor is configured to:

obtain an indicator of a local time of an end-of-turn from the local speaker;

obtain an indicator of a local time of arrival of the next start-of-turn from a remote speaker; and

estimate the latency from the difference between the times of said local end-of-turn and the arrival of said remote start-of-turn.

16. The apparatus of claim 12 , wherein the latency estimate is an estimate of the time for speech to undergo a round-trip through the communication medium from the local speaker to a remote speaker and back, and the display generator is configured to display the outbound and inbound graphical indications of progress with transit times of one-half the estimated round-trip time.