Thursday, July 31, 2008

Audio Path for ABC, CBS, NBC, PBS

So I was looking for a price list on Dolby multichannel encoders, and came across this page. Dolby has PDFs available for ABC, CBS, NBC & PBS detailing the pathway the original feed takes from satellites through your local affiliate and finally into your HDTV. It is interesting to note that only NBC gives the local station the full uncompressed audio stream to all it's affiliates. ABC does give a nice 640Kb/s AC3 stream however, and CBS gives a Dolby E stream (a Dolby technology which encodes up to an 8 channel digital stream into 2 uncompressed audio channels). Now if only all the local stations could give Bozeman the surround sound goodness available in the source (KTVM excepted, of course).

Friday, July 18, 2008

Snapshots of Each Channel

So here are some snapshots from each channel I can receive, along with the program I recorded it during for the HD channels. For the SD channels I'm not actually sure what each program is, as I never really watch them :-). All of these images were taken from the original transport stream using VLC with the Linear deinterlace filter on. Without further adieu, here they are (be sure to click on each image to see it at full resolution)!

KBZK-DT CBS (Numb3rs)

KBZK-CW CW (Unknown, feel free to leave a comment with what the show is)



Thursday, July 17, 2008

OTA HDTV in Bozeman

In case you didn't know, I am a bit of a home theater aficionado. While I am also a college student with no money, I have assembled a reasonable quality system using my computer as it's foundation. One way I introduce new new media into the system is through Over-The-Air (OTA) HDTV signals. The standard via which you recieve these signals is called ATSC.

As I am going to school at Montana State University in Bozeman, Montana, I unfortunately do not have the same sort of selection of HD channels that I would have back in Seattle. Fortunately though there is still some high-definition material on the airwaves. Below is a chart comparing each channel.

Bozeman HDTV Summary
NameTypeChannelProgramRes.ProgressiveDolby 5.1?Bitrate (Mb/s)

The bitrate readings were taken using TSReader Lite over a 5 minute period.

Important to me is the fact that only KTVM, our NBC affiliate, has audio in 5.1 Dolby. The rest have Dolby Surround compatible 2 channel downmixes. From what I have heard from the broadcast engineers, this is because of EBS regulations, and a lack of funds to purchase the required 5.1 Dolby encoder.

In terms of HD material, the KUSM-HD has beautiful HD material on the air 99% of the time. If I ever need to show someone how good HD can look, usually I'll pull them up.

None of the channels have local news in high definition, though anything that is on primetime usually is broadcast in HD.

You may be wondering where ABC & Fox are. The reason for their absense is the fact that they are not broadcasting digital signals yet, and are not expected to until the cutoff date. More worrying is the fact that even in Billings, where they are being broadcast digitally, neither one is in high definition. I intend to contact each of them and find out what their plans are for broadcasting digitally after the cutoff date.

Well there is a quick rundown of the different Over-The-Air digital options for Bozeman, Montana.

Edit: when I get a chance, I'll upload images of each channel during primetime.
Edit2: Woohoo! I got past Blogger's attempts to screw up my table.


So late last year I needed a way to view OTA HD broadcasts. I searched around, and while I originally was thinking about purchasing a PCI or USB based capture device, a friend mentioned that he had been looking at the SiliconDust HDHomeRun device.

Essentially the HDHomeRun is an ATSC/QAM tuner with an Ethernet output. The device connects to an over the air antenna or unencrypted cable coax jack and then sends beautiful MPEG2 signals across your home network. They have a rather primitive Config tool for windows to allow you to look up and view channels, but to really use the device you should connect it to MythTV, BeyondTV, or some other computer based DVR program (I personally use MythTV and highly recommend it).

Next post: a review of the Over-The-Air Digital signals in my area!