troubleshooting.md 1.1 KB
Troubleshooting Guide
Table of Contents
608/708 Caption Parsing
I have a stream with caption data in more than one field, but only captions from one field are being returned
You may want to confirm the SEI NAL units are constructed according to the CEA-608 or CEA-708 specification. Specifically:
- that control codes/commands are doubled
- control codes starting from 0x14, 0x20 and ending with 0x14, 0x2f in field 1 are replaced with 0x15, 0x20 to 0x15, 0x2f when used in field 2
- control codes starting from 0x1c, 0x20 and ending with 0x1c, 0x2f in field 1 are replaced with 0x1d, 0x20 to 0x1d, 0x2f when used in field 2
I am getting the wrong times for only some captions, other captions are correct
If your content includes B-frames, there is an existing issue to fix this problem. We recommend that you ensure that all the segments in your source start with keyframes, to allow proper caption timing.