Method and apparatus for establishing an accurate low bit time stamp in a remotely created watermark
View Patent ↗A method and apparatus for placing a time stamp in a remotely applied watermark is disclosed. The method permits a time stamp of high resolution to be added remotely while minimizing the number of bits necessary in the time stamp.
1. A method for time stamping a retrieved version of a media program, comprising the steps of:
receiving a media program in a receiver remote from a headend, the media program having a first watermark including a time stamp describing a media program temporal datum to a first temporal resolution;
storing the media program;
retrieving the stored media program;
reading the first time stamp of the first watermark of the retrieved media program;
computing a second time stamp from the temporal difference between a time at which the media program is retrieved from storage and the media program temporal datum, the second time stamp having a second temporal resolution greater than the first temporal resolution;
generating a second watermark having the second time stamp;
embedding the second watermark in the retrieved media program; and
providing the media program and the embedded second watermark to a device external to the receiver.
2. The method of claim 1 , wherein the second watermark further comprises a receiver unique identifier, and the method further comprises the steps of:
recovering the second watermark from the media program;
determining the second time stamp;
identifying the receiver from the receiver unique identifier, the second time stamp, and the media program temporal datum.
3. The method of claim 1 , wherein the media program temporal datum describes the time the media program was first available for reception and download.
4. The method of claim 3 , wherein the time the media program was first available for reception and download is described with respect to a global temporal datum.
5. The method of claim 4 , wherein the first time stamp includes a count of n time periods after the global temporal datum.
6. The method of claim 4 , wherein the second time stamp comprises at least k bits wherein:
k
=
int
[
log
(
T
theatrical
R
)
log
(
2
)
]
+
1
wherein T theatrical is a theatrical release period of the media program and R is the second temporal resolution.
7. The method of claim 4 , wherein the second time stamp includes a count of m time periods after the first time stamp.
8. An apparatus for time stamping a retrieved version of a media program, comprising:
means for receiving a media program in a receiver remote from a headend, the media program having a first watermark including a time stamp describing a media program temporal datum to a first temporal resolution;
means for storing the media program;
means for retrieving the stored media program;
means for reading the first time stamp of the first watermark of the retrieved media program;
means for computing a second time stamp from the temporal difference between a time at which the media program is retrieved from storage and the media program temporal datum, the second time stamp having a second temporal resolution greater than the first temporal resolution;
means for generating a second watermark having the second time stamp;
means for embedding the second watermark in the retrieved media program; and
means for providing the media program and the embedded second watermark to a device external to the receiver.
9. The apparatus of claim 8 , wherein the second watermark further comprises a receiver unique identifier, and the apparatus further comprises:
means for recovering the second watermark from the media program;
means for determining the second time stamp; and
means for identifying the receiver from the receiver unique identifier, the second time stamp, and the media program temporal datum.
10. The apparatus of claim 8 , wherein the media program temporal datum describes the time the media program was first available for reception and download.
11. The apparatus of claim 10 , wherein the time the media program was first available for reception and download is described with respect to a global temporal datum.
12. The apparatus of claim 11 , wherein the first time stamp includes a count of n time periods after the global temporal datum.
13. The apparatus of claim 12 , wherein the second time stamp comprises at least k bits wherein:
k
=
int
[
log
(
T
theatrical
R
)
log
(
2
)
]
+
1
wherein T theatrical is a theatrical release period of the media program and R is the second temporal resolution.
14. The apparatus of claim 12 , wherein the second time stamp includes a count of m time periods after the first time stamp.
15. A system for time stamping a retrieved version of a media program, comprising:
a receiver, comprising:
a tuner for receiving a media program in a receiver remote from a headend disposed remotely from the receiver, the media program having a first watermark including a time stamp describing a media program temporal datum to a first temporal resolution;
a video storage device for storing the media program in the receiver and for retrieving the stored media program;
a watermark module, for reading the first time stamp of the first watermark of the retrieved media program, for computing a second time stamp from the temporal difference between a time that the stored media program is retrieved from storage and the media program temporal datum, the second time stamp having a second temporal resolution greater than the first temporal resolution, for generating a second watermark having the second time stamp, and for embedding the second watermark in the retrieved media program; and
means for providing the media program and the embedded second watermark to a device external to the receiver.
16. The system of claim 15 , wherein the second watermark further comprises a receiver unique identifier, and the system further comprises:
a watermark analysis module for determining the receiver providing the media program, the watermark analysis module comprising:
a first module for recovering the second watermark from the media program;
a second module for determining the second time stamp; and
a third module for identifying the receiver from the receiver unique identifier, the second time stamp, and the media program temporal datum.
17. The system of claim 15 , wherein the media program temporal datum describes the time the media program was first available for reception and download.
18. The system of claim 17 , wherein the time the media program was first available for reception and download is described with respect to a global temporal datum.
19. The system of claim 18 , wherein the first time stamp includes a count of n time periods after the global temporal datum.
20. The system of claim 19 , wherein the second time stamp comprises at least k bits wherein:
k
=
int
[
log
(
T
theatrical
R
)
log
(
2
)
]
+
1
wherein T theatrical is a theatrical release period of the media program and R is the second temporal resolution.
21. The system of claim 19 , wherein the second time stamp includes a count of m time periods after the first time stamp.