SpiceWare's Blog

added TV Guide app info

Just so info about channels & subchannels. First, each channel has a physical channel number (frequency) and a virtual channel number (the number you select). This is because as part of the analog to digital change stations were assigned different frequencies (physical channel), but stations wanted to keep using the same channel number. (i.e. KPRC 2 while it's actually on channel 51) This is why you have to scan for channels when you first receive your TV or HomeRun - so the tuner can visit each physical channel and pull the virtual channel out of the datastream. This can be a major challenge if you have a rotor.

 

Subchannels are basically independent audio & video streams embedded in the MPEG-2 transport stream encoded in the 19.39Mbps ATSC channel. Each program appears as a subchannel of the virtual channel and may be HD, SD or audio only. Although .1 is typically an HD channel this is not required.

I remember reading about the subchannels and physical/virtual channel numbers when I first got into HD 11+ years ago, but since I never had a tuner until now I'd forgotten about them as the providers I've had (Time Warner/Comcast at first, then later DirecTV) have only carried the .1 channels.

 

I didn't realize audio-only was possible, though I knew HD wasn't a requirement as when the conversion started Fox was doing "Enhanced Definition", widescreen at 480p, which looked quite poorly on my 65" set vs the other channels that were sending 720 and 1080.

 

Looks like Fox was trying to force adoption of the broadcast flag, which has thankfully been finally shot down else this project wouldn't be possible.

 

Do you have any knowledge of the encrypted channels? As seen in the 4th image the scan picked up 8 of them, but I haven't had time to look into what that's all about.

According to http://houstondtv.wordpress.com/dial and http://houstondtv.wordpress.com/tag/airbox the encrypted channels on 49 are part of the AirBox subscription service.

Thanks!

 

I hadn't heard of AirBox before, though that makes sense as they seem to be targeting hispanic viewers as they only offer The Latino Pack with optional Starz.