Change DPI on Android custom ROMs

Some ROMs like Slim ROM change the DPI setting so that objects on the screen are much smaller than is comfortable for me. This site told me how to change the DPI setting.

We need root access for this. Any file explorer with root access is fine. Root explorer is an excellent paid option, but ES file manager will do just fine as a free app. Follow the steps below.

  1. Navigate to /system
  2. Click on Mount RW (It should appear as Mount RO, that’s when it is correct!)
  3. Look for build.prop. Long press on the file and press Open file in Editor
  4. Scroll down to ro.sf.lcd_density=240
  5. Change the value to anywhere between 180 and 240. The lower the value, the higher density your screen will have.
  6. Click on the Menu button, and Save and Exit.
  7. Reboot.

Extracting audio from video

I had this problem recently. I had downloaded videos from Coursera and I wanted to watch/listen to them on my Ipod Touch. Of course, nothing is straightforward on the idevices. I tend to listen to the lectures in the gym, so mostly listening and not watching. On my Note 2 I can lock the screen so that the video continues playing while I put the phone in my pocket. But the ipod does not. So I needed to extract the audio from the video (fortunately these lectures are not visually intensive).

Handbrake does not do it, and other options I found include installing ffmpeg on the command line using homebrew. Finally someone informed me that I could do this natively in the Mac OS. This page contains the details. The gist is the following:

Encode video service on

Go to ’System Preferences \( \rightarrow \) Keyboard \( \rightarrow \) Shortcuts. Click on Services and ensure that the “Encode selected video files” and “Encode selected audio files” services are selected. This will make these options visible when you right-click on a video file.

Extract audio

Select one or more video files, right-click, Services and select “Encode selected video files”. In the first dropdown at the top, select Audio only. Select where to store the audio files, then encode.

The nice thing about this is that you can batch process.

Disable two-finger scrolling in Chrome

This was a major pain for me. I use two-finger scroll for vertical and horizontal scrolling. Chrome trips me up by occasionally (when I swipe fast enough) browsing through my page history. A big inconvenience especially when one is working on documents or forms online. Almost got to the point where I was thinking of swearing off Chrome altogether.

I looked online and found some forums which said that it couldn’t be done. Then I found this website which gives simple instructions to disable this on an application basis. Just run the following command in terminal:

defaults write AppleEnableSwipeNavigateWithScrolls -bool FALSE

 Update: This doesn’t seem to work in Mavericks. Chrome still has the same annoying behavior.

Aquamacs line wrapping

On and off, Aquamacs starts behaving strangely with the line wrap. I usually have word-wrap mode set. And yet, when I open an org-mode file I see that truncate-mode or some other such is set. Here is what to do to get it back to normal:

Go to Options -> Customize Aquamacs -> Aquamacs-specific options. That will open up a buffer with a bunch of options. Scroll down to ‘Text mode hook’. Unselect all the options, select set-word-wrap and delete all the extra options set at the bottom, if any. Save for all sessions.