Seedance 2.5 mov output for editing and extension, and Sume MP4

BytePlus says to use mov as both input and output for Seedance 2.5 video editing and extension, because it keeps color more precisely than mp4. Sume's Timeline 1.0 and Video filter docs describe MP4 results, so on Sume plan around MP4 and check the model catalog before assuming a mov option.

Vendor facts are from the BytePlus tutorial, read 2026-10-01. Sume facts are from Timeline 1.0 and Video filter.

What does BytePlus say about mov and mp4?

The output_format parameter defaults to mp4, described as the general-purpose format with the best compatibility. mov is the high color precision format for professional post-production such as color grading, keying and compositing. The page warns that mov uses H.264 video, yuv444p chroma sampling and PCM audio, and some players cannot play it.

What do Sume workflows return?

Timeline 1.0 assembles one audio spine plus ordered video slots into a long-form MP4, and its default output is 1080 by 1920. Video filter returns a new MP4. Neither page mentions a mov output.

If you are stitching clips, see Assemble long-form video.

Does this matter for extension chains?

On BytePlus, each extension round reads the previous video, so the recommendation is to keep the intermediate files in mov. On Sume, I found no mov-specific guidance. Keep each round as a separate job, keep the job ids, and decide on a delivery format only for the final render.

What should I do?

If your pipeline needs mov for a grade, run that step in your own tools after you download the MP4 from Sume. If MP4 is the delivery format anyway, the mov caveat does not apply to you.