Video lookings the same on different devices

I am building a mobile app where people share videos (like facebook). On the receiving end (person watching a video), how is the video displayed the same size (aspect ratio, usually taking same size) on every device although

1) The uploader device has probably a different camera 2) Not all devices watching the video are the same

Any explanation how apps like FB or Instagram or etc.. do it?

Thank you

Ubuntu 16.04 LTS using loop devices for mounting USB, other removable media


Forgive me — my Google-foo is horrible today.

I’m a developer working on a system running Android as an embedded environment. We are currently working on both Android 7.1.1 and Android 8.

Our development machines are a mix of 16.04 LTS and 18.04 LTS; actual Android builds are done within a 16.04 Docker container so that actual environments don’t cause differences.

Because of some hardware issues, the 16.04 (used by me) needed to have the system restored. I restored it, and now the 16.04 systems show an annoying symptom that was also appearing on the 18.04 machines.

The problem: USB devices not getting properly flushed.

Something has changed in the handling of USB and other removable media. Where once linux would mount the device directly (Imagine flash drive comes up on Xfce desktop as Transfer; double click, Transfer /media/eric63/Transfer is mounted on /dev/sdb1) now, it mounts through a loop! (double click Transfer icon, a second Transfer icon appears, and /media/eric63/Transfer is mounted on /dev/loop0).

This seems to cause no end of problems, not the least of which is that

  • gparted gets confused about the status of the removable drive
  • Android 7 appears to not like the old behavior at all when flashing a system, even if you wait.
  • sync doesn’t, when it comes to flash drives.

So, some questions:

  1. So, what did I do to my system (alternately, what did linux do to my system)?
  2. How do I switch back to the old behavior?
  3. Why is there the new behavior?

Thanks much!

Mobile application – data synchronization between multiple devices in local network

I want to create an mobile application on Android devices but never done applications like this before.

I have several devices that are connected to the same local network without access to the Internet. I want to make one of this devices as master, other will be slaves. If master write text on screen – slaves get this text instantly on their screen or after clicking “send” button on master device.

I’ve tried to find something on the Internet but didn’t find any clues. Can anyone tell me if there is any way to do that application?

CIS (L1) Ensure ‘Devices: Allowed to format and eject removable media’ is set to ‘Administrators and Interactive Users’

I am implementing CIS on Windows 10 1803 and I cannot work out this control.

Description: This policy setting determines who is allowed to format and eject removable NTFS media. You can use this policy setting to prevent unauthorized users from removing data on one computer to access it on another computer on which they have local administrator privileges. The recommended state for this setting is: Administrators and Interactive Users.

Rationale: Users may be able to move data on removable disks to a different computer where they have administrative privileges. The user could then take ownership of any file, grant themselves full control, and view or modify any file. The fact that most removable storage devices will eject media by pressing a mechanical button diminishes the advantage of this policy setting.

For a start, I have never known anyone not be allowed to eject and format removable media (assuming hard disks, usb drives etc).

But I am even less sure on why the control is asking me to set it to ‘Administrators and Interactive Users’ when the default is just ‘Administrators’.

CSC CIS Windows 1803: The recommended state for this setting is: Administrators and Interactive Users. The default value is Administrators only. Administrators and Interactive Users will be able to format and eject removable NTFS media. It is advisable to set Allowed to format and eject removable media to Administrators. Only administrators will be able to eject NTFS-formatted removable media.

Would this setting also upset software that manages USB devices, such as Checkpoint Removable Media Encryption?

CORS Error showing up on some devices only

My webapp is working fine on all devices, except for the Linux devices and my phone where I use (LineageOS + MicroG). The error that i am getting is:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at (Reason: CORS header ‘Access-Control-Allow-Origin’ missing). 

I don’t really know why is this. On my “Server-Client.asp” file, I’ve got the following line:
Call Response.AddHeader("Access-Control-Allow-Origin", "*")

I am using Jquery, but the error it’s not from there, because Jquery is loading fine. Also I am using asp classic. The rest is done with all HTML, Javascript

I really don’t know what to do, I almost tried everything I have found on the internet.

Virgin air-gapped devices and password management

For password management:

“Practical” means it works in practice, and “secure” means protected against compromise and actually works. How do we get the highest P + S value?

I am convinced that all encryption keys for files, not just certification keys, should be generated by a TRNG, be stored offline in a virgin air-gapped device (you first heard it here: never touched the internet), and the passwords should be stored on the air-gapped device too. Forget trying to remember really good passwords because we cannot do it. For example:

-D('w'!\":4D$  aC!)^x#82z-1&:=7c*$  Ege^)x+_mQN0i:!*515i?zaf 



Now we have a physical security problem, and that is very good because it is a problem I can solve. The threat is not in my hometown, my neighborhood, etc., but rather on the big collection platform called the Internet. It is in Novosibirsk.

I am for writing all passwords down, but the trick is that what I write down is not my password and the method to figure out the real one is easy to remember. Huh? What I remember is what my passwords aren’t, and I use a pepper (but no pepper with keys…). Substitution and transposition, Russian copulation, etc., whose value can be quantified and whose strength still depends on the key–all of which is relatively easy to remember. And then I change the method once in a while. I don’t mind writing my pseudo-passwords on a little piece of paper to be stored in my wallet.

What ends up happening is that I do a lot of pecking at the keyboard, true, but one should, and I get to use really tough passwords–either for use on an air-gapped system or not– that employ all 94 characters, are truly random, and can change often. And I skip password managers, which I regard as dangerous.

Is that the best Security + Practicality solution?

Work at home interent monitoring on personal devices

I am about to start a position in which I have to give consent for monitoring.

They provide a Mac Mini and I provide my own monitor, mouse and internet. (They do not pay for it at all.) And no VPN usage from what I know.

I know everything I do on this Mac can be tracked. But I am wondering what can be tracked by the company for my internet usage for all other devices. Can the company track basic info from what I do on my personal PC, even if the Mac isn’t connected to the internet/not on their network?

Answers I found ranges from it’s illegal so companies won’t do it, to they can track everything you do on your home network at all times.

Developing accessory for iOS devices without MFi Program

I am developing a device that will communicate with an app installed on an iOS device. I have some doubts:

  • If I use an MFi cable, do I need to license my product?

  • To communicate by serial port, is it necessary to license the product?

  • Is there any way to communicate with the USB cable that does not require the license?

  • I have nowhere found the cost to license the product, for both development and manufacturing.

The device will be connected and powered over USB.

Note: A proprietary iOS application will be developed to communicate with the hardware.