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Best approach to real time http streaming to HTML5 video client
... HTML5 client (involves re-encoding, so expect quality loss and needs some CPU-power):
Set up an icecast server (could be on the same machine you web server is on or on the machine that receives the RTSP-stream from the cam)
On the machine receiving the stream from the camera, don't use FFMPEG but...
memory_get_peak_usage() with “real usage”
...
<!-- Print CPU memory and load -->
<?php
$output = shell_exec('free');
$data = substr($output,111,19);
echo $data;
echo file_get_contents('/proc/loadavg');
$load = sys_getloadavg();
$res = implode("",$load);
echo $res;
?>
...
How much faster is C++ than C#?
...ter will be competing with your code for instruction and data cache in the CPU. We know that cache dominates when it comes to performance and native languages like C++ do not have this type of contention, by definition.
a run-time optimizer's time budget is necessarily much more constrained than th...
【BLE技术内幕】BLE技术揭秘 - 创客硬件开发 - 清泛IT论坛，有思想、有深度
...用send_LL(0x53,2402M)（注：2402M为信道频率）。这里还有一个问题，设备B怎么知道这个数据包是发给自己的还是其他人的，为此BLE引入access address概念，用来指明接收者身份，其中，0x8E89BED6这个access address比较特殊，它表示要发给周...
How do browsers pause/change Javascript when tab or window is not active?
...stribution: setInterval vs requestAnimationFrame
Note: This test is quite CPU intensive. requestAnimationFrame is not supported by IE 9- and Opera 12-.
The test logs the actual time it takes for a setInterval and requestAnimationFrame to run in different browsers, and gives you the results in the ...
JSON and XML comparison [closed]
...erformance reports, conducted by the W3C, as efficiency and low memory and CPU footprint, is also a matter for the XML area too: Efficient XML Interchange Evaluation.
Update 2015-03-01
Worth to be noticed in this context, as HTTP overhead was raised as an issue: the IANA has registered the EXI enc...
Bash tool to get nth line from a file
...huge, you'd better exit after reading the required line. This way you save CPU time See time comparison at the end of the answer.
awk 'NR == num_line {print; exit}' file
If you want to give the line number from a bash variable you can use:
awk 'NR == n' n=$num file
awk -v n=$num 'NR == n' file ...
Explain the use of a bit vector for determining if all characters are unique
...cause operations with bits are very low level and can be executed as-is by CPU. BitVector allows writing a little bit less cryptic code instead plus it can store more flags.
For future reference: bit vector is also known as bitSet or bitArray. Here are some links to this data structure for differen...
Lua简明教程 - 脚本技术 - 清泛IT论坛，有思想、有深度
...浮点数会慢（除非大于100,000,000,000,000），或是会有精度问题。你可以以如下的方式表示数字，0x开头的16进制和C是很像的。num = 1024
num = 3.0
num = 3.1416
num = 314.16e-2
num = 0.31416E1
num = 0xff
num = 0x56复制代码
字符串你可以用单引号，也...
Evaluating a mathematical expression in a string
...rbitrary commands
eval("9**9**9**9**9**9**9**9", {'__builtins__': None}) # CPU, memory
Note: even if you use set __builtins__ to None it still might be possible to break out using introspection:
eval('(1).__class__.__bases__[0].__subclasses__()', {'__builtins__': None})
Evaluate arithmetic expr...