Hardwork always pays off, whatever you do.
本文主要记录笔者在 Gentoo Linux 下面搭建 WebRTC 开发环境的过程。 准备工作 网络：可以科学上网的梯子 IDE：VSCode 或者 CLion 安装depot_tools Google 有自己
概况 WebRTC提供了视频自适应机制，其目的主要是通过降低编码的视频的质量来减少带宽和 CPU 消耗。 视频自适应发生的情形：带宽或 CPU 资源发出信号表明
整体概况 Link：Modeling the Perceptual Quality for Viewport-Adaptive Omnidirectional Video Streaming Considering Dynamic Quality Boundary Artifact Level：IEEE TCSVT 2021 DQB: Dynamic Quality Boundary，指在基于分块的 FoV 自适应全景视频推
Overview Link: Toward Immersive Experience: Evaluation for Interactive Network Services
Level: IEEE Network 2022
Keywords: QoE Metrics
Background Compared with traditional QoE for regular video/audio services, the existing work on IE is still in its infancy. This work aims at providing systematic and comprehensive research on IE for interactive network services, mainly studying the following three fundamental and challenging issues.
What is the essential difference between IE and traditional QoE? Which categories of factors mainly influence IE?
Overview MLflow是一个用于管理机器学习全生命周期的框架。 其主要的作用是： 完成训练和测试过程中不同超参数的结果的记录、对比和可视化——MLflo
Context Create an HTML5 canvas Get the canvas id Obtain WebGL Context The parameter WebGLContextAttributes is not mandatory. Attributes Description Default value alpha true: provide an alpha buffer to the canvas; true depth true: drawing buffer contains a depth buffer of at least 16 bits; true stencil true: drawing buffer contains a stencil buffer of at least 8 bits; false antialias true: drawing buffer performs anti-aliasing true premultipliedAlpha true: drawing
Structure of WebGL Application WebGL application code is a combination of JavaScript and OpenGL Shader Language. JavaScript is required to communicate with the CPU. OpenGL Shader Language is required to communicate with the GPU. Samples 2D coordinates 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
Overview JavaScript JavaScript is used to write the control code of the program, which includes the following actions: Initialization: initialize WebGL context. Arrays: create arrays to hold the data of the geometry. Buffer objects: create buffer objects by passing the arrays as parameters. Shaders: create, compile and link the shaders. Attributes: create attributes, enable them and associate them with buffer objects. Uniforms: associate the uniforms. Transformation matrix: create transformation matrix.
Coordinate System There are x, y, z axes in WebGL, where the z axis signifies depth. The coordinates in WebGL are restricted to (1, 1, 1) and (-1, -1, -1). Positive value meaning: z: near viewer. x: near right. y: near top. Graphics System Vertices To draw a polygon, we need to mark the points on the plane and join them to form a desired polygon. A vertex is a
Bitrate Adaptation Schemes Client-based Recently, most of the proposed bitrate adaptation schemes reside at the client side, according to the specifications in the DASH standard.
Purposes:
Minimal rebuffering events when the playback buffer depletes. Minimal startup delay especially in case of live video streaming. A high overall playback bitrate level with respect to network resources. Minimal video quality oscillations, which occur due to frequent switching. Available bandwidth-based The client makes its representation decisions based on the measured available network bandwidth, which is usually calculated as the size of the fetched segment(s) divided by the transfer time.
