05.01.2009 03:37 PM
Originally featured on BroadcastEngineering.com
Wohler HD closed-caption encoder supports industry protocols
Looking to help broadcasters handle FCC-mandated captioning data for both SD and HD content, Wohler Technologies offers its HDCC-200A HD/SD-SDI dual-channel closed-caption encoder/decoder bridge with support for both U.S. EIA-608/EIA-708 and OP47 protocols. The HDCC-200A simplifies closed-caption encoding of two independent SD and HD sources.
The HDCC-200A card encodes closed-caption data into SD Line 21 (EIA-608/NTSC) or directly into the DTVCC transport stream (EIA-708/ATSC) — encoding two independent sources with unique closed-caption data or, when the signal output is intended for use in different distribution, encoding two independent sources with identical data. Each of the card's channels has a “clean” output and a captioned output with a burnt-in, closed-caption display that enables easy monitoring.
The HDCC-200A formats the closed-caption data into the HD VANC and SD-SDI video stream, allowing for distribution or storage within a broadcast facility. New firmware, which made its debut at the 2009 NAB Show, allows the card to auto-sense the input format (NTSC, PAL, 720p, 1035i, 1080i, 1080p) and configures the internal encoders and decoders automatically, thus removing the need for user intervention. Crossconversion of caption data between formats of the same or higher frame rates is standard. Caption data from a 720p 24Hz signal can be crossconverted to a 1080i 60Hz signal seamlessly.
The proprietary GPI encoder/decoder allows the insertion of GPI data into the video stream simultaneously and can be used in a variety of applications that were traditionally set aside for “cue tones.” The advantages of the GPI interface include the virtual elimination of false triggering by the use of sophisticated error detection and frame-accurate encoding and decoding of GPI data. GPIs are not activated until they pass the stringent set of checks.