Smoothing brightness transition during channel change

1. A computer memory that is not a transitory signal and that comprises instructions executable by at least one processor to:

access first and second brightness metadata pertaining to respective s and second contents;

responsive to receiving a command to change presentation from the first content to the second content, establish a composite brightness using the first and second metadata;

present at least one of the contents using the composite brightness at a start time of a transition period;

during the transition period, present video using a changing brightness that starts at the composite brightness at the start time of the transition period and ends at the second brightness at an end time of the transition period; and

subsequent to the end time of the transition period, present the second content using the second metadata and not using the first metadata, wherein the first and second brightness metadata include respective first and second peak and average brightness values, and the composite brightness includes a composite peak brightness value derived from the first and second peak brightness values.

2. The computer memory of claim 1 , wherein the presentation brightness changes continuously from the start time to the end time of the transition period.

3. The computer memory of claim 2 , wherein the presentation brightness changes continuously from the start time to the end time of the transition period such that the presentation brightness during the transition period is characterized by at least three successive, different brightnesses.

4. A computer memory that is not a transitory signal and that comprises instructions executable by at least one processor to:

access first and second brightness metadata pertaining to respective first and second contents;

responsive to receiving a command to change presentation from the first content to the second content, establish a composite brightness using the first and second metadata;

present at least one of the contents using the composite brightness at a start time transition period;

during the transition period, present video using a changing brightness that starts at the composite brightness at the start time of the transition period and ends at the second brightness at an end time of the transition period; and

subsequent to the end time of the transition period, present the second content using the second metadata and not using the first metadata, wherein the composite brightness is an average of the first and second brightness metadata.

5. A computer memory that is not a transitory signal and that comprises instructions executable by at least one processor to:

access first and second brightness metadata pertaining to respective first and second contents;

responsive to receiving a command to change presentation from the first content to the second content, establish a composite brightness using the first and second metadata;

present at least one of the contents using the composite brightness at a start time of a transition period;

during the transition period, present video using a changing brightness that starts at the composite brightness at the start time of the transition period and ends at the second brightness at an end time of the transition period; and

subsequent to the end time of the transition period, present the second content using the second metadata and not using the first metadata, wherein the first and second brightness metadata include respective first and second peak and average brightness values, and the composite brightness includes an average brightness value derived from the first and second average brightness values, wherein the composite brightness further includes a composite peak brightness value derived from the first and second peak brightness values.

6. The computer memory of claim 1 , wherein the instructions are executable to present only the first content during the transition period and to change presentation from the first content to the second content at the end time of the transition period.

7. The computer memory of claim 1 , wherein the instructions are executable to present only the second content during the transition period and to change presentation from the first content to the second content at the start time of the transition period.

8. The computer memory of claim 1 , wherein the instructions are executable to present both the first content and the second content during the transition period and to change presentation from the first content to the second content during the transition period, between the start time and the end time thereof.

9. An assembly, comprising:

at least one processor;

at least one video display configured to be controlled by the processor; and

at least one computer memory with instructions executable by the at least one processor to:

receive a command to change presentation of video from a first content to a second content;

responsive to the content change command, present video on the display using a continuously variable brightness during a transition period;

access first and second brightness metadata in respective first and second contents;

responsive to receiving the command, establish a composite brightness using the first and second metadata;

present at least one of the contents using the composite brightness at a start time of the transition period;

during the transition period, present video using the continuously variable brightness that starts at the composite brightness at the start time of the transition period and ends at the second brightness at an end time of the transition period; and

subsequent to the end time of the transition period, present the second content using the second metadata and not using the first metadata, wherein the first and second brightness metadata include respective first and second peak and average brightness values, and the composite brightness includes a composite peak brightness value derived from the first and second peak brightness values.

10. The assembly of claim 9 , wherein the composite brightness is an average of the first and second brightness metadata.

11. An assembly, comprising:

at least one processor;

at least one video display configured to be controlled by the processor; and

at least one computer memory with instructions executable by the at least one processor to:

receive a command to change presentation of video from a first content to a second content;

access first and second brightness metadata in respective first and second contents;

responsive to receiving the command to change presentation, establish a composite brightness using the first and second metadata;

present at least one of the contents using the composite brightness at a start time of the transition period;

during the transition period, present video using the continuously variable brightness that starts at the composite brightness at the start time of the transition period and ends at the second brightness at an end time of the transition period; and

subsequent to the end time of the transition period, present the second content using the second metadata and not using the first metadata, wherein the first and second brightness metadata include respective first and second peak and average brightness values, and the composite brightness includes an average brightness value derived from the first and second average brightness values.

12. The assembly of claim 11 , wherein the composite brightness further includes a composite peak brightness value derived from the first and second peak brightness values.

13. An assembly, comprising:

at least one processor;

at least one video display configured to be controlled by the processor; and

at least one computer memory with instructions executable by the at least one processor to:

receive a command to change presentation of video from a first content to a second content;

responsive to the content change command, present video on the display using a continuously variable brightness during a transition period, wherein the instructions are executable to present only the first content during the transition period and to change presentation from the first content to the second content at the end time of the transition period.

14. An assembly, comprising:

at least one processor;

at least one video display configured to be controlled by the processor; and

at least one computer memory with instructions executable by the at least one processor to:

receive a command to change presentation of video from a first content to a second content;

responsive to the content change command, present video on the display using a continuously variable brightness during a transition period, wherein the instructions are executable to present only the second content during the transition period and to change presentation from the first content to the second content at the start time of the transition period.

15. The assembly of claim 9 , wherein the instructions are curable to present both the first content and the second content during the transition period and to change presentation from the first content to the second content during the transition period, between the start time and the end time thereof.

16. A method, comprising:

accessing first and second brightness metadata pertaining to respective first and second contents;

responsive to receiving a command to change presentation from the first content to the second content, establishing a composite brightness using the first and second metadata;

presenting at least one of the contents using the composite brightness at a start time of a transition period;

during the transition period, presenting video using a changing brightness that starts at the composite brightness at the start time of the transition period and ends at the second brightness at an end time of the transition period; and

subsequent to the end time of the transition period, presenting the second content using the second metadata and not using the first metadata.