Wednesday, 25 May 2016

Lossless concatenation of MP4 video files



Source: http://stackoverflow.com/questions/7333232/concatenate-two-mp4-files-using-ffmpeg


ffmpeg -i myfile1.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts int1.ts
ffmpeg -i myfile2.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts int2.ts
ffmpeg -i "concat:int1.ts|int2.ts" -c copy -bsf:a aac_adtstoasc output.mp4
 

Monday, 23 May 2016

RIP - QY8 Bluetooth Earpiece

Purchased: Sep 2015

From: GearBest

Died: May 2016

Issue: No audio in right earpiece. Suspect break in connecting wire between the two earpieces.


While it lasted: Good reception, audio and battery life. Comfortable wear (not too heavy). A little disappointed with the durability because I have always handled it gently.

Tuesday, 22 December 2015

WhatsApp: How to get out of Google Drive backup during restore

Let's say you have accidentally enabled Google Drive backup on your WhatsApp. Now when you want to restore it to a new phone, you find that you have to download 500MB worth of data and wait for an insane amount of time because you don't have fast broadband. What do you do?

I found myself in this situation recently and cracked my head a bit trying to solve it. Thought I'd log this down and save someone else in the same situation a little time.

Firstly, whether or not Google Drive backup is enabled, a local backup file is always created in the SD-card under /WhatsApp/Databases/msgstore.db.crypt8. The full path is typically /storage/emulated/0/WhatsApp/Databases/msgstore.db.crypt8. You have to copy msgstore.db.crypt8 to the the same path on the new smartphone (create the necessary subfolders along the way) before WhatsApp is installed.

The next step delinks WhatsApp from Google Drive so that when you install and run it on the new smartphone, it will not insist on restoring from Google Drive.

From a web browser, login to Google Drive. On the top-right corner, click on the gear icon, then click on "Settings":


 A new popup window will appear.  Select "Manage Apps" on the left.



You should see "WhatsApp Messenger" in the list. Click on "Options, Disconnect from Drive".

You will be given a choice to "Delete hidden app data" in a checkbox. If you leave that unchecked, you can always delete the data later from the "Options" button again.

Once you have disconnected WhatsApp from Google Drive, you can go ahead and install WhatsApp on your new smartphone. When you run it for the first time, it will now search within the local storage for the backup and find msgstore.db.crypt8 if the file is in the right place.

Monday, 26 October 2015

Removing "Whats New" app from Sony Xperia Android smartphones

Sony Xperia smartphones come with a number of Sony crapware, one of which is the "What's New" app that runs in the background and popup from time-to-time as a notification, which is just plain annoying for some of us. Worse, unlike the other crapware, this one cannot be disabled in "App Info" (the "Disable" button is greyed out).

After some research, I found a way to disable this app. First you need to have a working ADB in your system. The trickiest part is to install the correct ADB driver. I referred to this post for help. On my Win7 x64 system, the AdbDriverInstaller method worked for me.

If you don't have adb.exe yet, you need to get it into your system. The official way is to install the Android Platform SDK, but a minimal install of ADB can be found here.

Anyway, to verify that ADB is working properly (both EXE and driver), at the command prompt (with the device connected to the PC via USB cable), type:

adb devices

This should display something like:

List of devices attached
YT91152XZY      device


i.e. there must be at least one device attached.

So much for the prerequisite. The rest is simple. Simply execute the following commands:

adb shell
pm hide com.sonymobile.entrance
exit

That's it!

Older posts on the web recommends pm block com.sonymobile.advancedwidget.entrance, which does not work anymore. So this is a note to myself (and others) to hopefully save some time in case I reset the phone and need to perform this step again in the future.


Monday, 1 June 2015

"System repair disc could not be created. The parameter is incorrect. (0x80070057)"

The simple answer to this error is I was using a CD-R disc instead of a DVD-R disc.

I got stuck for almost 30 minutes googling around and trying out all kinds of suggestions. Then after downloading ISO image and trying to burn it to the disc using ImgBurn, I got an error message in human language telling me the disc has incorrect format. Could be better, but I got the hint.

Developers, we need error messages that a human being of average intelligence can understand.

Sunday, 26 April 2015

Cleaning Roomba's front wheel

You learn something new everyday.

I have been using the Roomba for the past 5 years at least without realizing that the front wheel needed cleaning. I clean the side wheels and the brushes religiously, occasionally using the air compressor, but front wheel, nah.

That's until one of the Roombas started making a funny noise. When it runs, it would sound like it's going over a hump every second. I have heard that before when the bottom brushes are not properly fitted, but this time the problem is not that.

I finally traced it down to the front wheel. I noticed it does have quite a bit of hair stuck in the axle. After struggling on my own for awhile to figure out how to clean the damn thing properly, I turned to YouTube:

 

Turned out it was pretty easy. You just pull the wheel carrier right off with a bit of force, then pop the wheel off with a flat blade screwdriver. Then I found the culprit:


It's a tiny bead from my daughter's DIY necklace toy set, stuck right between the wheel and the carrier. Problem solved.

Of course, pull all that hair and debris off the front wheel axle makes for much cleaner operation overall. So one more thing to add to the Roomba cleaning checklist!