摘要:
A multi-layered video encoding method is provided wherein motion estimation is performed by using one of two frames of a lower layer temporally closest to an unsynchronized frame of a current layer as a reference frame. A virtual base layer frame at the same temporal location as that of the unsynchronized frame is generated using a motion vector obtained as a result of the motion estimation and the reference frame. The generated virtual base layer frame is subtracted from the unsynchronized frame to generate a difference, and the difference is encoded.
摘要:
A video coding method and apparatus are provided for improving compression efficiency or video/image quality by selecting a spatial transform method suitable for characteristics of an incoming video/image during video/image compression. The video coding apparatus includes a temporal transform module for removing temporal redundancy in an input frame to generate a residual frame, a wavelet transform module for performing wavelet transform on the residual frame to generate a wavelet coefficient, a Discrete Cosine Transform (DCT) module for performing DCT on the wavelet coefficient of each DCT block to create a DCT coefficient, and a quantization module for quantizing the DCT coefficient.
摘要:
An apparatus and method for improving the compression efficiency of a motion vector by efficiently predicting a motion vector in an enhanced layer from a motion vector in a base layer in a video coding method using a multi-layer structure are provided. The method includes obtaining a motion vector in a mother frame of a base layer that is temporally closest to an unsynchronized frame of a current layer, obtaining a predicted motion vector from the motion vector in the mother frame considering the referencing direction in the mother frame and in the unsynchronized frame and distances between the mother frame and a reference frame and between the unsynchronized frame and a reference frame, generating a residual between the motion vector in the unsynchronized frame and the predicted motion vector, and encoding the motion vector in the mother frame and the residual.
摘要:
A method and apparatus of improving the compression efficiency of a motion vector by efficiently predicting a motion vector in an enhancement layer from a motion vector in a base layer in a video coding method using a multi-layer are provided. The method includes obtaining a motion vector in a base layer frame having a first frame rate from an input frame, obtaining a motion vector in a first enhancement layer frame having a second frame rate from the input frame, the second frame rate being greater than the first frame rate, generating a predicted motion vector by referring to a motion vector for at least one frame among base layer frames present immediately before and after the same temporal position as the first enhancement layer frame if there is no base layer frame at the same temporal position as the first enhancement layer frame, and coding a difference between the motion vector in the first enhancement layer frame and the generated predicted motion vector, and the obtained motion vector in the base layer.
摘要:
A method and apparatus for extracting a higher quality video stream for a given bit-rate by replacing a specific frame by a base layer frame at a predecoder are provided. A predecoding method performed by the predecoder includes selecting a mode by determining frames to be skipped according to a predetermined criterion among frames located at positions where the base layer exists, and extracting a portion of the bitstream according to the selected mode and extraction conditions.
摘要:
A method and apparatus for supporting scalability for motion vectors in scalable video coding are provided. The motion estimation apparatus includes a motion estimation module searching for a variable block size and a motion vector that minimize a cost function for each layer according to predetermined pixel accuracy, a sampling module upsampling an original frame when the pixel accuracy is less than a pixel size, and before searching for a motion vector in a layer having a lower resolution than the original frame downsampling the original frame into the low resolution, a motion residual module calculating a residual between motion vectors found in the respective layers, and a rearrangement module rearranging the residuals between the found motion vectors and the found variable block size information using significance obtained from a searched lower layer. Accordingly, true motion scalability can be achieved to improve adaptability to changing network circumstances.
摘要:
A method and apparatus for scalable encoding providing scalability in an encoder. The scalable video encoding apparatus includes a mode selector that determines a temporal filtering order of a frame and a predetermined time limit as a condition for determining to which frame temporal filtering is to be performed, and a temporal filter which performs motion compensation and temporal filtering, according to the temporal filtering order determined in the mode selector, on frames that satisfy the above-described condition. According to the method and apparatus, since scalability is provided in the encoder, stability in the operation of real-time, bidirectional video streaming applications, such as video conferencing, can be ensured.
摘要:
A scalable video codec includes an encoder that encodes an original moving picture; a rate control unit that allocates an optimal amount of bits for each coding unit based on a bit-rate desired by a user; a pre-decoder that receives a bit-stream and extracts a bit-stream having an appropriate amount of bits; and a decoder that decodes image sequences of the moving picture from the extracted bit-stream, so as to reconstruct the original moving picture. In particular, the present invention focuses on the operation performed in the rate control unit 340. The rate control unit operates a definition step of a bit-rate function available for use in the predecoder, a pre-summation step to thereby obtain the uniform visual quality, an approximation to determine the distortion function, and a normalization step to allow the total allocated bit-rates to be equal to a target bit-rate.
摘要:
A method and apparatus for encoding and decoding a video are provided. The method of encoding the video includes: determining whether a unidirectional motion estimation mode and a bidirectional motion estimation mode are to be used based on a size of a current prediction unit to be encoded, performing the motion estimation and the motion compensation on the current prediction unit according to the determining of whether the unidirectional motion estimation mode and the bidirectional motion estimation mode are to be used, determining an optimum motion estimation mode of the current prediction unit based on an encoding cost of the current prediction unit obtained through the performing of the motion estimation and the motion compensation, and encoding information indicating the determined optimum motion estimation mode based on the size of the current prediction unit.
摘要:
Provided are a method and apparatus for transforming an image, in which an input image is transformed into a frequency domain by selectively using a plurality of frequency transform algorithms according to a frequency characteristic of the input image. The method includes: selecting a frequency transform algorithm to be used for a current block from a plurality of frequency transform algorithms according to a result obtained by transforming frequencies of peripheral blocks adjacent to the current block; and transforming the current block into a frequency domain by using the selected frequency transform algorithm.