MediaConvert cannot set output group 708 service number

When working with embedded captions in AWS MediaConvert, there are some limitations when trying to remap caption channel numbers between 608 and 708 formats.

For SCC input captions that are being converted to embedded captions in the output, MediaConvert provides options to specify both the destination 608 channel number and the 708 service number. However, for embedded input captions (as in your case), the service has more restrictions.

When using embedded captions as input and setting "Force 608 to 708 upconvert=Upconvert", MediaConvert will maintain the same channel mapping - meaning CC1 will map to service 1, CC3 will map to service 3, etc. The API doesn't currently support remapping embedded caption channels to different service numbers in the way you're trying to achieve.

For MXF XDCAM HD outputs specifically, MediaConvert will copy your embedded captions to both the smpte 436 ancillary track and include them in the video stream. However, the limitation on remapping service numbers still applies.

You might need to consider alternative workflows to achieve your specific caption channel mapping requirements, such as:

1. Extract the captions from your source to an intermediate format (like SCC)
2. Create a new MediaConvert job using those SCC files as input captions
3. Then specify the exact destination 608 channel numbers and 708 service numbers you need

This multi-step approach would give you more control over the caption channel mapping than is currently possible with direct embedded-to-embedded caption conversion.
Sources
CEA/EIA-608 and CEA/EIA-708 (embedded) output captions - MediaConvert
Presets - AWS Elemental MediaConvert API Reference
Jobs id - AWS Elemental MediaConvert API Reference