摘要:
A transcoder for transcoding digital video signals includes a decoder and an encoder. In the decoder, an end-of-block (EOB) position of an incoming block received by the decoder is determined and a discrete cosine transform (DCT) block type is determined based on the determined EOB position. A reduced number of DCT coefficients is computed in a subsequent inverse DCT computation based on the DCT block type. In the encoder, if the incoming block is intercoded, no DCT coefficients are computed after the EOB of the incoming blocks is performing a DCT. Further, in the encoder when the incoming block is intercoded, an algorithm is applied to predict which DCT coefficients may become zero after a subsequent quantization operation, and only DCT coefficients that may not become zero are computed in performing the DCT.
摘要:
Methods and systems for generating motion vectors for re-encoding video signals are disclosed. The motion vector is determined by the sum of a base motion vector and a delta motion vector. In the case of no frame-skipping, the base motion vector is the incoming motion vector. In the case of frame skipping, the base motion vector is the sum of the motion vectors of the incoming signal since the last re-encoded frame and the current frame. The delta motion vector is optimized by a minimum Sum of the Absolute Difference by searching over a smaller area than if searching for a new motion vector without a delta motion vector. These methods and systems may be used to improve re-encoding digital video signals.
摘要:
A method and apparatus for preprocessing a video signal prior to its being encoded. During preprocessing, features are extracted from the video signal into feature planes which are each adaptively filtered in response to estimations of feature activity. After feature extraction the signal which remains is referred to as a “remaining signal”, which is then noise filtered to remove a substantial portion of the noise. The feature planes and remaining signal are recombined into a preprocessed output signal configured for receipt and processing by a video encoder. A video encoder receiving the preprocessed video signal can generate higher quality and/or lower bit rate encoded video than one receiving the original source video. Preprocessing according to the invention is particularly well suited for use with encoders adapted to remove temporal and/or spatial redundancy, such as those implemented according to the MPEG2/4, or AVC/H.264 standards.
摘要:
A display is able to display 3D content in high resolution 2D by utilizing the many views contained in the 3D data and converting the 3D data into 2D data. In some embodiments, the 3D data is converted using shifts in different views of a pixel. In some embodiments, the 3D is converted using shifts in different views of a local pixel and global pixels as well. Displays implementing the 2D high resolution display in addition to a low resolution 3D display are able to display 3D and 2D data depending on a user's preference.
摘要:
A method of deciding a target bit rate for wavelet-based image encoding based on the wavelet coefficients is described. The target bit rate is used for maintaining a high quality image. A minimum target bit rate and a maximum target bit rate are determined. A pseudo code length corresponding to the minimum target bit rate is calculated. The pseudo code length is calculated as a function of the wavelet coefficients. The corresponding pseudo code length is calculated for the maximum target bit rate. A curve between the pseudo code length and target bit rate is derived. Slope of the curve depends on buffer fullness. Using the curve, for a given pseudo code length, an appropriate target bit rate is derived. The derived target bit rate depends on the image content, and computing resources are able to be optimally used to attain similar quality for each image block of an image.
摘要:
A display is able to display 3D content in high resolution 2D by utilizing the many views contained in the 3D data and converting the 3D data into 2D data. In some embodiments, the 3D data is converted using shifts in different views of a pixel. In some embodiments, the 3D is converted using shifts in different views of a local pixel and global pixels as well. Displays implementing the 2D high resolution display in addition to a low resolution 3D display are able to display 3D and 2D data depending on a user's preference.
摘要:
A method of detecting existence of visually thin lines in images is described herein. The method includes profile generation, profile analysis and deciding the existence of thin lines. The profile generation includes generating a profile in each direction of the input image. Multiple projection lines are projected along the direction and all of the pixel values along the projection lines are added and averaged to obtain a profile. The profile analysis includes determining presence of thin lines in the input image and also noticing if the direction of the thin lines is similar to that of the projection lines. At the third step, according to the analysis made, existence of thin lines in the image is decided.
摘要:
Pixel data is compressed using a combination of variable and fixed quantization for luminance data. The luminance is compared to the result of variable quantization and to the result of the fixed quantization to compute a variable noise and a fixed noise. The result of the variable quantization is selected if the variable noise is less than the fixed noise, otherwise the fixed quantization result is selected if the fixed noise is less than the variable noise. The selected result is transferred to a frame memory. In another aspect of the invention, an intra mode coding decision is forced if the noise corresponding to the selected result exceeds a threshold.
摘要:
In one embodiment, a first DCT block of coefficients is received from a transcoding process. The DCT block is of a first size, such as an 8×8 size, and in a first coding standard, such as MPEG-2. A distribution of zero and non-zero coefficients is then determined from the first DCT block. For example, areas where non-zero coefficients may be determined. This may simplify a corresponding sum of absolute difference (SAD) calculation. The SAD is then calculated for a second DCT block of a second size, such as a 4×4 size block, in a second coding standard, such as AVC. The SAD is determined from the coefficients in the first DCT block. Accordingly, the SAD is determined without performing an inverse DCT on the 8×8 block and then computing the SAD for a 4×4 block. It is then determined if a bypass of a DCT operation for the 4×4 block can be performed based on the SAD computed. For example, the SAD is compared to a threshold to determine if a bypass can be performed. In one example, if the coefficients for each 4×4 block are determined that they may be quantitized to zero, then the DCT may be bypassed. Also, quantitization, inverse quantitization, and inverse DCT steps may also be bypassed.
摘要:
A method of improving performance within video decoders subject to the execution of overlapped motion compensation. The method utilizes a triple-buffering approach to achieve rapid data transfers and to eliminate transfer and decoding delays. Each of the three buffers is sequentially utilized for (i) receipt of decoded macroblock data, (ii) insertion of additional decoded macroblock data from a subsequent decoding stage, and finally (iii) the transfer of the collected macroblock data to a transfer buffer. The method is applicable to a number of multiprocessing decoders, and is especially well suited for MPEG-4 and H.263 multiprocessing decoders.