from the Introduction page:
is giving a not found. I would like the specifications for 333ksps RBTV in terms of recommended image size, FEC, codec etc. (as might others seeing this free download for non-members - finding it through Google).
I've updated the link on that post - it now points to the font of all knowledge - the BATC wiki!
https://wiki.batc.org.uk/Getting_Starte ... ndwidth_TV
Typically we run 333Ks (~500KHz) down to 65 Ks., 7/8 FEC and H264 / H 265.
Noel - G8GTZ
In Portsdown the transmitted image size and frame rate depends on the Video bitrate. Simplified code:
Code: Select all
# Reduce video resolution at low bit rates if [ "$BITRATE_VIDEO" -lt 150000 ]; then VIDEO_WIDTH=160 VIDEO_HEIGHT=140 else if [ "$BITRATE_VIDEO" -lt 300000 ]; then VIDEO_WIDTH=352 VIDEO_HEIGHT=288 else VIDEO_WIDTH=720 VIDEO_HEIGHT=$IMAGE_HEIGHT fi fi # Reduce frame rate at low bit rates if [ "$BITRATE_VIDEO" -lt 300000 ]; then VIDEO_FPS=15 fi
The beauty of MiniTioune is that it is flexible enough to receive and display all these modes.
OK, I see what you mean. So, the software (either DATV Express/Win-10/Pluto) will resample the input stream to those dimensions before transmission. I didn't appreciate it did that. But why the non-standard aspect ratios, or are those simply max-width and max-height limits?
I also note that on the DATV Express/Win-10 software, on the Video Codec dialog, there is a fixed video bitrate number displayed (e.g. 275495), but also an option setting at the bottom of the dialog currently set to 0.7 but also labelled video bitrate. Is this a k-factor setting or something else? It would help if these values and labels had mouse-over hints saying what they do. I find these can reduce support effort!
Unfortunately the SDRangel software I'm using for tests only has DVB-S, but I do have a MiniTiouner Express installed and working for later tests.
I must admit to inheriting those image sizes with the original code and never checking or changing them. Some of the odd aspect ratios are because the hardware H264 encoder needs the horizontal image size to be divisible by 32 and the vertical to be divisible by 16.
I am not an expert in the DATV Express software - just an occasional user. Charles should be able to help.
There is a big push for some SDR software to support DVB-S2 for Es'hail-2, but there is a lot of work to be done. F4DAV is making some progress.