Tag: linux

UVC webcam upside down image

I have a laptop with a buld-in webcam. This would normally be all well and good, but the damn thing has a problem with the picture being upside down…

If you have the same problem, here is the solution:

  1. Download the new uvcvideo from here and extract it.
  2. Extract the file (tar xjvf uvcvideo.tar.bz2)
  3. Get one of the patches: 1_mirrored, 1_notMirrored, 2_mirrored, 2_notMirrored (courtesy of arjos85)
  4. Save the patch in the folder ~/linux/drivers/media/video/uvc/uvc_video.c (~ is the path to the just downloaded and extracted driver)
  5. Then run: patch -p0 < [your_patch]
  6. Now build the module: make && make install
  7. load it with: modprobe uvcvideo

Now everything should be working correctly. Try it with Skype or Cheese!

Let me know if there were any problems…

How to re-encode videos using MPlayer

Hi,

It often happens to me that I get sent a video and it turns out to be unnecessarily huge. I think nowadays people record videos with a digital camera or an older camcorder – but this isn’t really important…

If you use Windoze, there are probably hundreds of programmes that you could use to re-encode videos, provided you pay a license fee or steal the software. Linux however this comes free for all of us and it’s fairly easy to do from the trusty shell (console, prompt…). In addition you will find that you can change aspect ratio, frame rates and do other processing functions easily using MPlayer. In addition, MPlayer crosscodes nearly all media files, certainly most I have ever come across…

The prerequisit is that you get MPlayer and their codec-pack installed. You can find that here: http://www.mplayerhq.hu/. If you use ubuntu, you should be able to do something like:

sudo apt-get MPlayer

to install the player using the package manager.

Let me know if there is need for more detailed instructions on how to install MPlayer…

There are different codecs for re-encoding for both audio and video. It’s also not always possible to convert the audio part of a file into something much better – and why would you, it’s not going to sound better!

Next, we need the massive video file that we’d like to shrink. Simply navigate to the folder it is in. To encode with standard settings, using the liblav codec (for DivX), try this command:

mencoder -ovc lavc inputFile -oac mp3lame -o outputFile

This will re-encode the file, but this mightn’t be using the best settings for your needs, so I’m going to intruduce a few more features:

Need to fix a broken index in your video file:

mencoder -idx input.avi -ovc copy -oac copy -o output.avi

Want to merge a few media files? This is for you (be sure that they are the same format etc…):

cat 1.avi 2.avi | mencoder -noidx -ovc copy -oac copy -o output.avi

Here’s a simple command that converts an MPG file to AVI format:

mencoder file.mpg -o file.avi -ovc lavc -oac lavc

-ovc and -oac represent the options for the video and audio codecs that mencoder will use. To find out what video codecs are installed on your system, use mencoder -ovc help and mencoder -oac help.

Suppose you need a file with no compression on the audio part and decide to use PCM. You can specify the type of audio codec you want by using the acodec option:

mencoder file.mpg -o file.avi -ovc lavc -oac lavc -lavcopts acodec=pcm

When it comes to MP3 compression, you can also choose a bitrate using abitrate:

mencoder file.mpg -o file.avi -ovc lavc -oac lavc -lavcopts acodec=libmp3lame:abitrate=128

You can use lameopts if you have libmp3lame installed and want to add extra options to the encoding process. You can also create files with variable bit rate audio compression:

mencoder file -o file.avi -ovc lavc -oac mp3lame -lameopts vbr=2:q=3

where q can be any number between 0 and 9.

You can do the same thing with the video part of the file:

mencoder file.mpg -o file.avi -ovc lavc -oac lavc -lavcopts acodec=libmp3lame:abitrate=128 vcodec=xvid

If you don’t want to use video compression, try vcodec=copy. With that option, the frames will be copied one by one from the source file.

You can use xvid or divx directly, without going through lavc:

mencoder -ovc xvid -oac mp3lame -o destination.avi source.avi

If you need customized quality, you can add a few options to the XviD compression:

mencoder -ovc xvid -oac mp3lame -xvidencopts bitrate=878 -o destination.avi source.avi

The higher the bitrate, the better quality the video file will be. The downside is a larger file size.

Now let’s get fancy and make an XviD copy of a DVD using two passes. During the first pass, mencoder analyzes the content of the file; on the second pass mencoder encodes the new file based on the information obtained. By using two passes you can produce a better compressed file, but you’ll have to wait a little longer for it, and you’ll probably see CPU usage at 90% during the conversion:

mencoder dvd:// -oac mp3lame -ovc xvid -xvidencopts pass=1 -o /dev/null

mencoder dvd:// -oac mp3lame -ovc xvid -xvidencopts pass=2:bitrate=800 -o xvidfile.avi

You can use whatever bitrate option you want. If you need to squeeze a DVD into a 700MB XviD file, you could use the following command, which forces the file size of the resulting AVI to 700MB.:

mencoder dvd:// -ovc xvid -oac mp3lame -xvidencopts bitrate=-700000 -o file.avi

If you don’t like the CPU being used to the max and want to leave resources for launching other applications, use the nice option, which will run the program with the lowest priority when it comes to process scheduling:

nice -n 19 mencoder dvd:// -ovc xvid -oac mp3lame -xvidencopts bitrate=-700000 -o file.avi

Suppose you have a folder full of small video files of different types and would like to merge them into one big movie for easy watching. First, rename them so that they’re in the order you want them to appear in the final video, then use:

mencoder * -o output.avi

If you want to add a particular audio file to a movie, use:

mencoder source.avi -o destination.avi -ovc copy -oac mp3lame -audiofile file.wav (for uncompressed files)

mencoder source.avi -o destination.avi -ovc copy -oac copy -audiofile file.mp3 (for compressed files)

To convert a video file to run on a device running iPodLinux, use:

mencoder -ovc raw -ofps 15 -oac pcm -vf scale=176:-2,expand=176:132,format=bgr16 input.file -o output.avi

This produces a RAW AVI file with uncompressed audio data and scales it so it fits the Nano’s tiny screen perfectly.

I have a Pocket PC that I sometimes bring with me on business trips. I take a couple of movies I haven’t seen in a while and convert them to fit on a 512MB SD card:

mencoder -oac mp3lame -lameopts mode=3:preset=24 -ovc lavc -lavcopts vcodec=mpeg4:vhq:vbitrate=384:keyint=250 -vop expand=”320:240″ -o outputfile.avi inputfile.avi

or

mencoder input.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=200:abitrate=48 -vop scale=320:240 -oac copy -o output.avi

The difference here is that the latter command scales the file and the former fills the PDA’s 320×240-pixel screen with the movie.

If you have a webcam and want to record the output, use:

mencoder tv:// -tv driver=v4l:device=/dev/video0:width=640:height=480:forceaudio -ovc lavc -oac lavc -lavcopts vcodec=mpeg4:acodec=mp3 -ffourcc divx -o test.avi

The command records anything output by /dev/video0 in 640×480 resolution, using DivX with MP3 audio as an output result.

As you can see, you can use mencoder to convert almost any type of video file in several ways. It works fast, it works well, and I wouldn’t change it for any other application, be it GUI-friendly or not.

Kindest Regards to Kivilcim Hindistan – from whom I ripped some parts of this tutorial…

Switching off the Synaptic touchpad in Linux

If you are anything like me, you will find it annoying that your hand sometimes brushes against the touchpad of your laptop and – bang – the mouse has moved, the courser is misplaced and you have to correct what you have just written on…

Normally switching off the touchpad on laptops is easy, there will be a hotkey, but in Linux you will find not all ACPI options are working well and properly – or at all.

But it can be quite simple switching the touchpad on and off.

We need one step of preperation:

Open your xorg.conf as root (in my distro):
# sudo gedit /etc/X11/xorg.conf

Somewhere there should be this section:

Section “InputDevice”
Identifier “Synaptics Touchpad”
Driver “synaptics”
Option “SendCoreEvents” “true”
Option “Device” “/dev/psaux”
Option “Protocol” “auto-dev”
Option “HorizEdgeScroll” “0”
Option “SHMConfig” “on”
EndSection

It is important that you have this in there:
Option “SHMConfig” “on”

If that’s done, save and exit.

Next you will need to restart your graphic interface (so xorg.conf get’s loaded again). Simply press CTRL + ALT + BACKSPACE

Great, that’s done – now you can do this (as root):
# synclient touchpadoff=1
to switch it off, and:
# synclient touchpadoff=0
to switch it back on…

How to change the mouse polling rate in Ubuntu

Changing the mouse polling?

Special Thanks to: Cesare Tirabassi and everyone contributing in this thread

Beginner Tip: You must use sudo when editing these files.
Such as:

Code:
 gksudo gedit /etc/modules

Blackmagic’s solution:
Edit /etc/modules

Code:
gksudo gedit /etc/modules

Add these two lines onto the end:

Code:
-r usbhid
usbhid mousepoll=2

reboot.

Alternate solution that may work on Feisty (try the first one first):
Add

Code:
options usbhid mousepoll=2

on its own line at the end of /etc/modprobe.d/options

and then add

Code:
usbhid

on the end of /etc/modules
reboot

Alternate solution that may work on Edgy:
Add

Code:
options usbhid mousepoll=2

to /etc/modprobe.d/usbhid

and then add

Code:
usbhid

on its own line at the end of /etc/modules
reboot

aidanr’s alternate feisty solution
Create a file at /usr/local/bin/mymousesettings with the following inside:

Code:
#!/bin/bash
rmmod usbhid && modprobe usbhid mousepoll=2

or if you want to use lomoco (a program for changing the resolution on Logitech mice) you can use this instead:
(G5 and G7 mice don’t need lomoco because they are software-independant)
{
Install:

Code:
sudo apt-get install lomoco

lomoco’s Homepage: http://lomoco.linux-gamers.net/

Code:
#!/bin/bash
# -4 for 400 cpi, -8 for 800 cpi, -m for 1200 cpi, -h for 1600 cpi, -g for 2000 cpi
lomoco -h && rmmod usbhid && modprobe usbhid mousepoll=2

}

After doing either method enter the command

Code:
sudo visudo

and replace the line that says

Code:
%admin ALL=(ALL) ALL

with

Code:
%admin ALL=(ALL) ALL, NOPASSWD:/usr/local/bin/mymousesettings

Use Control + O and then hit enter to save and then use Control + X to exit.

Add that command to startup in System –> Preferences –> Sessions by clicking add and then adding

Code:
sudo sh /usr/local/bin/mymousesettings

as a new entry.
reboot

hanging the mouse polling?

Fixed it with the help of the Gentoo guide:
http://gentoo-wiki.com/TIP_Change_mouse_hz

I added

Code:
options usbhid mousepoll=2

to /etc/modprobe.d/usbhid
(using “sudo nano”)

and then I added

Code:
usbhid

on the end of /etc/modules

=)

Code:
$ cat /sys/module/usbhid/parameters/mousepoll
2

Here are all the mouse polls:

1 = 1000Hz
2 = 500Hz
4 = 250Hz
8 = 125Hz
10 = 100Hz (Default)

Fix the upside down on uvc webcams

Hi everybody,
it’s a very quick how-to that will help you to solve the problem of those webcams who give back upside-down images/videos!!!
This help is intended only for those who have a UVC capable webcam.
But it will be usefull only if your webcam supports YUV image format and the applications that use your webcam request YUV format to your webcam!!! I’ve tested it and it works with:
skype, amsn, kopete, luvcview, mplayer!!

So…let’s start!!!!

In order to know if your webcam is UVC capable you just need to open your shell and run:

Code:
lsusb


you will get something like this:

Quote:
Bus 002 Device 001: ID 0000:0000
Bus 001 Device 002: ID xxxx:yyyy “Your_Webcam_Model”
Bus 001 Device 001: ID 0000:0000

Then type:

Code:
sudo lsusb -d xxxx:yyyy -v | grep "14 Video"


If you get something like the following, your webcam is UVC capable:

Quote:
bFunctionClass 14 Video
bInterfaceClass 14 Video
bInterfaceClass 14 Video
bInterfaceClass 14 Video


If your webcam passes this test, you can go on reading. Otherwise, your camera needs to use propertary driver, because it doesn’t use standard protocol/command.

Well,
now you need to donwload the UVCVIDEO driver sources, but they are on a SVN repository, so you need to install the SVN client:

Code:
sudo apt-get install subversion

and now you can download the sources:

Code:
svn checkout svn://svn.berlios.de/linux-uvc/linux-uvc/trunk


The sources will be saved into a folder called “Trunk” in the path from where you run the previous command.

Next, you need to use a patch to update your clean uvcvideo driver. Please download this.

Then proceed..

Code:
patch < patch_solution1_mirrored.patch

Well, now the worst part has been done!!!
We just need to compile our modded file and to install the new driver, so from shell you have to go to the "Trunk" directory and type:

Code:
make

there shouldn't be errors!!

Then, ONLY if you are using one of the Ubuntu distributions (ubuntu, kubuntu, etc.), open with you editor the "Makefile" and change the following line:

Code:
INSTALL_MOD_DIR := usb/media

with

Code:
INSTALL_MOD_DIR := ubuntu/media/usbvideo

Now we just need to remove uvcvideo module (if you have previously installed it):

Code:
sudo modprobe -r uvcvideo

Then:

Code:
sudo make install
sudo modprobe uvcvideo

Now everything should work!!!

Let me know!!

Fix ‘Hardware error’ for Adobe CS2 running over wine

PERMANENT FIX: The permanent fix is actually very simple. The problematic file is the General Settings file, “Adobe Photoshop CS2 Prefs.psp”, which references the default fonts Adobe expects to be installed. If for any reason these fonts, or any other files, are not installed or not functioning as expected, the application will terminate to the desktop. This settings file is located here:

In Wine:

/home/[USER PROFILE]/.wine/drive_c/windows/profiles/[USER PROFILE]/Application Data/Adobe/Photoshop/9.0/Adobe Photoshop CS2 Settings/Adobe Photoshop CS2 Prefs.psp

In Crossover Office:

/home/[USER PROFILE]/.cxoffice/[CS2 INSTALLATION BOTTLE NAME]/drive_c/windows/profiles/crossover/Application Data/Adobe/Photoshop/9.0/Adobe Photoshop CS2 Settings/Adobe Photoshop CS2 Prefs.psp

Naturally, replace [USER PROFILE] with the user name you are working under, and replace the CS2 INSTALLATION BOTTLE NAME with whatever you named the bottle you installed Photoshop CS2 under in Crossover.

Now, if you’ve encountered this error, you’ve already run CS2 twice, and the settings file has already been created and corrupted. Although deleting it will allow you to start CS2, it will again store a corrupted file when you exit the application, and next time you start the application, you’ll repeat the same fatal error as usual.

So, having located this file, perform the following steps:

(1) Rename or delete the corrupted file
(2) Start CS2. It should start just fine.
(3) IMMEDIATELY after it has started, change the permissions on the newly re-created settings file (Adobe Photoshop CS2 Prefs.psp) to READ ONLY. You can do this in your file browser, or, if you are at the command line, use the following command:

chmod -w ./Adobe Photoshop CS2 Prefs.psp