Apple Inc.

Munehiro Nakazato

Hao Pan

Krishnakanth Rapaka

Jim Chen Chou

Haitao Guo

Xiaohua Yang

Sorin Constantin Cismas

Ganesh G Yadav

Jiandong Shen

Linfeng Guo

Xuemei Zhang

Yingjun Bai

Wei Li

Ke Chen

Haiyan He

Francesco Iacopino

Ye Cong

Xiang Fu

Xu Zhao

In one implementation, a method of generating a bit stream encoding a video stream is performed by a device including one or more processors and non-transitory memory. The method includes decomposing a video stream into a plurality of frequency band video streams. The method includes determining a target bitrate and determining, for each frequency band video stream, a respective frequency band bit rate based on the target bit rate. The method includes encoding each of the plurality of frequency band video streams at its respective frequency band bit rate and transmitting, over a channel, each encoded frequency band video stream.

Multi-band rate control

In one implementation, a method of encoding an image is performed at a device including one or more processors and non-transitory memory. The method includes determining a category of a spatial portion of an image based on a relation between a plurality of thresholds associated with a plurality of quantization scaling parameters and a bit rate of the spatial portion of the image at the plurality of quantization scaling parameters. The method includes quantizing the spatial portion of the image based on the categorization.

Video encoder with quantization control

In one implementation, a method of encoding an image is performed at a device including one or more processors and non-transitory memory. The method includes receiving a first image comprising a plurality of pixels having a respective plurality of pixel locations and a respective plurality of pixel values. The method includes applying a frequency transform to a first spatial portion of the first image to generate a plurality of first frequency coefficients respectively associated with a plurality of spatial frequencies and applying the frequency transform to a second spatial portion of the first image to generate a plurality of second frequency coefficients respectively associated with the plurality of spatial frequencies. The method includes obtaining a first quantization matrix including, for each of the plurality of spatial frequencies, a respective first quantization parameter, wherein a first quantization parameter associated with a first spatial frequency of the plurality of spatial frequencies has a first ratio with a first quantization parameter associated with a second spatial frequency of the plurality of spatial frequencies, and obtaining a second quantization matrix including, for each of the plurality of spatial frequencies, a respective second quantization parameter, wherein a second quantization parameter associated with the first spatial frequency has a second ratio, different than the first ratio, with a second quantization parameter associated with the second spatial frequency. The method includes quantizing the plurality of first frequency coefficients according to the first quantization matrix to generate a plurality of first quantized frequency coefficients and quantizing the plurality of second frequency coefficients according to the second quantization matrix to generate a plurality of second quantized frequency coefficients. The method includes transmitting the plurality of first quantized frequency coefficients and the plurality of second quantized frequency coefficients.

Techniques are disclosed for coding image data adaptively at different levels of downscaling. Such techniques may involve partitioning input data into pixel blocks for coding and performing content analysis on the pixel blocks. The pixel blocks may be input to block coders that operate at different pixel block sizes, which may code the pixel blocks input to them at their respective sizes. Except when a block coder operates at the partitioning size, block coders that operate at different pixel block sizes may perform downscaling of the pixel blocks to match their size with the block coders' respective coding size. A block decoder may invert the coding operations performed by the block coders, decoding coded image data at respective pixel block sizes, then upscaling decoded image data obtained therefrom to a common pixel block size. Image reconstruction may synthesize a resultant image from the decode pixel block data output by the decoders. Quality enhancements may be added by neural network processing systems that have been trained to other segmented images.

Deep quality enhancement of adaptive downscaled coding for image compression

This disclosure relates to a wide gamut encoder capable of receiving a wide gamut color image in accordance with a wide gamut standard. The encoder can encode one or more wide gamut color image pixel values into portions of narrow gamut encoding elements for transmission to a video encoder. The encoder can implement an advanced extended YCC format that is backward compatible with a P3 color gamut.

Extended YCC format for backward-compatible P3 camera video

Growing community of inventors

San Jose, CA, United States of America

Munehiro Nakazato