The invention concerns a test stream generator for generating a compressed video stream for testing a video decoder, the generator including: a context-aware pseudo-random generator (202) adapted to generate pseudo-random values of syntax elements based on decoding context data; a decoding process module (206, 206′) adapted to process the syntax element values and to generate the decoding context data and binarization context data; and a binarizer module (204) adapted to encode the syntax element values based on the binarization context data in order to generate the compressed video stream.

The invention concerns a test stream generator for generating a compressed video stream for testing a video decoder, the generator including: a context-aware pseudo-random generator (202) adapted to generate pseudo-random values of syntax elements based on decoding context data; a decoding process module (206, 206′) adapted to process the syntax element values and to generate the decoding context data and binarization context data; and a binarizer module (204) adapted to encode the syntax element values based on the binarization context data in order to generate the compressed video stream.

The present invention relates to a multicast-based content transmitting system and method, and a device and method for estimating high-speed movement. Included are: a content providing device for generating N×M multicast stream channels having different transmission start times and transmission rates, providing N×M multicast stream channel lists, and transmitting content through one channel of N×M multicast stream channels; and a user terminal for selecting one channel of the N×M multicast stream channel lists provided from the content providing device and receiving content through the selected multicast stream channel.

The present invention relates to a multicast-based content transmitting system and method, and a device and method for estimating high-speed movement. Included are: a content providing device for generating N×M multicast stream channels having different transmission start times and transmission rates, providing N×M multicast stream channel lists, and transmitting content through one channel of N×M multicast stream channels; and a user terminal for selecting one channel of the N×M multicast stream channel lists provided from the content providing device and receiving content through the selected multicast stream channel.

A method for detecting a freeze-frame condition comprises receiving a sequence of images from at least one digital device; selectively encoding a first subset of the sequence of images using a first coding scheme that causes an adjustment to an image characteristic of the selected images being encoded; selectively encoding a second subset of the sequence of images using a second coding scheme; storing the first encoded subset and second encoded subset; retrieving the stored first encoded subset and second encoded subset; selectively decoding the first subset of the selected images using the first coding scheme and selectively decoding the second subset of the selected images using the second coding scheme to re-create the sequence of images. A freeze-frame condition in the re-created sequence of images is identifiable based on a plurality of decoded images being different with respect to the image characteristic across multiple decoded image frames.

A method for detecting a freeze-frame condition comprises receiving a sequence of images from at least one digital device; selectively encoding a first subset of the sequence of images using a first coding scheme that causes an adjustment to an image characteristic of the selected images being encoded; selectively encoding a second subset of the sequence of images using a second coding scheme; storing the first encoded subset and second encoded subset; retrieving the stored first encoded subset and second encoded subset; selectively decoding the first subset of the selected images using the first coding scheme and selectively decoding the second subset of the selected images using the second coding scheme to re-create the sequence of images. A freeze-frame condition in the re-created sequence of images is identifiable based on a plurality of decoded images being different with respect to the image characteristic across multiple decoded image frames.

The present application relates to a system for verifying integrity of a stream of image frames including an encoder logic module and a decoder logic module. On source side, a test line insertion logic module receiving the stream is arranged upstream to the encoder logic module encoding the stream. The test line insertion logic module is configured to include one or more test lines into the image frames. A color coding is assigned to the one or more test lines. The color coding is selected from a coding scheme. On destination side, a test line detection and extraction logic module is arranged downstream to the decoder logic module receiving the encoded stream. The test line detection and extraction logic module extracts the color coding from the received image frames and verifies extracted coding data against the coding scheme. The coding data comprises at least the extracted color coding.

An encoded representation of a picture of a video stream is decoded by retrieving buffer description from the encoded representation. The buffer description information is used to determine at least one picture identifier identifying a respective reference picture as decoding reference for the picture. A decoded picture buffer is updated based on the determined picture identifier. The encoded representation of the picture itself comprises the information needed by a decoder to identify the reference pictures required to decode the encoded representation.

An encoded representation of a picture of a video stream is decoded by retrieving buffer description from the encoded representation. The buffer description information is used to determine at least one picture identifier identifying a respective reference picture as decoding reference for the picture. A decoded picture buffer is updated based on the determined picture identifier. The encoded representation of the picture itself comprises the information needed by a decoder to identify the reference pictures required to decode the encoded representation.

Utilizing two LTR frames for improved error recovery. By using two LTR frames, much better performance is achieved in terms of error recovery as the likelihood of the decoder having one of the two LTR frames is very high. When the decoder determines a frame is lost, the decoder provides a fast update request (FUR). The FUR includes a listing of the LTR frames present at the decoder. With this indication of the LTR frames present at the decoder, the encoder utilizes one of the LTR frames, preferably the most recent, to use as a reference to send the next frame as a P frame. The P frame is sent with an indication of the LTR frame used as reference. The use of two LTR frames and the feedback of LTR frames present at the decoder allows the minimization of the use of I frames for error recovery.