Digital Video Broadcasting – Terrestrial


DVB-T is an abbreviation for "Digital Video Broadcasting — Terrestrial"; it is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in the UK in 1998. This system transmits compressed digital audio, digital video and other data in an MPEG transport stream, using coded orthogonal frequency-division multiplexing (COFDM or OFDM) modulation. It is also the format widely used worldwide (including North America) for Electronic News Gathering for transmission of video and audio from a mobile newsgathering vehicle to a central receive point. [1]


FOr the test we implemented a flowgraph. This flowgraph uses the SDR boards, which were provided, for the communication. [3]


The flowgraph used for the test can be downloaded here: dvbt_tx.grc


FFmpeg is an open-source video and audio transformation tool, which was uesd to convert an arbitrary input video into a DVB-T compliant vido stream.

Usage for DVB-T conform conversion

ffmpeg -i <input_file> -vcodec mpeg2video -s 1020x1080 -r 29.97 -b:v 24M -minrate:v 24M -maxrate:v 24M -bufsize:v 1.4M -acodec mp2 -ac 2 -b:a 192k -t 60 -f mpegts outfile.ts

Description of Used Options

The options used for the convertion are described in this chapter. [2]

sets the videocodec. For DVB-T the MPEG-2 (mpeg2video) codec is used. MPEG-2 is a lossy video compression and lossy audio compression standard.
sets the frame size
sets the frame rate
sets the average video bitrate
sets the minimum bitrate tolerance to be used
sets the maximum bitrate tolerance
sets the audio codec
sets the number of audio channels.
sets the audio bitrate
limits the duration of data read from the input file in seconds
sets the output file format. MPEG-TS is a container format for transmission and storage of audio and vido. MPEG-TS was designed for less reliable transmission such as terrestrial or satellite broadcast. The container format encapsulates packets of an elementary audio and video stream with error correction and synchronization features for maintaining transmission quality when the communication channel carrying the stream is degraded.

Available bit rates (Mbit/s) for a DVB-T system in 8 MHz channels

This chapter shows a table with the available bit rates for the DVB - T transmission. [1]

Modulation Coderate Guard Interval
1/4 1/8 1/16 1/32
64-QAM 1/2 14,929 16,588 17,564 18,096
2/3 19,906 22,118 23,419 24,128
3/4 22,394 24,882 26,346 27,144
5/6 24,882 27,647 29,273 30,160
7/8 26,126 29,029 30,737 31,668