Ati Technologies Ulc

Advanced Micro Devices Corporation

Edward A Harold

Gabor Sines

Ihab Amer

Lei Zhang

Haibo Liu

Ying Luo

Yang Liu

Wei Gao

Feng Pan

Khaled Mammou

Crystal Yeong-Pian Sau

Jiao Wang

Fabio Gulino

Shu-Hsien Wu

Ihab M A Amer

Ho Hin Lau

Ehsan Mirhadi

Boris Ivanovic

Andy Sung

Richard E George

Jinbo Qiu

Benedict Chien

Zhiqi Hao

Samuel D Naffziger

Zhen Biao Chen

Ahmed M Abdelkhalek

Baochun Li

Crystal Sau

Zhong Hai Cai

Zhenhua Yang

Stephen Ho

Razvan Florin Dan-Dobre

Catalin Beju

Zohair Sahraoui

Ying Zhang

Yao Wen Yu

Dennis Lew

Mehdi Semsarzadeh

Min Wang

Alvin Duong

Kai Sun

Lawrence A Bair

Steven Lok-Man Doo

Jonathon Walter Riley

John-Paul A Compagnone

Gerald S C Chan

Ihab MA Amer

John-Paul Compagnone

Gerald Sc Chan

Techniques for implementing adaptive interpolation filter search in video encoding are disclosed. Conventional interpolation filter searching is simplified to implement adaptive interpolation filter search by selecting one or more first filter types to determine one or more initial interpolation costs. After identifying an MV that produces a target interpolation error for one of the one or more first filter types, one or more secondary interpolation costs are calculated for one or more additional filter types based on the identified MV, and one of the one or more first filter type and one or more additional filter types that results in minimal interpolation error is selected as the interpolation filter type.

Adaptive interpolation filter search

An encoder implements a residual-free palette encoding mode in which a block of pixels is used to derive a palette table having a number of palette colors less than a number of pixel colors in the block of pixels, and to derive a color map representing each pixel of the block with a corresponding index number associated with a palette color that most closely matches the pixel's color. The calculations of residuals representing errors between the predicted palette colors and the actual pixel colors are omitted during the encoding process, thereby facilitating implementation of less complex palette mode encoder hardware at the expense of slight loss of color accuracy. Moreover, when multiple encoding modes are available, the encoder can employ the residual-free palette encoding mode when the rate-distortion cost or other cost of using this mode is determined to be the lowest cost of the plurality of encoding modes.

Residual-free palatte mode coding

An encoder encodes an image portion by recursively partitioning the portion into a partitioning hierarchy of levels. The top level has a single block representing the entire portion and each lower level has four smaller blocks representing a corresponding larger block at a higher level. A palette table is generated for each bottom-level block based on the pixels of the associated block. For each successively higher level, the encoder generates a palette table for each current-level block by selecting palette colors based on the palette colors from the four palette tables for the associated four blocks at the next-lowest level. A color index map is then generated based on a final palette table selected from the palette tables generated for the partitioning hierarchy. A representation of the portion is then encoded using the final palette table and the color index map to generate a corresponding segment of an encoded bitstream.

Palette mode video encoding utilizing hierarchical palette table generation

Systems, apparatuses, and methods for performing parallel histogram calculation with application to palette table derivation are disclosed. An encoder calculates a first histogram for a first portion of pixel component value bits of a block of pixels. Then, the encoder selects a first number of the highest pixel count bins from the first histogram. Also, the encoder calculates a second histogram for a second portion of pixel component value bits of the block. The encoder selects a second number of the highest pixel count bins from the second histogram. A third histogram is calculated from the concatenation of bits assigned to the first and second number of bins, and the highest pixel count bins are selected from the third histogram. A palette table is derived based on these highest pixel count bins selected from the third histogram, and the block of pixels is encoded using the palette table.

Parallel histogram calculation with application to palette table derivation

Systems, apparatuses, and methods for calculating multi-pass histograms for palette table derivation are disclosed. An encoder calculates a first histogram for a first portion of most significant bits (MSBs) of pixel component values of a block of an image or video frame. Then, the encoder selects a given number of the highest pixel count bins from the first histogram. The encoder then increases the granularity of these selected highest pixel count bins by evaluating one or more additional bits from the pixel component values. A second histogram is calculated for the concatenation of the original first portion MSBs from the highest pixel count bins and the one or more additional bits, and the highest pixel count bins are selected from the second histogram. A palette table is derived based on these highest pixel count bins selected from the second histogram, and the block is encoded using the palette table.

Hierarchical histogram calculation with application to palette table derivation

Still frame detection for single pass video data, including: determining that an average quantization parameter of a frame of video data falls below a quantization parameter threshold; determining whether an amount of skipped macroblocks in the frame meets a skipped macroblock threshold; and responsive to the amount of skipped macroblocks exceeding the skipped macroblock threshold, identifying the frame as a still frame.

Still frame detection in video data

An encoding method is provided which includes receiving a plurality of images, obtaining values of elements in a portion of the images, sorting the elements according to different values of the elements, sorting the elements according to a number of occurrences of the different values and encoding the elements using a subset of the different values having corresponding numbers of occurrences that are higher than corresponding numbers of occurrences of other values. Examples also include a processing device and method for use with palette mode encoding in which the elements are a portion of pixels in images and the values are color values of the portion of pixels in the images.

Top palette colors selection using sorting for palette mode in video encoding

A technique for determining an adaptive quantization parameter offset for a block of encoded video includes obtaining a rate control factor for the quantization parameter, determining a content-based quantization parameter factor for the quantization parameter, determining an adaptive variance based quantization offset based on content-based quantization parameter factors for a frame prior to the current frame, and combining the rate control factor, the content-based quantization parameter factor, and the adaptive offset to generate the quantization parameter.

Adaptive offset for variance based quantization

Techniques for encoding and decoding media content, and more specifically to selecting filter coefficients for filtering coding artifacts from the encoded media content are described. The filter coefficients are selected by an encoder for a given frame based on a statistical record of one or more previous frames in a data stream. The statistical record indicates the effectiveness of different sets of filter coefficients in reducing encoding artifacts for the one or more previous frames. By employing the statistical record to select filter coefficients for the next frame in the data stream, the encoder is able to select the filter coefficients relatively quickly, reducing encoding latency while ensuring that a decoder is able to effectively decode the encoded frames.

Single pass filter coefficients selection

Systems, apparatuses, and methods for generating a model for determining a quantization strength to use when encoding video frames are disclosed. A pre-encoder performs multiple encoding passes using different quantization strengths on a portion or the entirety of one or more pre-processed video frames. The pre-encoder captures the bit-size of the encoded output for each of the multiple encoding passes. Then, based on the multiple encoding passes, the pre-encoder generates a model for mapping bit-size to quantization strength for encoding video frames or portion(s) thereof. When the encoder begins the final encoding pass for one or more given video frames or any portion(s) thereof, the encoder uses the model to map a preferred bit-size to a given quantization strength. The encoder uses the given quantization strength when encoding the given video frame(s) or frame portion(s) to meet a specified bit-rate for the encoded bitstream.

Content adaptive quantization strength and bitrate modeling

Systems, apparatuses, and methods for reducing latency when consuming an encoded video bitstream in real-time are disclosed. A video encoder encodes a video bitstream and writes chunks of the encoded bitstream to a bitstream buffer. Prior to the encoder completing the encoding of an entire frame, or an entire slice of a frame, a consumer module consumes encoded chunks of the bitstream. In one implementation, to enable pipelining of the consumption with the encoding, the encoder updates a buffer write pointer with an indication of the amount of data that has been written to the bitstream buffer. The consumer module retrieves encoded data from the bitstream buffer up to the location indicated by the buffer write pointer. In this way, the consumer module is able to access and consume encoded video data prior to the encoder finishing encoding an entire frame or an entire slice of the frame.

Low-latency consumption of an encoded video bitstream

Systems, apparatuses, and methods for calculating multi-pass histograms for palette table derivation include an encoder that calculates a first histogram for a first portion of most significant bits (MSBs) of pixel component values of a block of an image or video frame. Then, the encoder selects a given number of the highest pixel count bins from the first histogram. The encoder then increases the granularity of these selected highest pixel count bins by evaluating one or more additional bits from the pixel component values. A second histogram is calculated for the concatenation of the original first portion MSBs from the highest pixel count bins and the one or more additional bits, and the highest pixel count bins are selected from the second histogram. A palette table is derived based on these highest pixel count bins selected from the second histogram, and the block is encoded using the palette table.

Systems, apparatuses, and methods for calculating a quantization parameter (QP) for encoding video frames to meet a given bit budget are disclosed. Control logic coupled to an encoder calculates a complexity indicator that represents a level of difficulty in encoding a previous video frame. The complexity indicator is based at least in part on a first parameter associated with the previous video frame and corresponds to one or more of a variance, an intra-prediction factor, and an inter-to-intra ratio. The complexity indicator is then used by the control logic to calculate a preferred QP to use to encode the current video frame to meet a given bit budget. By using the preferred QP generated based on the complexity indicator, the encoder is able to make fewer QP adjustments during the frame. This helps to improve the visual quality of the resulting encoded video bitstream.

Efficient quantization parameter prediction method for low latency video coding

An encoder encodes pixels representative of a picture in a multimedia stream, generates a first approximate signature based on approximate values of pixels in a reconstructed copy of the picture, and transmits the encoded pixels and the first approximate signature. A decoder receives a first packet including the encoded pixels and the first approximate signature, decodes the encoded pixels, and transmits a first signal in response to comparing the first approximate signature and a second approximate signature generated based on approximate values of the decoded pixels. If a corrupted packet is detected, the multimedia application requests an intra-coded picture in response to the first approximate signature differing from the second approximate signature. The second signal instructs the decoder to bypass requesting an intra-coded picture and to continue decoding received packets in response to the first approximate signature being equal to the second approximate signature.

Method and apparatus for determining the severity of corruption in a picture

Growing community of inventors

Scarborough, Canada

Edward A Harold