#第六届英特尔杯全国大学生软件创新大赛博客征集#
Video 和 Audio API
概述
¦视频容器和编解码器
音频文件和视频文件其实都是一个容器文件。视频容器包含音频轨道、视频轨道和一些元数据,播放时,音频轨道和视频轨道绑定在一起,元数据指视频的封面、标题、字幕等信息。

#第六届英特尔杯全国大学生软件创新大赛博客征集#
Video 和 Audio API
¦视频容器和编解码器
音频文件和视频文件其实都是一个容器文件。视频容器包含音频轨道、视频轨道和一些元数据,播放时,音频轨道和视频轨道绑定在一起,元数据指视频的封面、标题、字幕等信息。

在上一篇“HTML5标准与性能之一:WebWorkers”中,我们了解了Web Workers为计算密集型的Web应用带来的优势。那这篇文章就为大家介绍另一个有助于性能提升的HTML5标准——Typed Array。
在JS语言中,数值只有一种称为Number的类型,而不像C语言或底层CPU指令那样区分是整型还是浮点型,是有符号的还是无符号的,是32位的还是64位的,因此如果用JS来实现32位整型的除法计算(结果仍是32位整型),就需要利用标准库函数Math.floor (x / y)来模拟实现,可想而知性能会大打折扣。另外,JS不具备二进制格式数据的解析能力,必须利用一些非常规手段来实现,首先要把二进制数据作为文本读入(通过AJAX等),然后用String.prototype.charCodeAt(i)来依次读取每个字节的数据,如果进一步需要解析各种不同类型的数据则难上加难。
One of the pitfalls of parallel programming is the need to consider whether your code modifies a memory location in two parallel strands. Doing so is called a race because whether you get the correct answer depends on the timing of the executed instructions. Parallel reads are OK, since the value doesn’t change. But two writes, or a read and a write in parallel are errors. Consider the following code which increments a global location:
So one of the first questions raised by application developers, is typically how can I get started with app development on Ultrabook™ - well here are some excellent pointers.
Intel® Advisor XE, Intel® VTune™ Amplifier XE, and Intel® Inspector XE all use system GTK* fonts for drawing. They need a vector (scalable) font installed as a default font for the user to show text in different sizes: bigger for titles, smaller for tables and text.
However, you may want to change the font or text size for preference or accessibility reasons. We do not recommend changing the system fonts, obviously, and they are easy enough to override with user-defined fonts stored separately for each user.
使用HTML5开发的应用越来越多,很多针对性能提升的新标准也开始逐渐提出,提交到HTML5、EcmaScript等标准中,给HTML5的应用更强大的计算能力。我们分4篇文章分别介绍一下这些针对HTML5性能的新标准:Web Workers, Typed Array, ParallelArray 和 asm.js。
Web Workers是一个在前端实现多线程的JS接口,属于W3C的HTML5标准的一部分,现在大多数浏览器包括移动浏览器都支持Web Workers.
I will be presenting on May 14th at 11am PDT on the following topic:
Design and prototype scalable threading using Intel® Advisor XE
Please register for this presentation using the following link:
https://www1.gotomeeting.com/register/849275177
Here is a short abstract of the presentation:
Intel® Advisor XE 2013 Update 3 guides developers to add parallelism to their existing C/C++ programs. Using this tool, you can identify where most of the time is spent in your code, which of those locations can actually scale to multi-core and what correctness issues are lurking in those locations. The information provided by this tool can help you decide where to thread your code more judiciously. You can learn more about this tool at the Intel(R) Advisor XE 2013 home page.
Intel® Advisor XE 2013
Intel® Advisor XE 2013 guides developers to add parallelism to their existing C/C++, Fortran, or C# programs.
New in Update 3!
· Improved assistance window
IDF2013英特尔信息技术峰会 HTML5交流体验专区 讲座视频
本届IDF大会共吸引了近万人前来参观,仅HTML5交流体验专区的参会人数就达3千余人,使HTML5专区成为了整个IDF大会人气最旺、最吸引人的区域。
在为期两天的活动中,共进行了20场技术讲座/讨论和16个精彩演示,为参观者呈现了一场难忘的饕餮大餐!
这里我们汇集了讲座的视频,方便大家复习学习。