Delivering 608 & 708 Captions (which Resolve doesn’t support)

Plus – A detailed guide on subtitle formats and standards

This past Friday, I wrapped up delivering 10 episodes of a travel show for American Public Television (APT), so I wanted to share my delivery workflow for captioning a broadcast show. This topic is a little tricky since my favorite finishing tool, DaVinci Resolve, doesn’t support delivering both 608 & 708 broadcast captioning/subtitling standards.

While Resolve supports CEA-608 captions in .mov and .mxf containers, that standard is for legacy analog transmission. A newer CEA-708 standard was created for digital broadcast. An undocumented feature in Resolve is that MXF containers (only) can be embedded with either 608 or 708 captions—but not both!

Broadcasters asking for -608 captions will likely ask for -708 deliverables, as APT asked us to do. Plus, APT wanted .scc format files for the deliverables, which Resolve doesn’t support either importing or exporting. Therefore, DaVinci Resolve was incapable of delivering my final air master.

How did I handle these deliverables without (sadly) using DaVinci Resolve?

That’s what this Insight is about.

Understanding broadcast closed captions

I haven’t dealt with broadcast captioning for over 15’ish years. I usually color grade, and someone else does delivery.

But this season, I was asked to handle the final delivery for the show. This meant, among other things, I also needed to handle the initial transcription, embedding, and verifying of the transcription within the final render, plus adhere to the deliverable spec. Here’s that portion of the APT delivery document:

BOTH 608 & 708 captions [are] required and must be embedded in the program:

• All media must contain embedded captions on SDID 01 for CEA708
• SCC formatted Captioning file (.scc extension)

For creating the subtitles, I briefly considered using DaVinci Resolve’s machine-learning transcription tool, which works well enough for Mixing Light Insights.

However, Resolve’s ‘AI’ doesn’t follow broadcast captioning style guides and is very inconsistent with breaking up lines when there are multiple speakers. Plus, without an integrated Find & Replace function for spelling (a glaring omission), I decided that approach was a no-go.

For broadcast deliverables with tight, last-minute turnarounds, DaVinci Resolve’s auto-subtitling solution doesn’t cut it.

Instead, I used a 3rd party captioning service, and they delivered the .SCC file to me.

So, the next problem to solve is:
How do I embed the .SCC caption file into the final MXF OP1a deliverable?

As of November 2024, here’s what DaVinci Resolve supports (via the User Manual):

Currently, DaVinci Resolve [imports] subtitle files in multiple formats such as .srt, .vtt, .xml, and .ttml.

Unfortunately, Resolve does not import .SCC files. But what about export?

I quickly concluded that my final delivery could NOT be 100% self-contained in DaVinci Resolve 19.1. So what did I do?

How did I deliver a final MXF with embedded 608 and 708 captions?

This video Insight is about my workflow for delivering an MXF file with embedded CEA-608 and CEA-708 captions.

The key aspect of my workflow is to render the final MXF out of Resolve without ever re-rendering the final MXF deliverable.

TL;DR

If you want to get straight to the point, I used CineXtools to embed the captions and Premiere Pro to verify the final deliverable before uploading to APT.

• CineXtools – I chose CineX because it merely re-wraps the MXF container when adding captions. It does not re-encode, ensuring the video’s image quality does not degrade. It also has a half-dozen additional uses, which I didn’t require. The downside is that it is pricey. But, I did price the annual subscription into the quote for this series.
  
  Also, CineXtools has full caption editing controls. Several times, just hours before delivery, I needed to make last-minute changes to the captions – at one point, requiring removing and replacing several lines, including new timings. It was brilliantly easy and efficient.
  
• Premiere Pro – I used Premiere as a verification tool. I was surprised to learn it has extremely robust caption support, including importing embedded 608 and 708 captions. It also exports to the SCC format. But I didn’t want to re-render the files, since I don’t yet fully trust Premiere’s render engine (PrPro is undergoing extensive re-coding of its rendering pipeline, and I’m not ready to trust it for short-turnaround broadcast deliveries).
  
  But, I was pleasantly surprised to learn that Premiere does have a Search & Replace function for fixing mis-spellings throughout an entire subtitle track! I’ve been waiting for this feature in Resolve for several years.

About this video Insight

In this video, you’ll see my workflow from Resolve through CineXtools and into Premiere, which will allow you to evaluate these tools before embarking on this workflow.

You’ll also see why I think Premiere’s subtitle toolkit is FAR superior to DaVinci Resolve’s.

In my opinion, Resolve has a decent subtitle workflow, but it is unfinished and severely lacking for professional broadcast deliverables (especially when compared to Premiere Pro).

Learn more about CEA-608 and -708 captions for delivery formats

While researching this topic, I asked a few LLMs to summarize the topic. Grok 3 did an amazing job; I’ve copied its response below. But, I did break it into four parts for easier reading. I also included its references to original sources. You can find the original Grok discussion here.

Resources mentioned in this Insight

Related Insights

– Patrick