Go to advanced search

by ghans
Tue Jan 22, 2019 7:45 am
Forum: Beginners
Topic: Convert Audio/Video data through USB into binary stream at gpio pin
Replies: 3
Views: 90

Re: Convert Audio/Video data through USB into binary stream at gpio pin

For video, study the V4L2 API. For audio, study the ALSA API.

Please note those APIs are only directly exposed to C. For Python you will need wrappers
(multiple exist).


ghans
by ghans
Tue Jan 22, 2019 7:37 am
Forum: General discussion
Topic: MJPEG video
Replies: 3
Views: 81

Re: MJPEG video

The Raspberry Pi h.264 hardware video encoder does not support 4K. Running at full HD (1080 × 1920) is the maximum.

MJPEG doesn't seem to have the same restrictions.

ghans
by ghans
Tue Jan 22, 2019 7:23 am
Forum: Graphics programming
Topic: Best way to render video inside my program?
Replies: 5
Views: 114

Re: Best way to render video inside my program?

Most likely, the easiest way is using omxplayer from your program. omxplayer allows control and querying via the MPris2 protocol.

ghans
by ghans
Sat Jan 19, 2019 10:07 am
Forum: Advanced users
Topic: Virtual com port drivers?
Replies: 8
Views: 240

Re: Virtual com port drivers?

Those devices are created by "udev". USB devices become plug-and-play thanks to udev, too.

ghans
by ghans
Fri Jan 18, 2019 7:06 am
Forum: Beginners
Topic: Convert Audio/Video data through USB into binary stream at gpio pin
Replies: 3
Views: 90

Re: Convert Audio/Video data through USB into binary stream at gpio pin

Which programming languages do you know ?

ghans
by ghans
Wed Jan 02, 2019 3:25 am
Forum: Deutsch
Topic: RaspberryPI 1 b+ als tastatur?
Replies: 2
Views: 197

Re: RaspberryPI 1 b+ als tastatur?

Keines der B Modelle kann als Tastatur fungieren. Die Zero - und A Modelle können es hingegen schon - sogar recht einfach, vorausgesetzt du sprichst flüssig "Linux". Die B Modelle haben alle einen Ethernet-USB-Hub-Combochip der alle Ports in den Hostmodus zwingt. Beim Rest gibt es eine direkte Verbi...
by ghans
Tue Dec 25, 2018 6:13 pm
Forum: Graphics, sound and multimedia
Topic: Slightly glitchy sound producing tones via GPIO pins
Replies: 7
Views: 267

Re: Slightly glitchy sound producing tones via GPIO pins

The Raspberry Pi has a PWM peripherial which sidesteps timing issues. I believe that it is available through WiringPi.

Being able and willing to interrupt processes by force is a feature of all so-called preemptive operating systems like Windows, Linux and Mac OS X.

ghans
by ghans
Wed Dec 19, 2018 7:35 am
Forum: Advanced users
Topic: Raspivid + WebRTC + getUserMedia() = ?
Replies: 3
Views: 695

Re: Raspivid + WebRTC + getUserMedia() = ?

Try loading the official V4L2 driver:

Code: Select all

sudo modprobe bcm2835-v4l2
No idea if it supports two cameras. You should play around with v4l2-ctl (part of v4l-utils).

ghans
by ghans
Wed Dec 19, 2018 7:22 am
Forum: Raspbian
Topic: Launch a .jar with GUI on Raspbian Stretch Lite boot
Replies: 4
Views: 979

Re: Launch a .jar with GUI on Raspbian Stretch Lite boot

You can try to install the X server + openbox + lightdm on Raspbian lite to fix this:

Code: Select all

sudo apt-get install xserver-xorg-core xserver-xorg-input-all xserver-xorg-video-fbdev libx11-6 x11-common x11-utils x11-xkb-utils x11-xserver-utils xterm lightdm openbox
ghans
by ghans
Fri Dec 14, 2018 5:59 am
Forum: Other programming languages
Topic: Chromium and Raspbian lite, programmatic control
Replies: 4
Views: 716

Re: Chromium and Raspbian lite, programmatic control

Professional browser automation is done with Selenium and the WebDriver protocol. The latter is already supported by Chromium AFAIK. I am not convinced that an embedded webserver isn't the cleanest solution. The seperation between server and client is a positive, since you normally want to swap the ...
by ghans
Wed Dec 12, 2018 5:44 am
Forum: Other projects
Topic: Developer new TFT LCD driver for Linux RPI
Replies: 6
Views: 295

Re: Developer new TFT LCD driver for Linux RPI

Have a look at "tinydrm":
https://github.com/notro/tinydrm/wiki

tinydrm was explicitly designed for writing simpler LCD drivers, especially on the Raspberry Pi.

ghans
by ghans
Fri Dec 07, 2018 6:30 am
Forum: Troubleshooting
Topic: Data Retrieval from corrupted file system raspberry pi SD card
Replies: 5
Views: 249

Re: Data Retrieval from corrupted file system raspberry pi SD card

@anaTech Why are you working with /dev/mmcblk0pXX ? That is obviously the internal SD card which is currently in use. The SD card in the reader should be called differently. To make sure, unplug the reader with card and replug it. Now sudo dmesg | tail should show you the name of the external SD car...
by ghans
Wed Dec 05, 2018 9:04 am
Forum: Troubleshooting
Topic: Data Retrieval from corrupted file system raspberry pi SD card
Replies: 5
Views: 249

Re: Data Retrieval from corrupted file system raspberry pi SD card

Do not try to upload photos here (heavy filesize restrictions), use imgur.com instead. What you want to do is following: 1) Make an image backup of the old card with dd (You need enough free space). sudo dd if=/dev/sda of=/path/to/imgfile.img bs=4K If you don't have enough space you can skip to step...
by ghans
Wed Dec 05, 2018 8:28 am
Forum: Python
Topic: Display simple image on GPIO screen
Replies: 12
Views: 697

Re: Display simple image on GPIO screen

You seem to be using devicetree overlays, which is excellent.
I propose that you use guizero.

guizero is a GUI library specially written for beginners.
It comes very close to your pseudo-code because of this.

https://lawsie.github.io/guizero/images/

ghans
by ghans
Tue Dec 04, 2018 8:06 am
Forum: Python
Topic: Display simple image on GPIO screen
Replies: 12
Views: 697

Re: Display simple image on GPIO screen

How did you get the screens work in the first place ? Which commands did you enter ? Which configuration files did you modify ? Do you have more than one screen attached to your Pi ?
What is currently displayed on your screen ? The desktop ? The command-line ?

ghans
by ghans
Thu Nov 29, 2018 6:19 am
Forum: Other programming languages
Topic: [Apache] Clean links?
Replies: 5
Views: 1139

Re: [Apache] Clean links?

You must rename files on the server if it bothers you this much.
This process is called "precent encoding" and your browser is just doing its job by using it.

ghans
by ghans
Tue Nov 27, 2018 10:06 am
Forum: Camera board
Topic: Usb camera does not use GPU
Replies: 9
Views: 883

Re: Usb camera does not use GPU

USB cameras can not be accelerated. The overheads are innate to USB camera devices. The only exception would be cameras with integrated h.264 encoder. They could send the compressed data to the inbuilt h.264 decoder of all Raspberry Pis and then the Pi could display it, circumventing the CPU. Those ...
by ghans
Tue Nov 27, 2018 7:28 am
Forum: Deutsch
Topic: Multiple Kamera
Replies: 2
Views: 1147

Re: Multiple Kamera

Man kann mit dem Multi-Kamera-Adapter nicht mehrere Kameras gleichzeitig benutzen, sondern nur alle abwechselnd.
Außerdem braucht es ein Weilchen zum Umschalten. Die Umschaltzeit kann auch schwanken.

ghans
by ghans
Sun Nov 25, 2018 8:44 am
Forum: Beginners
Topic: Trying to install OpenCV, running into errors, what does "cd ~" mean?
Replies: 3
Views: 227

Re: Trying to install OpenCV, running into errors, what does "cd ~" mean?

~ is an abbrevation for your home directory, that is "/home/$username" where $username gets replaced by the current username (duh). The diectory "opencv" did not exist yet inside ~ . You did the sensible thing and created it. So far, so good. Next you tried to install cmake via pip. A rule of thumb:...
by ghans
Sat Nov 24, 2018 10:03 am
Forum: General discussion
Topic: Nothing goes as we say in Quebec - NOOBS issue
Replies: 11
Views: 516

Re: Nothing goes as we say in Quebec

1. Download Etcher and install it: http://www.etcher.io 2. Download Raspbian https://downloads.raspberrypi.org/raspbian_full_latest 3. Put the SD in your laptop/desktop PC. 4. Start Etcher and "burn" Raspbian onto your SD card. 5. Eject the SD card. 6. Put the card into your Pi and start it. 7. Prof...
by ghans
Sat Nov 24, 2018 9:43 am
Forum: Beginners
Topic: Info about librarys to the Pi...
Replies: 2
Views: 223

Re: Info about librarys to the Pi...

The help system on Linux is called "manpages". Section 3 covers library functions. Type man 3 intro for an introduction to section 3. Nearly anything and everything on Linux has a manpage. Including the "man" command itself. To search manpages, try the "apropos" command. Try to to find the manpages ...
by ghans
Tue Nov 20, 2018 7:42 am
Forum: Bare metal, Assembly language
Topic: Enable Bluetooth/Wifi Rpi Zero W Bare Metal
Replies: 10
Views: 2053

Re: Enable Bluetooth/Wifi Rpi Zero W Bare Metal

Broadcom sold its Bluetooth division to Cypress ...

http://www.cypress.com/file/298076/download

ghans
by ghans
Sat Nov 17, 2018 9:01 am
Forum: General discussion
Topic: Can I put photo's on the SD-card and read it with an arduino?
Replies: 8
Views: 380

Re: Can I put photo's on the SD-card and read it with an arduino?

Quick format is indeed quicker and causes less wear. The only drawback is that
that data is not overwritten but just marked as "empty" so with easily available software
your top secret cookie recipes could be recovered.

ghans
by ghans
Fri Nov 16, 2018 9:43 am
Forum: Deutsch
Topic: Backup-Gerät für SD-Karten? Vergleichbar mit WD Passport Wireless Pro, aber schneller?
Replies: 4
Views: 1630

Re: Backup-Gerät für SD-Karten? Vergleichbar mit WD Passport Wireless Pro, aber schneller?

Alle Raspberry Pis haben einen 480 Mbit/s USB 2.0 port.
Da hängt eine 4-Port-USB-Hub-plus-Ethernet-Kombi dran. Soweit ich weiß, bedeutet dies die Aufteilung der 480 MBit auf alle fünf (oder weniger) Geräte.

ghabs
by ghans
Thu Nov 15, 2018 7:01 am
Forum: Deutsch
Topic: Backup-Gerät für SD-Karten? Vergleichbar mit WD Passport Wireless Pro, aber schneller?
Replies: 4
Views: 1630

Re: Backup-Gerät für SD-Karten? Vergleichbar mit WD Passport Wireless Pro, aber schneller?

Ist dein Projekt mit einem Pi umsetzbar : Ja. Erreicht du dein Perfomance-Ziel mit einem Pi : Nein. Viel viel würdest für dieses Projekt maximal ausgeben ? Hast du Erfahrung mit Batchdateien unter Windows ? Um dieses Projekt abzuschließen, wirst du dich mit Raspbian (ein Linux) auseinandersetzen müs...

Go to advanced search