ITVLP - Internet TeleVision Linking Project
Ok ... so this is not an official project as such ... but if you can do it for Radio, why not television
There is now a Yahoo group especially for the ITVLP Project Set up by John KD5INM :
http://groups.yahoo.com/group/ITVLP/
Introduction
On the 9th August 2001 Tony Langdon VK3JED gave a talk at the NERGs on IRLP which he was
running on VK3RGL from time to time. being a bit of a computer hacker myself I was very interested
in hearing how the system worked, and was curious to see if the idea could be extended to include
video conferencing on the local amateur television repeater VK3RTV . I am not sure what the reactions
of the ATV repeater site would be to that :-) but I am sure it would do a great deal to advance the interest
in Amateur Radio.
Tony's web page is at:
http://www.qsl.net/vk3jed/
This page is a collection of notes and links to explore the posibility of putting together a ITVL Project.
The idea is basically to have a video conferencing package that listens to the output of an ATV repeater
using say a TV Tuner / Video capture card with low noise pre-amp, and use a video card on the computer
with TV output to transmit pictures to the ATV repeater input. In this way radio amateurs with
TV stations in different countries can video conference across the internet and the general amateur radio
operator with ATV receivers could watch the output of the ATV repeater. As now, amateurs could conduct
a voice link with the ATV operator via IRLP. They don't need to have an ATV transmitter to talk with someone
who does.
There is already significant use of computers with TV out video cards for generating graphics test patterns on ATV.
TV transmitter kits are readily available in Australia from places like Mini - Kits.
Video Conferencing Packages for Linux
qVIX/CU30
Cornell University have released a video conferencing package called qVIX/CU30 for Linux.
it is available from source forge at:
http://cu30.sourceforge.net/
Open H.323
Another interesting site for Linux video conferencing is the openH323.org site where they
are trying to deveop an open Video conferencing standard. What is good for us local
Aussies is that it is being pushed by an Australia company :-) I must say, I have not looked
closely at this site yet, but it does look very interesting
http://www.openh323.org/
Conferencing Overview
A brief over view of both qVIX/CU30 and H323 is available here:
http://www.techtv.com/screensavers/showtell/story/0,23008,3004942,00.html
Kmeeting
KDE video conferenceing based on Open H.323
http://sourceforge.net/projects/kmeeting/
Gnome Meeting
Video Conferencing for the Gnome Desktop Environment. (Open H.323
http://www.gnomemeeting.org/
CUSeeMe
Multimedia Conferencing.
http://www.cuseeme.com/products/cuseemeconferenceserver.htm
MBone
Multicast video conferencing and conference management
http://softlab-nsk.com/Pro/Mbone.html
Networking the Internet
First off IRLP needs a fast internet link such as Cable, ADSL and so on.
The approach taken by the IRLP group is to use Linux as the internet hub running the IRLP software
and run other computers on a local area network from than. Linux is used because it is far more stable that
windows, and does not require re-booting every day. The following site should tell you how to hook up
a fast internet connection to Linux and share the connection with a network of computers:
http://www.linuxathome.net/
Linux IP Masquerading
http://www.indyramp.com/masq/links.pfhtml
http://www.indyramp.com/masq/index.pfhtml
http://ipmasq.cjb.net/
Bt848 Based Capture Cards for Linux
Linux supports a number of video capture cards but the cheapest are based on the Brooktree Bt848
such as the FlyVideo and Miro PCTV tuner cards.
http://www.metzlerbros.de/bttv.html
http://bytesex.org/bttv/
Video4Linux is a mailing list and web site for video capture drivers for linux. It also has a number
of drivers for the Bt848 based cards as well as a number of other Video Capture/ TV Tuner cards.
http://roadrunner.swansea.linux.org.uk/v4l.shtml
Video 4 Linux
Frame Grabber Drivers for Linux
http://www.video4linux.net/
Video Display cards with TV out
In terms of video cards with TV Output, the following article suggests the ATI Rage cards are best for broadcast video and that the nVidia GeForce and TNT2 cards need scan convertors and genlocks for SCALA applications. They also say the ATI Rage family is near the end of it life cycle.
http://www.scala.com/miscellaneous-faq/video-card-recommendation.html
ATI All-In-Wonder
The ATI All-In-Wonder sounds like a pretty nifty card. It combines Graphics TV output with TV tuner input and is available in AGP or PCI. The PRO version appears to have been released in 1998 or there abouts The ATI All-In-Wonder 128 appears to be an upgrade and seems to includeMPEG1 and MPEG2 compression. Full motion MPEG2 needs a Pentium 3 to operate on the 128. For a 200MHz MMX Pentium, as I propose using MPEG1 at 352 x 240 seems to be the best you can do. I can already handle MPEG 1 with the Pinnacle systems Studio MP10 box that plugs onto the printer port and provides PAL input and output. The Studio MP10 is no longer supported by Pinnacle Systems and there does not appear to be any information on using the MP10 with Linux.
All-In-Wonder PRO
http://www.ati.com/na/pages/products/pc/aiw_pro/index.html
All-In-Wonder 128
http://www.ati.com/na/pages/products/pc/aiw_128/index.html
All-In-Wonder Radeon
Display/Tuner/Capture Card supported by Video4Linux
http://www.ati.com/products/pc/aiwradeon/index.html
Gatos
ATI All-In-Wonder Capture / Display Card Linux Drivers
http://gatos.sourceforge.net/
nVidia GeForce II
TV out drivers for Linux
http://sourceforge.net/projects/nv-tv-out/
http://www.nvidia.com/
Pinnacle Systems MP10.
http://www.pinnaclesys.com/support/products/info/default.asp?ProductID=308
This page has an interesting table that says that maximum image quality for a 352 x 240 pixel NTSC MPEG 1 is 3 Mbps, good quality 2400 Kbps, and so on trading off bandwidth for image quality. The slowest setting supported on the MP10 is 176 x 112 pixels (presumably at a 30cps frame rate) with a band width of 256Kbps.
http://www.pinnaclesys.com/support/studio/mp10/recequip.html
Xfree86
I am not sure about the price and availability of these cards. The All-In-Wonder PRO appears to be supported by Xfree86 but I am not sure about the newer 128 based on the RAGE accelerator chip.
http://www.xfree86.org/cardlist.html
Simple Directmedia Layer Library
Tony suggest that X windows is probably not the way to go for optimum speed maybe some Multimedia interface like SDLlib may suport. Simple DirectMedia Layer Library is an interface for a variety of Media devices for Linux. I am not sure if it supports Video capture cards, but I think it must if it is serious. It looks like this package runs on Linux, BeOS, Windows and Macs which is good for cross platform support.
http://www.libsdl.org/
Thoughts on MPEG
11th August 2001 7:48pm AEST Errrr Huston .... we have a problem ....
Although the download band width of cable is good .... 1 Mbps, the upload bandwidth according to Tony is
around 128Kbps, which is not so good. Video conferencing works over a 56Kbps modem, and in some cases
a lot slower than that. So I guess that is not a real problem, we just have to remember we are talking about
video conferencing bandwidths ... Not MPEG1 or MPEG2 quality at 25 cps or 30cps frame rate.
Maybe I need to find out if MPEG2 supports scalable bandwidths, frame rates and image resolutions.
There does not seem to be any advantage in using video cards that support MPEG1 or MPEG2 if the codec uses
a different algorithm. Also there is the issue of video formats. A video conferencing standard like H323 or CU30
elimates the need for scan rate conversion. MPEG seems to be formated to support NTSC or PAL however
with video conferencing, the output is done by the video card at the receiving end hence no US/Australia format
problems.
Other Odds and Ends
Here are some other Links that may be of interest:
http://linuxtv.openprojects.net/
http://www.linuxtv.org/
Multimedia 4 Linux
In German
http://www.multimedia4linux.de/