Closed captions with Mpeg2

PatMorten wrote on 11/26/2013, 2:06 PM

My workflow is:
Create a 720x480 project.
Import an avi file (720x480) without closed captions, generated by another program.
Import a .scc caption file, generated by another program.
Video and captions work fine on the timeline. I can view them on the program monitor.
Then I need to render to a 720x480 Mpeg2 program stream file. When I review the file with VLC player, the captions don't show up on the resulting file,.
I have also made a custom template at 720x486, as that seems to be the frame size needed for broadcast captions, but I get an error message saying "An error occurred while creating the file. The reason for the error could not be determined."
I am able to successfully render to an mxf file, but my broadcaster is requiring mpeg2.
Anyone else face this situation?

Comments

larry-peter wrote on 11/26/2013, 3:25 PM

I have only found a few (very expensive) solutions to directly render CC into an NTSC compatible MPEG2. The only solution I know of within Vegas is to create a 720 X 512 MPEG 2 which includes the additional blanking and lines that contain the CC. Most broadcasters, including DG and other content providers can use this size MPEG2.

To do this within Vegas means rendering an uncompressed 720X 486 AVI with embedded line 21 CC, then importing this into a 720 X 512 project with a positioning offset (one that I worked with a station for quite a while to determine) and then rendering a 720 X 512 MPEG2.

If this looks like a workflow that would work for you and the station, I can give you the details of how my timelines are set up to render the MPEG2s and then to bring them back into Vegas to check that line 21 is properly encoded. It's a pain, and I wish Vegas would not stop at the "half-you know what" solution we have now, and make it possible to do a complete CC for broadcast workflow.

Also, I have an AJA Kona card which delivers both SDI and component signals to an SD broadcast monitor. If you're using a secondary monitor for preview, I'm not certain you would be getting line 21 info read correctly for proper QC. You can't trust the Vegas monitor for this. It is reading the embedded markers, not line 21.

PatMorten wrote on 11/27/2013, 12:47 PM

Thanks for the reply.

I have received further information from the broadcaster, which I am trying out now.

PatMorten wrote on 12/13/2013, 9:40 AM

Again, thanks for your reply.

Here is, in short, what I have found from my broadcaster.

The base template was for DVD Architect, which is set to 720x480. The customized settings they sent me were only for picture quality, really. I sent them the file with the captions embedded, and it works for them. From what I have read on the topic, it probably isn't line 21, but they are able to work with it anyway.