DavidTimms/DVB

Digital Television in Fedora

This page provides information on setting up a Fedora based system to operate with Video Broadcasting (DVB) tuner hardware, so that television programs can be viewed.

Introduction

In the majority of countries of the world, television stations now transmit digital television signals. While different digital transmission systems have been created, this document is about devices and viewers using the [DVB] standard.

By adding a DVB compliant TV tuner to a PC, a Fedora PC will be able to tune these channels. There is however, some setup of hardware, drivers, and application software required so that the full range of tuning channels, recording, watching and manipulation of off-air TV channels can be enjoyed.

DVB playback
The encoding scheme used in most digital television system is either MPEG 2 or MPEG 4. Since the Fedora distribution is based in a country where MPEG patents are recognized, it is not possible to play back DVB TV channels using only Fedora software. This guide shows how to use an external software repository (RPM Fusion) to provide pre-compiled software for the actual TV playback.

Hardware Setup

There are at least three major types of DVB tuner: [PCI], [USB] and [FireWire]. Your choice about which type to use should depend on things like do I:

• have a PCI slot available ? (-> PCI)
• have a USB port available ? (-> USB)
• have a FireWire port available ? (-> Firewire)
• mind opening my PC up ? (-> PCI)
• want to be able to use the tuner on different PCs ? (-> USB, maybe Firewire)
• want it to be portable ? (-> USB)
• want it to be a clean installation ? (-> PCI)
• some notebook PCs might come with a miniPCI or USB tuner built-in.

A good starting point for determining if specific hardware will work with Linux is the hardware page at Mythtv.org.

In all cases, a good antenna signal, and lead-in antenna cable will be required to plug into the RF antenna socket of the device; "rabbit ears" antennas might work in an area of excellent TV signal coverage.

PCI

Use the manufacturer's instructions to install the card into the system. When Fedora is booted, attempt to locate the device using

lspci |grep Multimedia

Find out more information by using the pci identifier listed in the previous result:

lspci -v -s 01:09.0

With luck this includes a line indicating the kernel driver in use and the kernel module loaded that is handling the device, eg. bttv.

USB

Start a terminal session and

su -c 'tail -f /var/log/messages'

Plug the tuner device into the machine. In the terminal some information about detection of the USB hotplug event and perhaps some firmware and or driver loading activity will be seen. Use lsusb to determine which usb ID is the TV tuner device, and then use lsusb -v to determine more information about that device.

FireWire

(To be improved ;-) Need information on how this stuff works with FireWire.

Firmware

Some devices require the machine that they are plugged into to download the firmware into the device before the device can begin to work. Firmware for some devices might:

• be included inside the device; the device just works
• already be packaged as part of the kernel-firmware package (this is true for some of the Hauppauge cards)
• be available as an internal something-firmware package within the Fedora software repository
• be available outside Fedora, but already packaged as an RPM
• be available as some other archive (perhaps the windows driver disk), that needs to be manually extracted and placed in the appropriate place

Various pieces of technology can assist with loading the device firmware. However, this relies on users reporting the steps needed to be taken to enable specific hardware. This includes getting information on lsusb/lspci device tables, HAL event triggers, and PackageKit software installation triggers.

Driver

All devices require a series of drivers to enable their capabilities. There will be a hardware specific driver e.g. dvb_bt8xx, pvrusb2. This driver is sometimes an external kernel module, but it might have been accepted to be a part of the kernel proper.

If the driver is already loaded, it may have been shown in the earlier lspci status example. If the driver is not loaded automatically, it will be necessary to read the manufacturer's instructions, web site, or web search to determine how to proceed.

If a driver makes it into the kernel-firmware package, it can then be trigger to load automatically when a device that it is known to require it is detected.

DVBv5 utilities

All the DVB drivers make use of the kernel DVB subsystem module dvb_core. There are user tools to work with the [1] subsystem. They are found in the v4l-utils package using DNF:

dnf install v4l-utils dtv-scan-tables

To see what tools are installed by the above:

rpm -ql v4l-utils

Use these tools to confirm correct detection and operation of the DVB subsystem using the following tools.

Initial tuning data file

/usr/share/dvbv5/dvb-t/country-location: provides an initial-tuning-data-file for a specific country-location. If available for your area the time taken to scan for channels will be much shorter (. however if one is not available for your location, auto-country or auto-Default can scan a large list of standard frequencies.

dvbv5-scan

Scan for all channels on all transponders (carriers) present in the the initial tuning data file, and creates dvb_channel.conf in the current folder e.g.:

dvbv5-scan /usr/share/dvbv5/dvb-t/au-Coonabarabran
ls -l dvb_channel.conf

Note: An existing dvb_channel.conf would be overwritten by this command.

Review the detected channels using a text editor:

gedit dvb_channel.conf

w_scan

If there is no initial tuning file for your area, you can use w_scan to for providers. For the -c option use your country code:

dnf install w_scan
w_scan -X -c au
... wait 10 minutes.

If this is successful, please send the created file upstream to the dvb-apps authors.

Xzap

Uses the channels.conf to tune the frontend to a specific transponder (carrier) and demultiplex the particular channel. The preceding X represents either ATSC, Cable, Satellite, or Terrestrial.

tzap -c ~/.xine/channels.conf -r "channelname"

A status line is shown indicating information such as signal strength, bit error rate and so on. It is updated once each second.

dvb-fe-tool

Show the capabilities of the DVB tuner hardware:

dvb-fe-tool

Press [control-c] to finish monitoring.

Monitor the DVB tuner hardware providing signal, carrier to noise, and post-correction bit error rate (more interesting if a channel has been zapped):

dvb-fe-tool --femon

Press [control-c] to finish monitoring.

lowlevel recording of a digital TV station

Once a Xzap has tuned a station, another terminal window can be used to record DVB channel (aka MPEG2 Program Stream), to a file:

cat /dev/dvb/adapterX/dvr0 >/mediastoragepath/programname.datetime.mpg

Once that has run for a minute or so, press [control-c] to terminate the concatenation. The stream can then be viewed using any mpeg2 video decoding software.

DVB Application Software

Live TV playback

There are various mpeg2 playback software available for Fedora, none of which are available in Fedora's own repos. Use an external rpm repository like RPM Fusion, by first enabling the repository. Since you will probably like to examine a few different applications to determine which is the most suitable for your needs:

yum install mplayer-gui xine gstreamer-plugins-ugly w_scan dvbcut

... please provide some simple usage information if you know how ;-)

The "ABC TV" name must exactly match the channel name in your channels.conf file.

mplayer dvb://"ABC TV"
xine dvb://ABC TV

Recording and scheduled recordings

yum install vdr-femon klear

... please provide some simple usage information / page if you know how ;-)

Full TV / media recording and playback suite

yum install mythtv-suite

... please provide some simple usage information / page if you know how ;-)

An alternate method could be using the Fedora-based MythTV distribution known as Mythdora. In either case, MythTV brings together a number of features/functions into what is generally known as a home theater server. MythTV features can include (assuming proper hardware, subscriptions, and/or plugins):

• Viewing of live television
• Automated recordings of shows based on search terms (show, title, date/time, actor or character name, etc.)
• Playback on your computer, a remote computer, or to a television
• Playback of locally (or remotely) stored media (audio and/or video)
• Playback of Internet streams (audio and/or video)
• Streaming of media (audio and/or video) to other devices or services
• Clustering of MythTV services on multiple devices
• Announcement of incoming calls
• The local weather conditions/forecast
• A web interface for scheduling and playback of recordings
• A slide show of stored pictures
• A SqueezeCenter interface
• A SIP interface (think Asterisk!)
• Themes and skins for the front end, backend, and some remote players
• and much more

Updates

We hope this has been useful in getting your DVB hardware working with Fedora. In any case feel free to update text on this page or link to other references if you feel they would have helped you get your tuner going more easily ;-)

Note: after review, this will possibly have links to [external software repositories] [removed].

Sources/Further Reading

• The MythTV web site
• The Mythdora web site
• The MythPVR web site

• LinuxTV wiki especially:
• Missing AC-3 audio streams. Note: in the second step, change dvbscan -c to scandvb -c.