Does EIA-708B standard supports MPEG4 Video for Closed Capti

santoshkp

DTVUSA Rookie
#1
Currently EIA-708B & EIA-608 standard was supported in MPEG2 video. But ,MPEG4 supports EIA-708B standard or not,i am not sure about this. Need Confirmation from you.we are following these standards for closed captioning.
 

santoshkp

DTVUSA Rookie
#3
This is regarding addtion of closed caption to MPEG4 video.

There is one standard(EIA-708/EIA-608) which we follow while adding the caption/text to the MPEG2 video.the same is possible for MPEG4 or not we are not sure.
 

Thomas G

Contributor
#4
Broadcast Engineering Article with no mention of MPEG-4...

EIA-708B captioning


Figure 1. An analog TV signal that contains CC 608 data is fed into an MPEG encoder and a closed caption extractor box, then to a CC receiver that converts the 608 data to 708 format. Click here to see an enlarged diagram.

As mentioned before, analog closed caption data is located in the VBI of the analog stream. Digital TV signals do not have a vertical blanking interval. The digital EIA-708B standard offers an alternate way of including existing analog closed captions in the digital signal by transcoding or converting EIA-608 data to the EIA 708 standard via a closed caption conversion box that can receive either format. This saves production houses and studios from having to reproduce existing closed caption data in 708 format from scratch. In Figure 1, an analog signal containing CC 608 data is simultaneously fed into an MPEG encoding board and a closed caption extractor box. The closed caption extractor separates the CC data from the composite signal and feeds it into a closed caption receiver for conversion to the 708 format. Meanwhile, the MPEG encoder compresses the composite TV signal into MPEG. The MPEG signal and the 708 data are then multiplexed and output as an MPEG-1 or MPEG-2 stream.

Today, most DTV content still relies on EIA-608 captions that have been converted to 708 format, mainly because of the small consumer base of DTV receivers. When a larger number of consumers have receivers that are able to receive DTV signals, there will be more pressure on producers and broadcasters to include native EIA-708 closed captions.

No time to waste
Given the regulatory pressure to produce new programming with digital closed captions based on the EIA-708B standard, producers and broadcasters should be seriously thinking how to make this move. Although investing in new equipment may involve a learning curve and a capital investment, there is no doubt that the end product, in terms of quality and benefits for consumers, will be superior to that available today.
 
Top