MediaConvert not preserving color metadata when transcoding AV1 → H.264

This issue is related to how MediaConvert handles color metadata during transcoding. When you're seeing "unknown-unknown-unknown" in your output instead of the expected "1-1-1" color profile, it's likely because MediaConvert couldn't properly interpret or follow the color metadata from your input.

By default, MediaConvert sets your color space to "Follow," which should maintain the same color space from input to output. However, if your input has missing or incomplete color metadata (which includes color primaries, transfer function, and matrix coefficients), MediaConvert may not be able to properly preserve this information.

To fix this issue, you should:

1. In your input settings, under "Video selector," manually specify the correct "Color space" for your input video
2. Set "Color space usage" to "Force" (this tells MediaConvert to use your specified color space regardless of what's in the input metadata)
3. Keep your output setting "Color metadata" set to "Insert"

This approach will ensure that MediaConvert has the correct color information to work with and will properly insert it into your H.264 output. Without explicitly specifying the color space and forcing its usage, MediaConvert might not be able to correctly interpret the color metadata from your AV1 source, resulting in the "unknown" values you're seeing.
Sources
Warning codes - MediaConvert
Replacing inaccurate or missing HDR metadata - MediaConvert
Passing through HDR content - MediaConvert

Hello,

To answer your question, we require details that are non-public information. Please open a support case with AWS using the following link: https://console.aws.amazon.com/support/home#/case/create

To troubleshoot the issue, we would kindly request you to share the following information while opening the support case:

1. Media Convert JOB ID.
2. Region which you are using.
3. All the source files.
4. Output file (if possible).

Thankyou