摘要:
Image frames of a video stream are encoded with the aim of reducing flicker in the video stream when displayed. In one embodiment, the quantization parameter used to quantize an image frame is capped to be not greater than a quantization parameter used to quantize an immediately previous image frame. In another embodiment, the quantization step size used to quantize a macro-block of an image frame is computed based on the value of a quantization error of a co-located macro-block in an immediately previous image frame. In yet another embodiment, macro-block transform coefficients corresponding to high-frequency components are quantized using relatively higher quantization parameter values if the image frame is deemed to contain high activity. In yet another embodiment, flicker-prone macro-blocks of a source frame are replaced by corresponding best-match macro-blocks of a previous reconstructed frame, prior to being encoded.
摘要:
Image frames of a video stream are encoded with the aim of reducing flicker in the video stream when displayed. In one embodiment, the quantization parameter used to quantize an image frame is capped to be not greater than a quantization parameter used to quantize an immediately previous image frame. In another embodiment, the quantization step size used to quantize a macro-block of an image frame is computed based on the value of a quantization error of a co-located macro-block in an immediately previous image frame. In yet another embodiment, macro-block transform coefficients corresponding to high-frequency components are quantized using relatively higher quantization parameter values if the image frame is deemed to contain high activity. In yet another embodiment, flicker-prone macro-blocks of a source frame are replaced by corresponding best-match macro-blocks of a previous reconstructed frame, prior to being encoded.
摘要:
The method, system, and apparatus of linear temporal reference scheme having non-reference predictive frames is disclosed. In one embodiment, a method of a temporal reference scheme includes creating a non-reference predictive frame and a reference predictive frame from a reference frame, increasing a quantization factor of the non-reference predictive frame by a threshold value, and decreasing the quantization factor of the reference predictive frame by the threshold value. The method may include toggling between the temporal reference scheme and another temporal reference scheme in which there may be no non-reference predictive frames and only reference predictive frames based on a scenario. The method may also include calculating a target bit rate across a communication channel through a bit rate calculation algorithm that considers a bandwidth capacity across the communication channel.
摘要:
This invention predicts that intra mode prediction is more effective for the macroblocks where motion estimation in inter mode prediction fails. This failure is indicated by a large value of the inter mode SAD. This invention performs intra mode prediction for only macro blocks have larger inter mode SADs. The definition of a large inter mode SAD differs for different content. This invention compares the inter mode SAD of a current macroblock with an adaptive threshold. This adaptive threshold depends on the average and variance of the SADs of the previous predicted frame. An adaptive threshold is calculated for each new predictive frame.
摘要:
A video encoder receives a macro-block of an image frame, and determines whether the macro-block contains text. The video encoder computes a quantization parameter for quantizing the macro-block, with the quantization parameter computed to be smaller if the macro-block is determined to contain text. The video encoder encodes the macro-block using the quantization parameter. Text quality in the encoded macro-block is preserved.
摘要:
This invention predicts that intra mode prediction is more effective for the macro blocks where motion estimation in inter mode prediction fails. This failure is indicated by a large value of the inter mode SAD. This invention performs intra mode prediction for only macro blocks have larger inter mode SADs. The definition of a large inter mode SAD differs for different content. This invention compares the inter mode SAD of a current macroblock with an adaptive threshold. This adaptive threshold depends on the average and variance of the SADs of the previous predicted frame. An adaptive threshold is calculated for each new predictive frame.
摘要:
A method of rate control in coding of a video sequence to generate a compressed bit stream is provided that includes computing a sequence base quantization step size for a sequence of pictures in the video sequence, computing a picture base quantization step size for a picture in the sequence of pictures based on the sequence base quantization step size, a type of the picture, and a level of the picture in a rate control hierarchy, and coding the picture using the picture base quantization step size to generate a portion of the compressed bit stream.
摘要:
A video encoder receives a macro-block of an image frame, and determines whether the macro-block contains text. The video encoder computes a quantization parameter for quantizing the macro-block, with the quantization parameter computed to be smaller if the macro-block is determined to contain text. The video encoder encodes the macro-block using the quantization parameter. Text quality in the encoded macro-block is preserved.
摘要:
A method of assigning a priority for controlling a bit rate of a bitstream having a plurality of quality layers is provided. The method includes composing first quality layers for a reference picture, composing second quality layers for a current picture that is encoded with reference to the reference picture, and assigning a priority each of the first and second quality layers, wherein a low priority is assigned to a quality layer having a small influence on a video quality reduction of the current picture when the quality layer is truncated.
摘要:
A color space scalable video coding and decoding method and an apparatus for the same are disclosed that can adjust color components or color depth according to the performance of a decoder side. The color space scalable video coding method includes generating transform coefficients by removing the temporal redundancy and spatial redundancy of input video frames, quantizing the transform coefficients, generating a bit stream by entropy coding the quantized transform coefficients, and generating a color space scalable bit stream that includes the bit stream and position information of luminance data in the bit stream.