Thursday, August 31, 2017

splitting a multi-track wav file into separate channels in Reaper 3.5

Right-click on the track, choose Item processing -> Explode multichannel audio or midi items to new mono items 

Wednesday, May 17, 2017

converting a FAT32 volume to NTFS and backups

With WCry and other malware in the wild, I wanted to take a full system backup of the Acer laptop. Decided to go with Windows built in backup - Start -> Run -> ntbackup

Around half an hour later, ntbackup complained that the drive it was writing to was FAT32, and does not allow files larger than 2 GB (or 4GB? I forgot). Decided to convert it to NTFS, retaining the data on it.

Ran convert from command prompt. It failed, complaining that there was insufficient memory. Moved over the existing files to another hard disk and then tried convert again. It again complained of insufficient memory. Probably a 2 TB volume is too much for it on a 32 bit system. So, Control Panel -> Administrative Tools -> Computer Management -> Disk Management. Deleted the partition, created it again as NTFS.

While formatting the new volume, I wanted to see what would happen if I do not choose Quick Format. Format took 5 hours for the 2 TB drive!

And after that, the backup of C, D and E drives, creating a 239.4 GB single file, took around 12 hours. 

Sunday, May 14, 2017

stopping unwanted notifications on Android

Some apps bring up annoying notifications. Examples - the activation messages for Cloud Messaging on Xiaomi phones, Airtel's and Paytm's "offers" and so on. An easy solution was to pull down the notification bar, click and hold the notification till a box appears with "App Info" - may be seen as an exclamation mark icon. Click on that, which gives an option to block notifications from that app. 

preparing Mandir Live Files for Download

From an email by PA.

Steps to process live files

1. Open finder and click on ‘Mandir Live Recordings’, click date modified

2. The first few files will be that morning's and the previous days

3. Open ‘Magic Cutter’, drag and drop the file with yesterday’s date. Morning file will end with ‘_1’ and evening with ‘_2’

4. Double clicking on the wave will give you the split marker. Place one marker just when ‘Omkar’ of vedam starts and one before ‘Omkar’ of bhajans start. (You will need to connect the earphones to the mac mini's 3.5 jack to hear the file)

5. Then click ‘Split’

6. Now it will ask for where to save. Click the drop down on top of the dialogue box and select the folder ‘Split Files’

7. It will take 2 seconds to complete. Then repeat the same for Evening file.

8. After both files have been split, close Magic Cutter. In the finder go to the folder ‘Split Files’ in the sidebar.

9. Once there, again click date modified. You will see 6 files with names different from the rest. Date followed by ’_01_01’ and so on.

10. Now delete the 2 files that have the announcement. (They will be the 2 files with least size)

11. Now rename the files just like the other files in the folder. Morning vedam and bhajan files should have the date and end with '_AM_VEDAM' and '_AM_BHAJAN' respectively
Evening vedam and bhajan files should end with '_PM_VEDAM' and '_PM_BHAJAN' respectively

12. After renaming, close Finder and open 'Filezilla'

13. In the menu right on top of the monitor, click bookmarks and select the bookmark, 'Split Files'.

14. Once the connection is established, transfer the files that you just renamed. Double-click files one by one, or select, drag & drop.

Friday, April 28, 2017

Blender links

Some Blender links which I found useful:

In this tutorial, there is a mention of how the output may look grainy if the object in blender is not scaled up. But I was not successful in improving my OCT renders though I scaled up the cube 2 or 3 times.

Tuesday, April 25, 2017

installing the latest blender on Linux Mint

I needed to install Blender 2.78 for compatibility with files created on Windows with 2.78. The Linux Mint repository (Ubuntu repository) carried the earlier version of Blender. So, followed this guide to install 2.78.

sudo add-apt-repository ppa:thomas-schiex/blender
sudo apt update 
sudo apt install blender

To go back to the default version, I need to do
sudo apt install ppa-purge 
sudo ppa-purge ppa:thomas-schiex/blender

Wednesday, April 19, 2017

updated live broadcast procedure

My old post on Mandir live broadcast procedure needs an update. A lot of steps have been removed.

  1. Power on procedure is:
    (a) UPS input on
    (b) UPS on
    (c) Tascam US-1641 power on
    (d) Compressor on
    (e) MacMini power on
    Power down procedure follows in the reverse order.
  2. In case they don't start automatically, start Reaper and BuTT. 
  3. The setup can be tested by playing the output of reaper. Reaper channels 1-8 are mapped to sliders 1-8 on the Korg NanoKontrol. Channels 9-14 are mapped to knobs 1-6. Channel 5 is also mapped to slider 9, since slider 5 has some issues.
    Channel 12 (knob 4) has instrumental music and 
    Channel 13 (knob 5) has the pre-live announcement pre-loaded.
    Channel 3 (slider 3) has the full mix output of PA mixer coming in.
    Pressing play on the Korg NanoKontrol allows you to test whether the BUTT gets signal when knob 5 is opened, as seen by the lit up LED-style indicators on BUTT.
  4. Start playback of pre-live Announcement in Reaper approximately 3 minutes before desired start of live broadcast.
  5. Press the 'Play' button in BUTT to start live broadcast on AsiaStream + TeluguStream.
  6. Fade out knob 5 and allow knob 6 to maintain around -12 dB at the output when the program starts. Playback can be stopped with the stop button on the NanoKontrol.
  7. Recording of programs is mapped to Channel 15 which is record enabled. The spacebar is the shortcut key.This recording is not necessary for daily bhajan and vedam - BuTT records those automatically.
  8. If recording is in progress, if a filler instrumental is to be added, BI.mp3 can be dragged from desktop to Channel 12 (knob 4) which has record enable DISABLED - the dull red ar button.
    Unless the track has record enable Disabled, playback will not occur from the track.
  9. The same procedure as above can be used to drag and drop the ANN_END_LIVE end announcement file for playout at the end of special program broadcasts.
  10. The ambient hall mic is connected to the XLR input Channel 8 on the Tascam, and this is opened for bhajan chorus etc.
  11. The live broadcast is stopped by hitting the stop button on BuTT, and answering 'Yes' when asked if the recording can be stopped. 

Sunday, April 09, 2017

enabled showing text for location in Nemo

and enabled textual location address in Nemo file browser, after installing dconf-editor, by checking show-location-entry in org nemo preferences.

Friday, April 07, 2017

removing old kernels

After a kernel update, found on Mint Linux that there were quite a few old kernels present, which must be using up quite a bit of disk space. As suggested by a post at


sudo apt-get install byobu
sudo purge-old-kernels

Seems to have cleared up nearly 700 MB.

Wednesday, April 05, 2017

removing malware/adware from Intex phone - deux

My earlier post about removing adware and malware from the Intex phone was too optimistic. The pop-ups asking to install UC Browser and so on had not stopped. So, I tried to delete files which I thought were causing the issue, by directly deleting files from /System/Apps. But then, when I tried to reboot the phone, it went into a loop, saying "Optimizing apps 1 of 72" or something like that, and would not start. So the phone was soft-bricked.

I thought it would be a good idea to reflash the firmware and use Root Uninstaller or some such tool instead. But after flashing using SP Tool, found that the phone was hard bricked. Hard-bricked meaning that the phone would not charge, would not go into recovery mode if switched on with volume down also.

After initial attempts to get it fixed by the local mobile repair guy - "Please try the Intex service centre" - and service centre - "Please bring the item, we will look at it and then tell you how much it will cost" - explored the ways to get it back to working condition. And found this guide. Warning - that page is not safe to open without an ad-blocker, and perhaps even with an ad-blocker!

So, the basic idea is - install the correct drivers, remove the battery, flash the boot loader first, then flash the rest of the firmware.

As mentioned on that page, the issue seemed to be wrong firmware. I thought I would install the latest firmware by using Intex_Aqua_4G_Strong_V06_Indian_SER_20160408-150449 but apparently my phone only accepts Intex_Aqua_4G_Strong_V03_1_8_Indian_SER_20160622_MT6735M

Another issue was that the driver was not installed properly on my WinXP machine. Installed the VCOM drivers properly on a Win7 machine, and then the firmware update went smoothly. Then uninstalled lots of bloatware, malware and adware, using Root Uninstaller which keeps a backup of the uninstalled apk, rebooting after every doubtful uninstall. Now at last the phone seems to be clean.

Some points which I noted were:

  • Kingroot seems to need a SIM installed in the phone to root.
  • Malwarebytes might be interfering in Kingroot's process, so I uninstalled it before trying to root again.
  • Also, prevented the screen from going to sleep. Not sure if this is important, though. 
  • Unfortunately I did not note down the names of the apps I removed. Everything with Intex in the name, also App Age Helper or something like that, and the three which malwarebytes pointed out. 

Monday, April 03, 2017

pkg install on octave

Octave has many Matlab compatible packages, but they need to be installed and loaded using
pkg Load pkgname
and similarly
pkg unLoad pkgname
This actually adds it to octave's path.

But before that, the packages have to be installed. On my Mint Linux 18 install, had install liboctave-dev first using apt-get and then inside octave,
pkg install -forge -verbose signal
pkg install -forge -verbose control

Saturday, April 01, 2017

line ending issue for Linux bash script - bad interpreter

Faced the issue of

/bin/bash^M: bad interpreter: No such file or directory

on Linux Mint, for a copy-pasted file from Windows. I knew that this was most probably due to a CR-Linefeed issue. The default text editor, xed, did not seem to fix it. Finally, as this page suggested, used
:set ff=unix
in vim and then saved the file with :wq - solved.

Edited: 1st April 2017 - :set ff=dos is for Windows style CR/LF .... 

Thursday, March 30, 2017

octave idiosyncracy

While operating a loop in GNU Octave, I wanted a counter to be displayed. In the script, this needed

before other statements, and in the Octave command window,
more off;
to turn paging off.

Friday, March 17, 2017

dcraw speeds

It would be useful to be able to edit the dcraw code to make it convert only a region of interest - conversion times are quite long.

On Windows 8, running on an i7, 7.8 sec per image for 14 megapixel CR2 file from a Canon 1100D.
On Macbook i7 with Linux Mint 18, 4.4sec
On Windows XP, running on a 1.9 GHz Athlon, 12 sec.

Converted using
dcraw -v -4 -H 0 -W -w -q 3 -T

Sunday, March 12, 2017

removing adware from Intex Aqua 4G Strong mobile phone

The Intex Aqua 4G Strong mobile phone running Android 5.1 which I had purchased to try out Reliance Jio had annoying adware and bloatware in the firmware. I uninstalled as many as I could, but some of them could not be uninstalled. I tried preventing notifications from them by long press on the notification to pull up the app's notification settings, and unchecking notifications from those apps. But still, on every restart, some app would try to install UCNews etc from outside Google Play store, and would be blocked by the security setting to Not Allow Apps from outside the Play store.

Finally thought I should get rid of this malware / adware.

  1. Installed and ran Malwarebytes Anti-Malware app.
  2. It identified the Malware as two apps, with the path to the apks being in the /system/ folder.
  3. Since the apps were masquerading as System apps, they could not be uninstalled except as Root. So, installed Kingroot via the XDA developers forum to root the device. 
  4. Ran Root Checker Basic to check for root - done. 
  5. Installed Root Browser.
  6. When running Root Browser, it asks if it can install some utilities. Said yes, it installed busybox tools. These are necessary to remount the volume as rw, and remove from system folder.
  7. Navigated to /system/apps and removed the folders containing malware.
  8. Ran Malwarebytes again to check that those were removed.
  9. Removed Kingroot through its uninstall option.
  10. Checked that root is now disabled.
  11. Removed Root Checker.
  12. Checked again with Malwarebytes that all is well. Done. 
Edit - this saga continues in another post here

Monday, February 20, 2017

GPT partition - issues with re-partitioning new hard disk

described my issues with partitioning a new hard disk. Solution, as given there, was to use the command prompt,
list disk
select disk

and then initialize the disk with Disk Management. 

Monday, February 13, 2017

configuring a DLink DCS-942L camera

In May, I had struggled with port-forwarding, virtual server on router etc while setting up a DLink DCS-942L home network camera. Now, re-configuring it to use a JioFi 4G router, just had to remove the static ip using the Windows setup wizard, then WPS to connect to the wifi network, and that was it. No manual port-forwarding was needed. 

Thursday, February 09, 2017

some notes on download speeds

There was a planetarium show which was offered for a free download as a single 150 GB file from an FTP server. Some notes on my experience trying to download it.

I tested the download and found that FTP download is limited to 1 Mbps for us per connection over Tata internet 14 Mbps line.

With CuteFTP, max 4 connections = 4 Mbps.

With our server in the US, single connection on 1 Gbps line to backbone, 80 Mbps.

Downloading from our US server to Studio / Planetarium over SFTP - 8 Mbps, maybe will go up to the rated 14 Mbps at night.

So, if similar speeds are experienced, probably the best way would be to download to our US server, and then download to Studio/Planetarium in batches.

Tuesday, February 07, 2017

ode45 on octave

Trying the gnlse numerical solution for SCG from the Dudley book using GNU Octave - the Matlab clone. The Octave "port" needed some modifications.

  1. The report function doesn't work properly, so probably can be omitted. Instead of outputting a percentage for every step, it outputs at the end. Maybe it is a difference in the flags returned by the ode45 function.
  2. Had to add 'InitialStep', 0.001 to the odeset parameters - or else the error becomes too large and ode45 exits.
  3. Instead of Z which was linspace(0, flength, nsaves), gave [0, flength] as the parameter to ode45 - or else the ode45 in Octave ignores RelTol and AbsTol. 
  4. Then, spline to create a linearly spaced array of our desired spacing.
So, instead of 
[Z, AW]=ode45( @rhs, Z, ifft(A), options .... etc
called it as
[Zoctave, AWoctave]=ode45( @rhs, [0, flength], ifft(A), options .... etc
and then
Z     = linspace(0,flength, nsaves);
AW = spline(Zoctave, AWoctave,Z);

Then, running time - 

Octave modified ugnlse = 166 sec on i7
Matlab  = 281 sec on Athlon

Since python code got 9x speedup on the i7, I guess the Octave ode45 + spline is slower than the Matlab ode45. Still, running on the i7 gets the advantage of more RAM. Doesn't give the out of memory error so easily. 

Monday, February 06, 2017

pynlo on Linux Mint running on i7 Macbook Pro 4GB

Got a Macbook for doing some tests, computations etc.
OS X Snow Leopard 10.6.8
Intel Core i7
2.66 GHz
2 cores

Made it dual boot with Linux Mint 18.1 Cinnamon using rEFInd, installed Anaconda 2.7 for pyNLO.

Anaconda installed with no issues. But pip install needed
apt-get install python-pip
apt-get install python-setuptools
apt-get install python-dev

pip install pyfftw
gave permission errors, so did
pip install pyfftw --user
apt-get install libfftw3-dev

python did not work - no module named matplotlib
pip install matplotlib --user

Then needed
apt-get install python-tk

Finally working. But colours were different in the pcolor plot.

Changed colormap of pcolor using
cmap=plt.get_cmap('viridis') inside pcolor function call.

On my Athlon 32 bit Windows XP laptop - - runs for 15:33 = 933 sec and Mem Error
On the i7 - the same script runs for 1:42 = 102 sec, no Mem Error

So, more than 9x faster.

Sunday, February 05, 2017

status page from uptimerobot have created status pages now, which can be made public also. Our status page is at

Had to make the custom url a redirect, could not make it a subdomain, since Cloudflare complained that two separate accounts cannot CNAME each other. 

Tuesday, January 31, 2017

trying vlc-warp build and other warping on Macbook

The vlc-warp code, when directly tried a build on Linux Mint 18.1 running on an i7 Macbook Pro, gave the error that
configure: error: libavcodec versions 56 and later are not supported yet.

When compiling on a Live DVD of Ubuntu 12.04, compiles OK. But that build will not run on the Linux Mint 18.1 with accelerated graphics. And the Live DVD will not boot with accelerated graphics! So, as of now, am pausing these efforts.

Trying the recommended way to compile on Mac OS - that needs the latest version of Xcode, and our Mac is running 10.8 Snow Leopard.

Tried the Quartz Composer patch from Paul Bourke - that also had some version compatibility issues, I guess, did not work on first few attempts.

Then directly tried the compiled warp-player from Paul Bourke - that itself was skipping frames when trying to warp and play a 50 Mbps 2K fulldome movie. So, pausing these efforts to make a realtime warping player work on this machine. 

Monday, January 30, 2017

Airtel SIM language selection loop

An occasional problem with Xiaomi Mi3 phone - Airtel sim language selection menu comes up again and again - seen for example after a change of SIM.

Solution seems to be to shut down the phone and start it again.

Wednesday, January 25, 2017

Fisheye to Equirectangular

Jason Fletcher has a post about converting footage from Fisheye to Equirectangular in After Effects. Similar to my Photoshop conversions to fisheye, but the other way around. Would be a useful reference for my conversions - by seeing where the images appear.

Wednesday, January 04, 2017

Airtel 3G speeds

To add to my Jio speed test posts, here are Airtel 3G speeds 3-4 pm at Puttaparthi - the times are visible in the top left corner. Not too shabby :) and definitely better than Jio during peak times.

And, a few days ago at 8.15 pm, with Airtel dongle,

Monday, January 02, 2017

offline fulldome option on Macbook pro - Gaia Sky

Since I had trouble compiling Stellarium360 to run on the Macbook Pro I have got as a loaner, tried out other options - Gaia Sky has a planetarium mode. But fisheye only, no support for mirror-dome. At high resolutions, my machine is unable to keep up refresh rates with Gaia Sky. But it could be used for offline rendering.

stellarium360 on Linux Mint 18.1

Linux Mint 18.1 Cinnamon works fine, dual booting with Mac OS 10.6.8 Snow Leopard, on an i7 Macbook Pro. Mageia Linux, the recommended option for Stellarium360, blanks the screen and / or crashes the system while trying to boot. So, tried compiling Stellarium360 on Linux Mint 18.1. But ran into problems.

ran the install dependencies for Ubuntu script, and ran ./configure. Configure complains that
checking for SDL2/SDL_image.h... yes
checking GL/glew.h usability... yes
checking GL/glew.h presence... yes
checking for GL/glew.h... yes
checking for ptrdiff_t... yes
checking for GraphicsMagick++-config... yes
checking for sdl2-config... yes
checking whether byte ordering is bigendian... no
checking for dirent.h that defines DIR... yes
checking for library containing opendir... no
checking for fabs in -lm... no
math library not found
checking for Mix_OpenAudio in -lSDL2_mixer... no
configure: error: *** SDL2_mixer library not found -  ***

libsdl2-mixer-dev is already the newest version (2.0.1+dfsg1-1).

I believe this has something to do with changing
-lSDL2_mixer to -lSDL2 or something like that at some point in the configure script, because the API call MixOpenAudio has shifted from one header to another or something? Not sure, just a guess.

But meanwhile, I thought Stellarium360 would work with spherical mirror systems also. Since it won't, then I will pause and rethink my efforts :)