METHOD AND DEVICE FOR DETERMINING PROPERTIES OF A GRAPHICAL OVERLAY FOR A VIDEO STREAM

• US 20160165271A1
• Filed: 12/03/2015
• Published: 06/09/2016
• Est. Priority Date: 12/04/2014
• Status: Active Grant

• Current Assignee: Axis AB (Canon Inc.)
• Original Assignee: Axis AB (Canon Inc.)
• Inventors: ARDO, Bjorn, Yuan, Song
• Granted Patent: US 10,142,664 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 18/22 Matching criteria, e.g. proximity measures
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: H04N 21/23418 involving operations for analysing video streams, e.g. detecting features or characteristics television picture signal circuitry for scene change detection H04N5/147; filtering for image enhancement G06T5/00; methods or arrangements for recognising scenes G06V20/00; arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/242 Synchronization processes, e.g. processing of PCR [Program Clock References] arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18
• CPC Class Codes: H04N 21/4312 involving specific graphical features, e.g. screen layout, special fonts or colors, blinking icons, highlights or animations
• CPC Class Codes: H04N 21/6125 involving transmission via Internet transmission by internet of broadcast information H04H60/82

Abstract

The present invention relates generally to video communication systems, and more specifically to a method and device for adjusting properties of a graphical overlay for a video stream, the adjusted properties being at least one of a position, a degree of animation and a color composition of the graphical overlay and the adjustment is based on a scene depicted by the time period of the video stream. The adjustment is performed if an estimated bitrate for transmitting an encoded bitstream comprising the time period of the video stream and the graphical overlay exceeds a predetermined upper threshold bitrate for transmitting an encoded single bitstream comprising the time period of the video stream and the graphical overlay.

Claims

1. A method for inserting a graphical overlay on a video stream during a time period of the video stream, comprising:

providing an upper threshold bitrate for transmitting an encoded single bitstream comprising the video stream during the time period of the video stream and the graphical overlay;

calculating an estimated bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay; and

determining if the estimated bitrate exceeds the upper threshold value, and if the estimated bitrate exceeds the upper threshold bitrate;

adjusting at least one of a position, a degree of animation and a color composition of the graphical overlay based on a scene depicted by the video stream during the time period of the video stream such that a bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay at the adjusted position, having the adjusted degree of animation and/or having the adjusted color composition falls below the upper threshold value; and

inserting the graphical overlay on the video stream during the time period of the video stream.

2. The method of claim 1, further comprising:

determining a start frame of the video stream during time period of the video stream by at least one of;

calculating a number of frames since a start frame of a the video stream during a preceding time period of the video stream for which an estimated bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay was calculated and determining if the calculated number of frames is larger than a threshold value;

receiving a pan, tilt and/or zoom signal from a PTZ video camera acquiring the video stream; and

determining a degree of difference between a current frame and a frame of the video stream during a preceding time period of the video stream for which an estimated bitrate for transmitting an encoded bitstream comprising the time period of the video stream and the graphical overlay was calculated by performing a block-matching operation between the current frame and the frame of the video stream during the preceding time period, and determining if the degree of difference is larger than a threshold value.

3. The method of claim 1, further comprising:

encoding the video stream during the time period of the video stream using one or more group of pictures, GOP, structures, each GOP structure comprising an intra frame followed by a plurality of inter frames, wherein a start frame of the video stream during the time period of the video stream coincides with the intra frame of a first GOP structure out of the one or more GOP structures.

4. The method of claim 1, wherein the calculating an estimated bitrate is performed using at least one of:

a required bitrate for transmitting an encoded bitstream comprising the video stream during a preceding time period of the video stream;

a subset of data of the video stream during the time period of the video stream; and

a subset of data of the video stream during a preceding time period of the video stream.

5. The method of claim 1, wherein the adjusted position for the graphical overlay is one of a plurality of predetermined positions.

6. The method of claim 1, wherein the adjusting comprises:

determining a contrast value for each of a plurality of areas in the scene depicted by the video stream during the time period of the video stream, adjusting the position of the graphical overlay based on the determined contrast values.

7. The method of claim 6, wherein if the contrast value corresponding to the determined position of the graphical overlay is below a threshold value, the adjusting further comprises:

determining a color composition of the area corresponding to the determined position of the graphical overlay; and

adjusting the color composition of the graphical overlay based on the determined color composition of the area such that a contrast value between the graphical overlay and the area is reduced.

8. The method of claim 1, wherein the adjusting further comprises:

determining a color composition for each of a plurality of areas in the scene depicted by the video stream during the time period of the video stream; and

adjusting the position of the graphical overlay by comparing the determined color compositions and a color composition of the graphical overlay.

9. The method of claim 5, wherein the adjusting the position of the graphical overlay is associated with receiving a pan, tilt and/or zoom signal from a PTZ video camera acquiring the video stream.

10. The method of claim 1, wherein the adjusting further comprises:

estimating a degree of motion for the video stream during the time period of the video stream; and

adjusting the degree of animation of the graphical overlay for the video stream during the time period of the video stream by reducing the degree of animation by a value, wherein the value is based on the estimated degree of motion.

11. The method of claim 1, wherein the adjusting further comprises:

determining a color composition of an area corresponding to a present position of the graphical overlay; and

adjusting the color composition of the graphical overlay based on the determined color composition such that a contrast value between the graphical overlay and the area is reduced.

12. An article of manufacture including a computer-readable non-transitory storage medium having instructions stored thereon, execution of which by a computing device causes the computing device to perform operations comprising:

providing an upper threshold bitrate for transmitting an encoded single bitstream comprising the video stream during the time period of the video stream and the graphical overlay;

calculating an estimated bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay; and

determining if the estimated bitrate exceeds the upper threshold value, and if the estimated bitrate exceeds the upper threshold bitrate;

adjusting at least one of a position, a degree of animation and a color composition of the graphical overlay based on a scene depicted by the video stream during the time period of the video stream such that a bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay at the adjusted position, having the adjusted degree of animation and/or having the adjusted color composition falls below the upper threshold value; and

inserting the graphical overlay on the video stream during the time period of the video stream.

13. A video stream processing device comprising:

a memory configured to store an upper threshold bitrate for transmitting an encoded single bitstream comprising a video stream during a time period of a video stream and a graphical overlay;

a bitrate estimating module configured to calculate an estimated bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay;

a graphical overlay handling module configured to determine if the estimated bitrate exceeds the upper threshold value, and if the estimated bitrate exceeds the upper threshold value, to adjust at least one of a position, a degree of animation and a color composition of the graphical overlay based on a scene depicted by the video stream during the time period of the video stream such that a bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay at the adjusted position, having the adjusted degree of animation and/or having the adjusted color composition falls below the upper threshold value; and

a graphical overlay inserting module configured to insert the graphical overlay on the video stream during the time period of the video stream.

14. The video stream processing device of claim 13, being a digital video camera, wherein the video stream during the time period of the video stream is acquired by the digital video camera.

15. A system comprising:

a video stream processing device comprising;

a memory configured to store an upper threshold bitrate for transmitting an encoded single bitstream comprising a video stream during a time period of a video stream and a graphical overlay;

a bitrate estimating module configured to calculate an estimated bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay; and

a graphical overlay handling module configured to determine if the estimated bitrate exceeds the upper threshold value, and if the estimated bitrate exceeds the upper threshold value, to adjust at least one of a position, a degree of animation and a color composition of the graphical overlay based on a scene depicted by the video stream during the time period of the video stream such that a bitrate for transmitting an encoded bitstream comprising the video stream during the time period of the video stream and the graphical overlay at the adjusted position, having the adjusted degree of animation and/or having the adjusted color composition falls below the upper threshold value.