operation:framegrabbing

Ephiphan Broadcaster operation

The best working settings depended on hardware generation, see Epiphan Broadcaster

The Admin-UI can be accessed by appending /admin to the URL (ie http://grabber3/admin). Login is in the Keepass.

Some projector setups require a custom resolution on the Broadcaster configuration to work properly.

Typical howto:

  • Generate a EDID file by connecting the mixer laptop (or another linux box) to the projector and run make-edid.pl.
  • cat/copy output to file on a machine with an web browser (currently not the mixer laptops, due to florolf ;-)
  • goto framegrabber settings
  • upload edid file via upload form
  • After replacing the EDID file, the Broadcaster does not need to be restarted. Dis- and reconnecting the cable from the computer's display port is sufficient.
  • If you see “Cannot update EDID. Please verify integrity and authenticity of the EDID file. E1011-3”, this is usually resolved by dis- and reconnecting the cable leading towards the projector.

How to get a EDID file:

If you want to force a special resolution, or subset of resolutions (e.g. prefer 16:9, no 16:10 only fallback 4:3)

Framegrabber settings: The Web admin interface contains most of the information that you need to make image adjustments including a brief description of the effect of each adjustment and the adjustment range. To make an adjustment, add a value to one or more fields and select Apply. To clear any adjustments, delete the value from one or more fields and select Apply. To have changes take effect, you must reboot the VGA Broadcaster Lite device. You can make more than one change before selecting Apply and rebooting.

Usually we use the MJPEG streaming function of the Broadcaster (why?), which can be accessed through http://10.73.x.2:1881/vgabroadcaster.mjpg on older generation models, and through http://10.73.x.2:1881/stream.mjpg on new gen models (called VGADVI Broadcaster).

Assuming a 16:9 projector, use the following line to feed the mjpeg stream to DVSwitch:

ffmpeg -i http://10.73.x.2:1881/vgabroadcaster.mjpg \
  -target pal-dv -loglevel error -aspect 16:9 - | \
  dvsource-file-voc -h "10.73.x.1" -i 1 -p 2000 /dev/stdin

This fetches the image off the framegraber and distorts it to fill the video image. If the projector requires a 4:3 resolution, uou first need to upload an EDID file to the broadcaster (see respective section). Next, you need to add artifical bars on the left and on the right by replacing above line in /etc/services/grabbersource by this (or by modfiying it accordingly):

ffmpeg -i http://10.73.x.2:1881/vgabroadcaster.mjpg \ 
  -filter:v 'scale=768:576, pad=1024:576:128:0 , scale=720:576' \
  -target pal-dv -loglevel error -aspect 16:9 - | \ 
dvsource-file-voc -h "10.73.x.1" -i 1 -p 2000 /dev/stdin

A final problem that you might be facing is a presenter with 16:9 slides. The computer of the speaker will add black rows on top and bottom to accomodate for the 4:3 aspect. In total, this will now have borders on all four sides and make the slides appear much smaller than necessary.

The recommendd workaround is to add a second source that cuts off the black bars received from the laptop. Run the following line inside a screen session on one of the encoders:

ffmpeg -i http://10.73.x.2:1881/vgabroadcaster.mjpg \ 
  -filter:v 'crop=h=3/4*in_h, scale=720:576' \
  -target pal-dv -loglevel error -aspect 16:9 - | \
dvsource-file-voc -h "10.73.x.1" -i 5 -p 2000 /dev/stdin

The broadcasters are available via 192.168.255.250, no matter which IP is configured on the web interface. To reach it, set up your computer with IP address 192.168.255.249 using 255.255.255.252 as netmask.

The integrated 4 GB USB stick fits 3-4 hours of video at 1280×720 (H264, incl. Audio). The broadcaster can be configured such that it doesn't record anything if there is no input signal (VGA/DVI).

It can take up to 10 minutes for the broadcaster to come up.

If you wish to replace the USB stick with a larger model, please make sure to ext-3-format the stick and move the files from the old stick. Do not use dd.

  • operation/framegrabbing.txt
  • Last modified: 2017/04/03 19:08
  • by andi