Freifunk

Huh, it’s Freifunk time. Open WiFi and fresh mesh networking is recently going on in Darmstadt and other beautiful cities like Lübeck or Berlin.
(Community overview at the Freifunk Wiki.)

I was totally baffled how easy it is to set up a Freifunk node. Though I’m glad that the awesome people from Chaos Darmstadt were at my side for the first time setup.
After setting up a TL-WDR4300 with their help, I successfully installed the recent Gluon firmware at an older TP-LINK WR1043ND I still had lying around today and it was as easy as I remembered it.

Spread the word, go, get out and do some Freifunk <3

Panasonic GH3 Color Profiles

Today I shot a grey/color chart with the Panasonic GH3 at ISO 200, my new on-camera light “Kaiser Star Cluster” and the 12-35mm at f4.0, showing different picture settings at 0 0 0 0 with manual in-camera white balance matched to 5600K.

Based on the dynamic range that is visible on the grey chart, I’d choose NATURAL or PORTRAIT as a base for my future projects.
Furthermore I find the NATURAL and STANDARD colors most pleasing and accurate by default whereas NATURAL has a little less blue shift.

I additionally learned that with a correct manual white balance the camera adds a little too much blue so I’m going to consider that in my camera settings.

MONOCHROME

MONOCHROME

MONOCHROME color chart details

MONOCHROME color chart details

MONOCHROME grey chart details

MONOCHROME grey chart details

NATURAL

NATURAL

NATURAL color chart details

NATURAL color chart details

NATURAL grey chart details

NATURAL grey chart details

PORTRAIT

PORTRAIT

PORTRAIT color chart details

PORTRAIT color chart details

PORTRAIT grey chart details

PORTRAIT grey chart details

SCENERY

SCENERY

SCENERY color chart details

SCENERY color chart details

SCENERY grey chart details

SCENERY grey chart details

STANDARD

STANDARD

STANDARD color chart details

STANDARD color chart details

STANDARD grey chart details

STANDARD grey chart details

VIVID

VIVID

VIVID color chart details

VIVID color chart details

VIVID grey chart details

VIVID grey chart details

 

GH3 COLOR OVERVIEW

GH3 COLOR OVERVIEW

Panasonic G6 Color Profiles

Today I shot a grey/color chart with the Panasonic G6 and the 12-35mm at different picture settings with manual in-camera white balance.

Here you can download white balance presets for Resolve based on each of the exported settings after I adujsted the grey chart shots for each possible picture setting at 0 0 0 0. Maybe this could be handy when you were able to control the lighting but did not bring a greycard to your set.

Based on the dynamic range that is visible on the grey chart, I’d choose NATURAL or PORTRAIT as a base for my future projects. Comparing the color charts I find the reds in PORTRAIT much more present compared to NATURAL.

VIVID grey chart details

VIVID grey chart details

VIVID grey chart

VIVID grey chart

VIVID color chart details

VIVID color chart details

VIVID color chart

VIVID color chart

STANDARD grey chart details

STANDARD grey chart details

STANDARD grey chart

STANDARD grey chart

STANDARD color chart details

STANDARD color chart details

STANDARD color chart

STANDARD color chart

SCENERY grey chart details

SCENERY grey chart details

SCENERY grey chart

SCENERY grey chart

SCENERY color chart details

SCENERY color chart details

SCENERY color chart

SCENERY color chart

PORTRAIT grey chart details

PORTRAIT grey chart details

PORTRAIT grey chart

PORTRAIT grey chart

PORTRAIT color chart details

PORTRAIT color chart details

PORTRAIT color chart

PORTRAIT color chart

NATURAL grey chart details

NATURAL grey chart details

NATURAL grey chart

NATURAL grey chart

NATURAL color chart details

NATURAL color chart details

NATURAL color chart

NATURAL color chart

ISO Comparison GH2 vs. G6 vs. GH3

As long as I still have the three beauties from Panasonic at home, I thought about doing a comparison to decide which one I’ll keep, and because some others may ask themselves a similar question: Here it is, the first excerpt of my comparison experiments:

All Shots are done with the Panasonic 20mm f1.7 at f3.2 with shutter speed set to1/25th at AVCHD 24p, Standard picture profile at 0 0 0 0 and manual WB 10000K.

The GH2 is hacked with Driftwood’s T7 Moon high bitrate hack. And because Nick Driftwood recommends it for 24p video, the GH2 uses i.Dynamic at LOW.
G6 and GH3 have intelligent settings disabled.

I found it very hard to match the cameras via their color profiles so I decided to use STD 0000 on all of them.

For post production in After Effects and Premiere, I decided to convert all shots to DNxHD first.
Sorry for the poor white balance, but I just had one LED spot that was dimmable and no proper video light. I then decided to leave it as it is and did not apply any color grading in post.

I’m going to publish a comparison at ISO 800 with some more individually optimized settings on each camera and – as far as my skills go – some optimization in post.

 

Bitrate and Framerate – Some Math

I recently tricked myself comparing different framerates with matching bitrates and I’d therefore like to write an example down.

Example for Panasonic G6
AVCHD 50p 28Mbps => 0.56 Mbit/Frame
AVCHD 25p 24Mbps => 0.96 Mbit/Frame
AVCHD 24p 24Mbps => 1 Mbit/Frame

Therefore be aware that in this case 24p got – technically – the most imformation per frame eventhough 50p 28Mbps might at first seem better.

Panasonic G6 – noise and grain

Compared to the hacked GH2 I almost fell off my chair looking at the footage of my newly bought Panasonic G6 because there was heavy grain.

I figured out that setting i.Dynamic to “high”, like I knew it from the hacked GH2, caused most of the noise. Turning this off increased the image quality a lot.

Depending on how deep you’d like to digg in post production, you can set noise reduction to 0 or -1 and use some of the in camera noise reduction. I also encountered good results with NR set to -3 and optional post processing.

Currently using STD -3 -3 -1 -3 with Panasonic lenses. STD 0 0 0 0 works well, too.
You can see a comparison of the two settings here:

A more detailed video on the G6 vs. GH2 (hacked) vs. GH3 will follow.

What test setups do you use and how do you measure exposure while testing different settings?
I find the in-camera exposure metering a little uncomfortable. Maybe I’ll try Zebra as orientation so I get the most light without overexposing.

Mister X Team

During the last days I figured out a really cool kind of team based ground game.

the basis

Some of you might know the legendary “Scotland Yard” or the newer board game “Mister X” by Ravensburger, who some time ago decided to publish an app (iOS, Android) called Mister X mobile to put the hunting scenario from the board game into a real world environment.

Within the app the so called detectives see eachother and every two minutes (time interval is variable) the position of Mister X, who in turn is continuously notified about the detectives’ positions. The game ends when at least one detective caught Mister X. To prevent being caught resp. as detective being recognized there are a few items you can choose from your virtual bag to confuse your opponent.

the creation “xTeam”

With some of my best freinds I tried to transfer this game into a more of a ground game like competion mode. To achieve that we played two Mister X mobile sessions across.

Each of the two teams had a base within the playing area, Mister X, detectives and scouts, also every player had to wear a wristband in the color of his team (except the both Mister X wore a white one).

Mister X had to be caught by the opponent detectives like in the original game.

A detective had to catch the opponent Mister X and was abled to catch opponents by removing their wristband.
After losing the wristband a detective had to go back to his base and get a new one while having no opporunity to catch someone else.

A scout has been invented due to the fact that not all of us had a smartphone with access to the internet and GPS. These players were invisible for the opponent Mister X and did not see the position of anyone else on the map beacause they were not registered within the Mister X mobile app game. For this reason they mostly sticked to a detective teammate.
To prevent the two Mister X from too much surprise whe did not allow the scouts to catch Mister X but to remove wristbands of other detectives/scouts.
Scouts had to get a new wristband like detectives when they lost theirs.

the setup

  1. each team went to its base and planted a box containing their wristbands
  2. one wristband for each player
  3. the two Mister X met in the middle of the playing area to initialize the two Mister X mobile games on their smartphones
  4. the matching players joined the opponent Mister X on the app game
  5. and after everyone confirmed he was successfully added to the right group the game started

the upgrade

For communication purposes we used What’s App, phone calls and SMS but they came in quite unhandy. As a solution to this we plan to equip ourselves with some radio devices with headsets attached to make communication a lot more comfortable and give the scouts a lot more use.

At this one day we were around 10 people so 1 Mister X and 4 detectives/scouts playing within a 700m readius and only by foot.
We threfore thought of getting more people into it and maybe use public transport or bikes to increase flight possibilities for Mister X.

 

“pci passthrough” howto

Aims

With this howto you got the chance to set up a Windows virtual machine that is capable of playing video games on a Linux host.
For additional information read “pci passthrough” vs. “vga passthrough” first. Also see the intro post for the hardware I use.

Prepare System

  • activate vt-d in your BIOS
  • set chipset video card to always on
  • install fresh _Ubuntu 12.04 (I chose XUbuntu)
    (For _Ubuntu 12.10 see additional information here.)

Installation

With installing Xen I followed the wonderful Ubuntu Community but I will tell you the important steps right here, too.
(I’m assuming you got root by sudo -i, so “sudo” is left out.)

Install and check the Xen kernel.

apt-get install xen-hypervisor-amd64
sed -i 's/GRUB_DEFAULT=.*\+/GRUB_DEFAULT="Xen 4.1-amd64"/' /etc/default/grub
update-grub
sed -i 's/TOOLSTACK=.*\+/TOOLSTACK="xm"/' /etc/default/xen
xm list

“xm list” should output something like “Domain-0″ representing your Dom0 (host) after a reboot with the Xen kernel.

Set network up. (You could also disable network-manager permanently if you like.)

apt-get install bridge-utils
/etc/init.d/network-manager stop

Change network configuration in /etc/network/interfaces.

auto lo
iface lo inet loopback

auto xenbr0
iface xenbr0 inet dhcp
    bridge_ports eth0

auto eth0
iface eth0 inet dhcp
/etc/init.d/networking restart

Create the volume group “virtual-machines” and add a 100GB volume. (sdb is an empty HDD without any partitions, you may change this as you need.)

vgcreate virtual-machines /dev/sdb
lvcreate -L 100G -n win7x64 virtual-machines

Get the addresses of the pci devices you want to pass through. (Here I’m directly grepping for USB and VGA devices.)
Note: For my HD7950 and other newer video cards you always need to get 2 pci addresses. I found out ’01:00.0′ by the following command and had to add ’01:00.1′ as well to my config file. I assume the second address is responsible for audio stuff.

lspci | grep VGA
lspci | grep USB

Save the following lines as /etc/xen/win7x64-hvm.cfg and change them as you like.

# nut sure if really needed
kernel="/usr/lib/xen-default/boot/hvmloader"

builder = "hvm"
name = "win7x64-hvm"

# RAM size in MB
memory = "4096"

# number CPU cores
vcpus = 2

vif = ['type=ioemu']

# boot from cd and hdd
disk = ['phy:/dev/virtual-machines/win7x64,hda,w','file:/home/user/images/WIN_7_PROFESSIONAL.iso,hdc:cdrom,r']
boot="dc"

# boot from hdd
#disk = ['phy:/dev/virtual-machines/win7x64,hda,w']
#boot="c" 

# enable remote vnc access until video card driver is installed
vnc = 1 

acpi=1
sdl=0
serial='pty'

# list your pci devices (HD7950,HD7950,USB)
pci=['01:00.0','01:00.1','00:1a.0']

Enable pciback module.

modprobe xen-pciback

Create the following bash script to reassign your PCI devices to the virtual machine/pciback and execute it.

remove_device () {
BDF=$1
# Unbind a PCI function from its driver as necessary
[ ! -e /sys/bus/pci/devices/$BDF/driver/unbind ] || \
echo -n $BDF > /sys/bus/pci/devices/$BDF/driver/unbind
# Add a new slot to the PCI Backend's list
echo -n $BDF > /sys/bus/pci/drivers/pciback/new_slot
# Now that the backend is watching for the slot, bind to it
echo -n $BDF > /sys/bus/pci/drivers/pciback/bind
}

#usb controller
remove_device "0000:00:1a.0"
#HD 7950
remove_device "0000:01:00.0"
remove_device "0000:01:00.1"

Create and start your vm.

xm create /etc/xen/win7x64-hvm.cfg

Install vncviewer and connect to the virtual machine.

apt-get install vncviewer

vncviewer localhost:0

Install Windows, video card driver, connect 2nd screen to passed video card and reboot the vm.

I advice you to change the config file and exclude the CD image so the vm is only booting from hdd.

To get the network working you may need to install XEN Windows drivers located here. (additional info)

Results

I don’t like excessive benchmarking but here are some facts about the system.

Team Fortress 2 at 300FPS on High.

Windows7 performance index. (HDD score may be improved by directly passing the SATA controller as well.)
Leistungsindex Windows7 PCI Passthrough XEN

Fixes & Tipps

If you get an error like “device not ready for commands” open the qemu log.
The error “couldn’t find keymaps/en-us” could be fixed by creating the following symlink.

ln -s /usr/share/qemu-linaro /usr/share/qemu

If you are told that a specific pci address has to be assigned to the same guest as another you are probably missing the second pci address of your video card. (see “Get the addresses of the pci devices you want to pass through.” on above)

For the people out there who tried this howto: I’d totally love to hear how it is going and if this howto needs an update.

Links

  • https://help.ubuntu.com/community/XenProposed
  • http://wiki.ubuntuusers.de/Logical_Volume_Manager
  • http://phoronix.com/forums/showthread.php?57068-Xen-VGA-passthrough-is-the-way-to-go!!! (beginning at page 6 or 7)

“pci passthrough” vs. “vga passthrough”

If you have multiple video cards and you want to use one for your Dom0 aka host and the others for your VM, “PCI Passthrough” is the path to take because it is way easier to setup. In conclusion this is what I will try first because I have my HD7950 and the i7 integrated Intel 2000.

On the other hand if you just have one video card (e.g. in a laptop) you have to deal with a little patching and kernel compiling to get your video card to the client. Maybe I will try this later on even though I do not need to.

influences on learning processes

Getting together with an old friend today who came back home from her psychology studies in York (best graduate of whole university *proud*) Thanks to her I’ve already learned something that may expect me during my future Psychology in IT studies in Darmstadt:

When you learn something e.g. under water and you try to remember it later on it will be a lot easier if you are under water again. Things you learn are always connected to your environment (location, time, etc.) and mood. In conclusion it would be a great idea to study in a silent room because during your exams your are – drum roll – in a silent room.

Another interesting fact is that nearly half of our brain is part of our visual system, so when you connect facts to images, memorizing them works like a charm. For example take a ball and the toilet (props to my dear psychologist for this wonderful example) that do not have that much in common unless you put the ball into a toilet. Can you imagine that?
If I were to ask you for a ball tomorrow I am absolutely confident that the ball-in-the-toilet image will appear again.