DStar TV - FAQ

DStar TV

DStar TV FAQ

1) What is DStar TV ?

In its simplest terms, DStar TV is Slowscan TV for DStar digital radios.

2) Why not call it DStar SSTV then ?

Bit of a mouthful that....

3) What can I do with it then ?

You can send pictures using the digital data stream on a DStar radio, either by loading a picture from a file on your PC or capturing an image from a Webcam (or any video capture device, TV card etc)

4) Won't it be a bit slow sending images at 1200bit/s ?

In a word yes, however, DStar TV sends images as a compressed jpeg (240x240 pixels), the compression can be adjusted, i.e. higher the compression, lower the quality, faster the transfer, obviously the converse is true. Remember, this is on par with slowscan TV, and as such has about the same transfer rate.

5) What operating system do I need to run it ?

DStar TV runs on windows XP,Vista & Windows 7 and requires .NET 3.5 framework to be installed before it'll run.(not required for windows 7) (see the download page for information). I've not tested it with windows 2000 or Linux (using mono), it may work, although I'd be surprised if it does.

6) What hardware do I need ?

A relatively speedy pc is ideal but I've managed to run it happily on my eee pc701 runs a celeron @ 633mhz and 1gb ram. You will also need a dstar radio, a free com port and (optionally) a webcam or video capture device.

7) My PC doesn't have a com port! Can I use a usb to serial adaptor ?

Yes, I've tested it with a few USB to Serial port adaptors, however, make sure that use the prolific chipset as I've had issues with other types, obviously a proper com port is better.

8) What radios does it work with ?

I've only tested it with my IC-E2820 and V82 handheld, works fine with both of those. Best thing is to try it with your radio and post results in the forum

9) What webcams does it work with

I've tried various logitech and creative cams, all work, as does the eee pc cam. My TV card works as well. Its best to simply try your cam and see what happens, if it doesn't work then post comments in the forum.

10) When I click on Webcam, my webcam toolbox appears !

That's generally normal, calling the webcam driver initiates this and there's not a lot I can do about it, however, you can use the various effects available to you (I can put an arrow through my head with my logitech cam!)

11) How do I save the image I received ?

File > Save

12) It hung/crashed on me!

It'll do that. Its currently in beta, I expect ~~many~~ some bugs.

13) How much does it cost to register

Its freeware, so nothing and will always be freeware, in the spirt of amateur radio. Its NOT open source (yet) however, but the transfer protocol will be.

14) What are the modes ?

Broadcast is the default mode,i.e. one to many, like standard sstv. There is no error correction and data corruption is a possibility.
Targeted is one to one, i.e. you connect with another callsign and transfer the image with error checking.
Repeater, as it sounds, will receive and forward images.

15) How does Broadcast mode work ?

Load an image, click RADIO > CONNECT (or double click the red DISCONNECTED label at the bottom of the window till it turns green). Click SEND!

The header is sent first, this contains your callsign and the filesize. Next is the image converted into Base64 binary. When its finished sending the image the end of file is sent (*eof*). Base64 is used as the DStar radio's can't seem to handle binary data properly so it has to be encoded in a simple format. Base64 increases the filesize from the original jpeg image.

16) How does Targeted mode work?

Firstly, ensure you have setup the following : Tools > Options > Targeted. In blocksize, set a number between 8 and 2048 (I suggest 128). This is the number of bytes send during each block transfer. The TX/RX delay is the length of time (in milliseconds) for the radio to change over.(I found 2000ms was pretty got for the IC-2820, I needed longer (2200ms) for my IC -V82. Adding a linear amplifier will require this to be even longer). There is a random number also added to this time during each over to prevent packet collision during negation.

Click ok to close the Options dialog. Next on the main window select a callsign from the heard list or enter a callsign into the "connect to" box. Click Radio > Connect. Load an image or switch on the webcam. When your ready to go, click SEND.

The receiving station will automatically go into Targeted mode and start the negotiation. If it fails to "hear" you, it'll timeout after 6 retries. Keep an eye on the data monitor, it'll give you an indication of what's happening. When a CONNECT OK is received, the blocksize and number of blocks are transmitted with the return of BZ OK and BC OK. The blocks are now transmitted. Each block contains a crc16 checksum. If the block is received ok, an OK. is returned or if it detects a crc error, an ERR is returned and the same block is retransmitted. This will happen 6 times before the sending station gives up.

If the receiving station is reporting lots of crc errors (i.e. Checksum error 0A3A expected BBAE) try the following a) reduce the block size, b) increase the TX/RX Delay and/or Packet Delay. On the other hand, if everything is working well you can try reducing the delays to speed up transmission!

17) What is the beacon ?

Beacon has two modes, one sends a text beacon (will be used for targeted mode, see above) and the other mode is beacon image which sends the current image in broadcast mode. This could allow for unattended operation (cctv ?). You'll probably need an NOV for that in the UK.

18) I want x,y & z features!

Let me know in the forum!

19) Why does it "phone home" each time I run it ?

Its checking for updates, and don't worry, I don't collect any information. This should allow for everyone to be running on the same version as its likely I'll change the protocols it uses. It doesn't require to be connected to the internet to run however.

20) What is packet delay ?

This is the delay (in milliseconds) before the next packet of data is sent, too fast and the buffer on the radio overflows too slow and the transmission is choppy. Its best to experiment, PC speed also plays a factor in this.

21) My com port doesn't appear in the list available ?

When the program starts It checks for free com ports. If you don't see your com port then this means its a) In use with something else or b) Its set to be greater than COM24, to speed up loading the software only checks COM1 to COM24. To solve this check your com port isn't in use and its set to less than COM24.

22) I got the error "Com port changed", what does that mean ?

The com port you set previously is no longer available (unplugged or in use). The software will default to the first available port.

23) I got the error "no com ports" and the program closed ?

The software (currently) needs a com port to talk to the radio. This may change. (If someone wants to send a me a free Icom ID-1 to test using the ethernet port!)

24 How do I use the ID-1 video streaming ?

Firstly you need an Icom ID-1. The software uses DD mode not DV mode for streaming video and this is available on the Icom ID-1.

Before starting you need to give the software some information on your setup (see below)

IP Address (to connect to, this is set on the main window)

Loopback. Checking this will change the ip address to 127.0.0.1. This is useful to check your own video after compression etc.

Select the video device you intend to use, this can be the same as the webcam you can use for DV slowscan mode.

Select the video size. (smaller = faster, larger = slower)

Audio input device. This is for sending speech etc, currently the audio doesn't work properly, it uses to much bandwidth. I'm working on way to reduce this.

Audio output device. Soundcard used for audio playback.

Video recording codec. This is the codec used for video compression when recording the video stream.

Audio codec. Codec use for streaming audio.

Compression. More compressed, faster the video. Higher the number the greater the compression

Keyframe interval. Only the changes between frames are sent. To reduce CPU usage etc on slower PC's increase this otherwise keep it set at 1.

Autoconnect. Checking this will allow stations to automatically connect to you, unchecking will prompt you to accept connections.

Stream Audio. Audio streaming doesn't work properly at the moment, best to keep this unchecked.

ID1 control. DStar TV can control the ID-1. Certain functions aren't implemented (they arent really needed, like memory channel programming etc). You can still operate the radio using the RC-24. changes on its display are reflected on the software. Please ensure you have chosen the correct COM port for the ID-1 in the comms tab!

Auto TXinhibit. On streaming or connecting the software will disable the txinhibit. When the software is idle (i.e. not streaming or connecting) it will enable the txinhibt and stop data being broadcast. This is useful to prevent general windows traffic being broadcast.

Firewalls. You must allow ports 9990 and 9991 to pass through your firewall, or disable the firewall on the ethernet connection which the ID-1 uses.

25) Using the ID-1 Video.

When you've set options above, click ok. Then click Mode > ID-1 Vidoe (or the button ID-1 Video)

The software will attempt to power on the radio. If it fails you'll get an error message to this effect, if you have id-1 control disabled then you should load up anyway. At the end of initialising the radio you should be presented a screen similar to below :

Its fairly straightforward. The frequency and various other indicators are displayed in the orange panel, including a S-meter.

To change frequency enter the frequency required in the box and click "tune" or to step up or down press the arrow buttons. To change the step size click the step drop down box.

IP Address : this is the ip address of the station you wish to connect to. You must know this in advance.

To connect, click Connect. If all is well you should receive an image in the receive box, and the heard list should be updated with the callsign of the station you are connected to.

To record the video being received click "Record" and "Stop Recording" to stop. To capture a still image, click Capture.

To Stream your own video click "Stream".

26) In the screenshots (and image preview mode), what are the cats called ?

Chocolate milk and Sugar ! My cats who frequently help (!) with the coding ;-)