Abstract: An apparatus and method are disclosed for transcoding a compressed video stream. In one embodiment, a compressed video stream is decoded. A spatial resolution of the decoded video stream can then be dynamically modified. The video stream with the modified spatial resolution can be re-encoded and transmitted over a network for display on a client device. The spatial resolution can be dynamically modified based on a variety of techniques. For example, a current bitrate and quantization parameters associated with the frames can be used to determine the spatial resolution. Alternatively, the spatial and/or temporal complexity can be used to modify spatial resolution.

Abstract: A video encoder identifies a current smooth region of a current picture in a sequence and performs temporal analysis by determining whether a corresponding region in at least one previous and/or future picture is smooth. Based at least in part on the temporal analysis, the encoder adjusts quantization in the current smooth region. An encoder determines a differential quantization interval for a sequence, the interval comprising an interval number. The interval constrains the encoder to skip differential quantization for at least the interval number of predicted pictures after a predicted differentially quantized picture. An encoder analyzes texture in a current picture and sets a smoothness threshold. The encoder compares texture data with the smoothness threshold and adjusts differential quantization for at least part of the current picture based on a finding of at least one smooth region in the current picture according to the smoothness threshold.

Abstract: An encoder is disclosed that is partitioned into discrete hardware modules. The discrete modules include multiple re-entry and exit points that allow enhanced control by software. The software can control the discrete modules during the encoding process and make adjustments according to CPU bandwidth and/or user requirements allowing for enhanced quality control and seamless hardware/software operations. In one embodiment, a media stream is received into an encoder that includes a pipeline of multiple hardware stages for encoding. An intermediate result is provided from at least one of the hardware stages to an encoding control module that processes the intermediate result to determine configuration instructions for a next hardware stage in the pipeline. Thus, the encoding process can be modified dynamically through hardware and software interactions as the media stream progresses through the pipeline of the encoder.

Abstract: An apparatus and method are disclosed for transcoding a compressed video stream. In one embodiment, a compressed video stream is decoded. A spatial resolution of the decoded video stream can then be dynamically modified. The video stream with the modified spatial resolution can be re-encoded and transmitted over a network for display on a client device. The spatial resolution can be dynamically modified based on a variety of techniques. For example, a current bitrate and quantization parameters associated with the frames can be used to determine the spatial resolution. Alternatively, the spatial and/or temporal complexity can be used to modify spatial resolution.

Abstract: Techniques and tools are described for compensating for rounding when estimating sample-domain distortion in the transform domain. For example, a video encoder estimates pixel-domain distortion in the transform domain for a block of transform coefficients after compensating for rounding in the DC coefficient of the block. In this way, the video encoder improves the accuracy of pixel-domain distortion estimation but retains the computational advantages of performing the estimation in the transform domain. Rounding compensation includes, for example, looking up an index (from a de-quantized transform coefficient) in a rounding offset table to determine a rounding offset, then adjusting the coefficient by the offset. Other techniques and tools described herein are directed to creating rounding offset tables and encoders that make encoding decisions after considering rounding effects that occur after an inverse frequency transform on de-quantized transform coefficient values.

Abstract: Techniques and tools are described for compensating for rounding when estimating sample-domain distortion in the transform domain. For example, a video encoder estimates pixel-domain distortion in the transform domain for a block of transform coefficients after compensating for rounding in the DC coefficient of the block. In this way, the video encoder improves the accuracy of pixel-domain distortion estimation but retains the computational advantages of performing the estimation in the transform domain. Rounding compensation includes, for example, looking up an index (from a de-quantized transform coefficient) in a rounding offset table to determine a rounding offset, then adjusting the coefficient by the offset. Other techniques and tools described herein are directed to creating rounding offset tables and encoders that make encoding decisions after considering rounding effects that occur after an inverse frequency transform on de-quantized transform coefficient values.

Abstract: An encoder is disclosed that is partitioned into discrete hardware modules. The discrete modules include multiple re-entry and exit points that allow enhanced control by software. The software can control the discrete modules during the encoding process and make adjustments according to CPU bandwidth and/or user requirements allowing for enhanced quality control and seamless hardware/software operations. In one embodiment, a media stream is received into an encoder that includes a pipeline of multiple hardware stages for encoding. An intermediate result is provided from at least one of the hardware stages to an encoding control module that processes the intermediate result to determine configuration instructions for a next hardware stage in the pipeline. Thus, the encoding process can be modified dynamically through hardware and software interactions as the media stream progresses through the pipeline of the encoder.