"NY" wrote in message
"Jeff Layman" wrote in message
According to A516digital, the update today was:
"Channel 788 - ITV3 (PSB2/D3&4) Duplicate of service on channel 10, but
with increased resolution."
Sorry for the ignorance, but what does this mean? Is it likely that other
stations will follow?
ITV3 (like Drama, Yesterday, Talking Pictures TV etc) is one of those
channels that broadcasts in sub-SD: 544x576 rather than 720x576 (ie 3/4 of
the normal horizontal resolution, rounded to the nearest 16-pixel
So maybe 788 is 720x576.
Yes, I've just run TSReader (Windows program) via my DVB-T decoder on mux
PSB2 and sure enough, 788 (ITV3) is 720x576. Looks as if LCN 10 is still
on mux COM4. I presume at some stage it will be switched off and the one
on PSB2 will become LCN 10.
On further analysis, the differences a
- 720x576 as opposed to 544x576 video
- Programme sound is 192 kbps rather than 128 kbps
- 720 version has a second audio description sound channel which the 544
- Video bit rate 2.03 Mbps as opposed to 1.72 Mbps
- File sizes (for identical 23m 17s clips) 393 MB as opposed to 319 MB
Theoretically, the 720 version should be 4/3 the file size of the 544
version because of the greater horizontal resolution, *assuming the same
amount of compression*. In fact the 720 version is only 1.23 instead of the
theoretical 1.33 times the size of the 544, so it looks as if the 720 is
compressed a bit more.
Here are identical stills, all scaled to a theoretical 16:9 display size of