The latest FCC requirements raise the bar for closed captioning for broadcasters and cable operators. FCC Title 47 went into effect on March 16, 2015, ensuring that viewers who are deaf or hard of hearing have full access to pre-recorded, live and near-live programming.
These rules established a requirement for recordkeeping and a procedure for handling formal complaints, but there were no specific metrics or standards listed for measuring compliance. The rules only describe best practices and the core requirements. Per the rules, closed captions much meet the following criteria:
Accurate: Captions must match the spoken words in the dialogue and convey background noises and other sounds to the fullest extent possible.
Synchronous: Captions must coincide with their corresponding spoken words and sounds to the greatest extent possible and must be displayed on the screen at a speed that can be read by viewers.
Complete: Captions must run from the beginning to the end of the program to the fullest extent possible.
Properly placed: Captions should not block other important visual content on the screen, overlap one another, or run off the edge of the video screen.
For content distributors, FCC enforcement of the new rules will typically happen at the transmission point. Broadcasters and cable operators now also have a tighter mandate for ensuring locally produced content is captioned correctly in addition to syndicated and network content.
There are any number of things that can go wrong with closed captioning, including no captions present, captions appearing at the wrong time and captions not ordered correctly to name a few. Let’s look at the various steps in the workflow and some examples of how errors get introduced.
In some cases, timecodes can be set incorrectly during caption creation resulting in captions that will be out of time or never get inserted. Typically this stems from a caption inserter being configured with wrong settings (e.g. 1080p for a 1080i file). The result is that most caption decoders and set-top boxes will show scrambled captions
During content acquisition, a common problem is incorrect formatting of 1080 to 720 conversion. As a rule, if the program is 1080i but the transmission format it 720p, you have to repackage the captions with new headers in order to maintain the correct baud rate. The result of this error is that most caption decoders will show scrambled captions.
Along the path from file ingest to play-out server captions can be dropped due to incorrect settings that lead to a failure to capture caption data. Data hits can also lead to caption packet errors that cause most caption decoders to show scrambled captions. Problems can also occur during network playout. A common one is incorrect setting of network components again leading to dropped or mangled caption data and scrambled captions.
Given the broad potential for problems, errors and complaints are inevitable to some degree. When complaints happen, first check to see if you can reproduce the error from either the customer’s point of view or from a test point at the output of the system. If you can duplicate the error, go to a midway point in your system to see if the caption error continues. As you troubleshoot the caption error you may need to look at several types of media within your system including QAM, IP, files and SDI. It’s important to have the proper monitoring and analysis tools to look at these different types of media at various points on your network.
There are a number of closed captioning monitoring and analysis tools available for broadcasters and cable operators, and should be included in the mix to help ensure compliance.
Real-time monitors provide the ability to monitor, alert and report on the availability and quality of closed captions across all channels in real-time. If captions are in error, you need to know the percent of time they were in error and why. Depending on the size of the network, it’s helpful to understand if errors are occurring on a local, regional or national level to highlight the cause.
In the file domain, file-based monitoring tools should at a minimum verify that 608 and 708 captions are still intact. More advanced tools can perform over 30 types of syntax and structure checks to ensure that the data has not been corrupted during the transcode process. Some examples of these include illegal characters in 608 data, caption windows overlapping and incorrect caption data ordering.
A waveform monitor can also be useful for troubleshooting. For instance, it provides the ability to view both 608 and 708 captions at the same time and can quickly identify times when text is out of sync with the video. It can also confirm caption data pack length and that service counts are the same in 608 and 708 captions.
The final resolution of the new closed caption rules will be determined by the viewer and whether they are annoyed enough to file a complaint. The reason the FCC never identified a compliance rule is that caption decoders’ capabilities vary greatly between consumer devices. Some devices just do what the standard says, while others will try to show some bad captions on the screen. As such, it’s imperative that broadcasters have all the essential tools in place to make sure the captions are compliant with the FCC’s new best practice rules.
Steve Holmes is a Senior Video Applications Engineer at Tektronix.
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