OTA -- Over the Air

to install:

$ ostv install_class ota

create a folder ostv in ~/recordings

$ mkdir ~/recordings/ostv

This is where ota/qam will be saved if backsaved(see backsave) or if recorded from the Schedule plugin.

prerequisites:

• A dvb device installed and setup.
• A channels.conf file in ~/.ostv/channels and ~/.mplayer(use a symbolic link)

dvb devices are pci cards or usb sticks that receive digital tv signals. They are often not explicitly referred to as dvb, but if they tune ATSC they are a dvb device.

The best resource for installing dvb devices is:

http://www.linuxtv.org/wiki/index.php/Main_Page

There is also info there about which dvb devices are supported by Linux and how to scan for your channels and create channels.conf (http://www.linuxtv.org/wiki/index.php/Scan).

Creating a channels.conf file

Here is a short course for USA users on how to scan and create your channels.conf file:

1. install the program dvb-utils or dvb-apps from your package manager. This program has different names in different distributions. In Ubuntu it's dvb-utils, most others it's dvb-apps.

This should be similar for users in other countries. There are many scan files in /usr/share/doc/dvb-utils/examples/scan/. Find the one for your location

at a command line prompt:

$ scan /usr/share/doc/dvb-utils/examples/scan/atsc/us-ATSC-center-frequencies-8VSB > ~/.ostv/channels/channels.conf
(note: your /usr...8VSB might be in a slightly different location)

warning! A scan can take 15 minutes or longer!

• You can edit the channels.conf to use whatever channel names you want and you can delete the lines of channels that you are not interested in
• Make the link for ~/.mplayer

$ ln -s ~/.ostv/channels/channels.conf ~/.mplayer/channels.conf

QAM

OSTV, by virtue of the OTA plugin, also supports unencrypted QAM or Cable TV. The unencrypted channels are usually limited to the basic tier and include what you can get over the air, CSPAN, local, weather, shopping and religious channels. Setting up QAM is identical to OTA, you just use a different scan file.

$ scan /usr/share/doc/dvb-utils/examples/scan/atsc/us-Cable-Standard-center-frequencies-QAM256 > ~/.ostv/channels.conf

If your dvb device has separate connections for OTA and QAM you can include both in your channels.conf

Troubleshooting QAM

QAM has the potential to be more problematic than OTA. If your scan does not return results, there are several other scan files for cable in /usr/share/doc/dvb-utils/examples/scan/atsc/ to try.

If you get messages such as

WARNING: filter timeout pid 0x0000

your channels.conf file will be generated but will need some work. This basically means scan found the channel but the data was incomplete.

Even if you did not get that message you may have the following problems:

• scan returned hundreds of channels

scan returned all your cable companies channels including encrypted channels and other extraneous data. A well formed scan line looks like this:

KOHD-HD:675000000:QAM_256:1984:1985:9

name :frequency:protocol:video pid:audio pid:qam channel

Your scan lines might look like this:

[00af]:675000000:QAM_256:0:0:1985:9

You need to go to your cable company's website and find some info. You might find a faq like "I want to access the 'free' channels with my TV's digital tuner" and find a listing with all the the QAM numbers. The QAM numbers usually are something like "37-9". OSTV only concerned with the part after the hyphen. If you do not find such a listing, go to the "channel lineup" page. The channel numbers often correspond to the qam channel value, but sometimes they do not. If you are left guessing you can try tuning channels or consult your cable company's tech dept. In your scan lines find where that number matches the last value. Those are the scan lines you want, delete the rest.

• Channel Name is [00af]

If scan could not find a name it returns a pid. The name value does not matter, you can put anything you want there. If it has the "[]" brackets it will not work though! Remove the brackets and put something meaningful there.

• Extra Values

This scan line has an extra value of "0"(it is always 0). This will happen sometimes--remove it! 6 colon separated values only.

• Video PID = 0

Another thing that happens is a video pid will have a "0" value. You will not get video with a "0". Usually the video pid is 1 less than the audio pid. In our example it is "1984". Replace the "0" with that value. If this doesn't work try replacing it 2 less than the audio pid.

Subtracting 1 or 2 should work. Should this fail, you can get your pids by tuning in the channel from OSTV and using the scan command line tool. Tune the channel by saving the scan line in channels.conf and tuning the channel in from the OSTV menu. Even if fails and doesn't show video, it will most often tune and be able to return data from the scan command. Power off OSTV, then at the command line:

$ scan -c

This will return several lines of data like this:

[000e]   (0x000e) 00: PCR == V   V 0x0800 A 0x0801

000e is pid created for the channel name when it can't find the channel name

0x000e is the QAM channel # in hex

0x0800 is the video pid in hex

0x0801 is the audio pid in hex

All the channels are returned for the frequency that was tuned in. To find the line you are concerned with translate the audio pid or the QAM channel number to hex. Those values will be on the line you are concerned with. Use your google search box to translate: you can also translate hex and decimal values using calculator programs

2049 in hex

The video pid is in hex and needs to be translated. To translate hex to decimal, again use your google search box:

0x0800 in decimal

That will give you your correct video pid.

Glitch After you edit your channels.conf file menus should be updated in the menu next time you restart OSTV. There is a gitch where this doesn't always happen. In that case at a command line: $ ostv ota then restart OSTV

Continue Installing OSTV at:

Installing OSTV part 3 More Plugins