Tvsignalering

Tvsignalering, or television signaling, refers to the set of methods and data carried within television transmissions that allows receivers to identify, decode, and present the content and related services. It encompasses both the signaling used in traditional broadcast systems and the metadata and control information used in digital and IP-based delivery.

In the analog era, signaling included data carried in the vertical blanking interval, such as teletext, closed captions, program identifiers, and test signals. This data enabled receivers to display additional information and to verify transmission quality, even though the primary video and audio were carried separately.

Digital television relies on structured signaling to manage channels, programs, and services. In DVB-based systems, signaling is carried as SI/PSI (service information/program-specific information) tables within the MPEG-2 Transport Stream. Key tables include the Program Association Table (PAT) and Program Map Table (PMT) for program identification, Network Information Table (NIT) for network details, Service Description Table (SDT) for service descriptors, and Event Information Table (EIT) for schedules. Conditional access signaling (ECM/EMM) governs access control. In ATSC, the PSIP framework provides similar metadata. The signaling layer enables channel scanning, electronic program guides (EPG), subtitles, and accessibility features.

With the rise of IP-based and hybrid systems, signaling extends to IPTV and streaming, where manifests, such as MPEG-DASH or HLS playlists, describe available content, while metadata and CA-like data may be delivered alongside the stream.

Overall, tvsignalering coordinates channel discovery, service identification, program information, access control, and ancillary data to ensure correct reception and user-facing features.