Closed Captioning MPEG Video

Most Common MPEG Format? MPEG-2 Elementary and Program Streams MPEG-2 Transport Streams CableLabs spec 720x512 MPEG-2 for DG Fast Channel DVD Video MPEG-1 MPEG-4

---

We are often asked how to add closed captions to MPEG video files using CPC's MacCaption and CaptionMaker closed captioning software.  The answer is a bit complicated because there are many different kinds of MPEG files, and also different specifications for how closed captions can be embedded into them.  This page will list the common types and how to closed caption them.

Please note that CPC software does not convert other kinds of video files to MPEG-2 or change one kind of MPEG-2 file into another.  You need to use compression or transcoding software to first create the MPEG-2 file in the proper format, then add closed captions to it.

Most Common MPEG Format?

Sometimes we are asked "My client says they need a MPEG-2 file but they don't have any specific details.  What is the most common format used?"  In our experience, the format most commonly requested for DTV broadcasts is CEA-708 + CEA-608 (this combination is sometimes referred to as SCTE-43) closed captions in a MPEG-2 Program or Transport stream.  However, just because this is the most common format, does not mean that it will work for all uses.  For example, some providers may ask for a different combination of closed caption types (e.g. CEA-608 + SCTE-20) for standard definition MPEG-2 videos.

Closed Captioning MPEG-2 Elementary and Program Streams:

MacCaption DTV and HD Enterprise can add the following types of closed captions to MPEG-2 elementary (video) and program streams:

• CEA-708 (also known as DTV or HD closed captions)
  Note: Files encoded with CEA-708 must also include CEA-608 for backwards compatibility.
• CEA-608 (also known as standard definition or VBI "line 21" closed captions)
• SCTE-20 (required for SD video on some cable networks)

MacCaption can simultaneously encode any combination of these caption types, which can be selected in the Caption > Encode Preferences menu, and then exported via the File > Export > ATSC DTV 608/708 closed captions menu. 

 

Other export formats supported by MacCaption are:

• DVD-style closed captions (used by some devices)
• CCube/LSI DVx 608 closed captions (temporal or linear)

CaptionMaker HD Enterprise can also encode CEA-608 and CEA-708 closed captions in MPEG-2 elementary and program streams.

Closed Captioning MPEG-2 Transport Streams:

To add closed captions to a MPEG-2 transport stream, multiplexer software is required in addition to MacCaption.  If one of Manzanita's multiplexers is installed, MacCaption can automatically invoke it during the encode process to generate a closed captioned MPEG-2 transport stream.  MacCaption allows the captioner to specify the video/audio stream PIDs and a Manzanita config file, if required.

If you do not have Manzanita but do have another program to multiplex transport streams, you can add closed captions to a MPEG-2 elementary video stream, and then by using the 3rd party multiplexer software, combine the closed captioned video stream with the audio stream to generate a transport stream.

Closed Captioning CableLabs Spec files:

Comcast and some other VOD and cable providers require MPEG-2 encoded in the CableLabs spec.  This is a special kind of transport stream which meets strict specifications.  First you need to encode your video to a CableLabs-compliant MPEG-2 transport stream, using a tool such as Episode Pro, Rhozet, Digital Rapids, etc.. MacCaption then works together with Manzanita's multiplexers to add closed captions to the existing CableLabs-compliant MPEG-2 transport stream.

Closed Captioning 720x512 MPEG-2 for DG Fast Channel:

We have a special page that describes how to add closed captions to a 720x512 MPEG-2 video file, typically used by DG Fast Channel and some other networks for standard definition commercial spots.

Closed Captioning DVD Video:

Closed captions are usually not inserted directly into the MPEG-2 video for authoring DVD video discs.  Instead, a .SCC file is loaded into the DVD authoring program.  MacCaption and CaptionMaker can export .SCC files, and most professional DVD authoring programs can import them.  For more information, please see our Closed Captioning for DVD page.

Closed Captioning MPEG-1:

To our knowledge, there is no industry standard specification for adding closed captions to MPEG-1 files.  The user data packets where closed captions are stored are designed only for MPEG-2 files.  MPEG-1 files are still sometimes used by captioners as proxy movies for transcription or caption timing, but the finished closed captions are not added back into an MPEG-1 file.

Closed Captioning MPEG-4:

MPEG-4 (sometimes referred to as AVC or H.264) transport streams for broadcast can contain closed captions.  However this feature is not yet available in our software. Please stay tuned for updates.

MPEG-4 and H.264 QuickTime files for the web, podcasts, iTunes store, iPods & iPhones, etc. can be closed captioned using MacCaption.  This export is called the "QuickTime 608 Closed Captions track."  For more information, please see our Closed Captioning QuickTime for the Web page.