Disclosed is a display apparatus in which each pixel corresponds to at least one light-emitting element. The display apparatus includes a display including a plurality of pixels, a driver configured to drive a plurality of light-emitting elements constituting the plurality of pixels, and a processor configured to control the driver to drive the plurality of light-emitting elements based on a first pulse width modulation signal having a duty corresponding to a grayscale of an input image, and to control the driver to drive light-emitting elements constituting a specific pixel, among the plurality of pixels, using a second PWM signal having a duty corresponding to the grayscale of the input image, wherein a frequency of the first PWM signal is different from a frequency of the second PWM signal.

A method and system for controlling implementation of dynamic content modification. The disclosure provides for using at least one steganographically-encoded timestamp in a media stream transmitted to a media client as a basis to determine a transmission delay for media-stream transmission to the media client, and for providing the determined transmission delay as a basis to facilitate control over whether to have the media client implement dynamic content modification. In addition, the disclosure provides for receiving respectively from each of various media clients a report indicating transmission delay determined for the media client based on such steganographically-encoded timestamp data, and using the transmission delays for the media clients to establish a dynamic-content-modification footprint that could be used to control whether, where, and to what extent dynamic content modification will be applied.

A method and system for using steganographically-encoded time information as a basis to control when a client carries out a content-related action. The client processes for presentation one or more linear media streams, each defining a respective time sequence of frames of media content, and at least one of the streams being steganographically encoded with at least one watermark at a respective time-point within linear media stream, the watermark encoding a timestamp of the respective time-point within the linear media stream according to a server clock. The client extracts the timestamp from the watermark and computes a time offset based on a difference between the extracted timestamp and a current time according to a client clock. And the client uses the computed time offset as a basis to determine when the client should carry out a content-related action in a given one of the one or more linear media streams.

A method and system for using steganographically-encoded time information as a basis to control when a client carries out a content-related action. The client processes for presentation one or more linear media streams, each defining a respective time sequence of frames of media content, and at least one of the streams being steganographically encoded with at least one watermark at a respective time-point within linear media stream, the watermark encoding a timestamp of the respective time-point within the linear media stream according to a server clock. The client extracts the timestamp from the watermark and computes a time offset based on a difference between the extracted timestamp and a current time according to a client clock. And the client uses the computed time offset as a basis to determine when the client should carry out a content-related action in a given one of the one or more linear media streams.

Method, devices, systems and computer program products are described that improve speed and accuracy of watermark detection from multimedia content, and allow faster and better content recognition. One technique for improving detection of boundaries of an embedded multimedia content segment includes detecting a synchronization header and a full watermark from the multimedia content, constructing a predicted watermark segment that is positioned at a predicted distance from the synchronization header, and comparing the group of candidate watermark symbols obtained from the multimedia content to the first predicted watermark segment to obtain a match. The disclosed techniques enable extraction of watermarks from short content segments, and can utilize a shortened payload design to establish media time during content usage.

An example symbol-based watermark detection method disclosed herein includes, in response to a comparison of a first count of occurrences of a first potential symbol value corresponding to a first symbol within a watermark and a second count of occurrences of a second potential symbol value corresponding to the first symbol, (i) determining a first accumulated signal to noise ratio value corresponding to the occurrences of the first potential symbol value, (ii) determining a second accumulated signal to noise ratio value corresponding to the occurrences of the second potential symbol value, and (iii) selecting one of the first or the second potential symbol value having a greatest accumulated signal to noise ratio value as a likely symbol value for the first symbol. The example method also includes concatenating the likely symbol value with other likely symbol values corresponding to other symbols of the watermark to detect the watermark.

Provided in the embodiments of the present application are a video watermark generation method and device, and a terminal, the method comprising: determining spatial-domain watermarks and time-domain values corresponding to each video image frame in a video file according to a preset spatial-domain watermark template and a time-domain watermark template, each spatial-domain watermark having the same number of pixel values; determining the edge distribution of each video image frame in the video file; and generating a watermark for the video file according to the spatial-domain watermarks and time-domain values which correspond to the each video image frame and the edge distribution of the each video image frame. The watermark generated by using the video watermark generation solution provided by the embodiments of the present application is better concealed and will not be easily discovered by malicious parties.

Methods and systems for identifying altered content are described herein. The system generates a fingerprint for an unverified content item and locates a plurality of content items that match the fingerprint. The system then compares corresponding frames between the unverified content item and each content item of the plurality of content items. The system identifies, based on the comparing, an altered frame in the unverified content item that does not match a corresponding frame in two or more of the plurality of content items. The system also determines that one or more frames of the unverified content item that follow the altered frame match corresponding frames in the two or more of the plurality of content items. The system then generates for display an indication that the unverified content item contains one or more altered frames.

Angiographic data is obtained by injecting a chemical contrast agent intravascularly, and imaging passage of the contrast as a function of time, thereby generating a sequence of images. To correct error from uncalibrated timestamps embedded in the image metadata, radio-opaque markers are used to generate a watermark embedding timestamp data in obtained images. The radio-opaque markers cause opacification on the x-ray images in the form of dynamic watermarks that encode timestamps. The positions of the markers in the watermark (cast from the radio-opaque markers) are then processed and analyzed to generate an accurate timestamp for the image. By generating an accurate timestamp, synchronized calculations of the images with other data sources are provided.

A computer system for the creation of subliminal image or watermarks where the apparent video is an obvious image and a subliminal or clandestine image or watermark is hidden within the data structure. The concept is envisioned for the cloaking of images, sound, video or like digitized non-coded information. The cloaked files may be intended for storage, transmission, or clandestine placement in a public file system. The watermark may be used for the subliminal marking of a source of a file, its creation, or for tagging copyrighted information.