Closed Captioning Workflow
by Brandon Fenty on May 25, 2012 at 5:10:26 pm
I am trying to add Closed Captions to a project for CCTV, using compressor. Here's the output standards I'm told the TV should use:
MPEG2 Transport stream with AC3 audio
23.976 fps (use 3:2 pulldown if source is 29.97)
128 kb/s audio rate
I created a preset in Compressor to do this, ended up with a m2v and ac3 file, then used a freeware program called MPEG Streamclip to get a .ts file as the final output (the reference file that is known to work was also in this format).
I was concerned that I might lose the caption file when I used MPEG Streamclip to mux the audio and video, but I tested with VLC and captions appeared in the file with no problems. However, on the CCTV network, captions are not showing up whatsoever.
Is there something that I could be overlooking? When I view info for the reference file, it's nearly identical to the file I created (difference in resolution, reference file is 1080, but don't think that should matter for captions?)
Re: Closed Captioning Workflow by Jason Livingston on May 25, 2012 at 8:37:34 pm
There are several different methods for inserting closed captions into MPEG-2. VLC can read many of them, but the station might be looking for one of the other types.
Line 21 (although this would not work with your 23.976fps file)
Can you find out from the station which type they are looking for? (Did they give any specifics other than saying it must have closed captions?) Or can you get a sample from the station which includes CC that they are able to use?