Color space / BT.709
Watch as an animation →Put a tag on the file saying "this video was made in BT.709 color," so the color and brightness don't look different from player to player.
Final export, when moving to another program, and when colors look different on a phone and a PC.
The Seedance 2.5 1080p confirmed version comes out as 10-bit HEVC with the BT.709 tag (color_space, transfer, and primaries all bt709, tv range), and the tags carried over to the final re-encoded with libx264 (ffprobe, 2026-10-13). I did not set the tags directly in the encode command, so if sources with empty tags get mixed in, add -colorspace bt709 -color_primaries bt709 -color_trc bt709 -color_range tv to the output. When you convert Pillow PNG (RGB) captions and logos to yuv without specifying the matrix, they may be converted with BT.601, and brand colors can shift slightly. If exact color matters, match it with scale=out_color_matrix=bt709. To check, use ffprobe -v error -select_streams v:0 -show_entries stream=color_space,color_transfer,color_primaries -of default=nw=1 input.mp4. YouTube also recommends BT.709 for SDR uploads.
Tag and convert the export as BT.709 so every player shows the same colors: ffmpeg -i in.mp4 -vf scale=out_color_matrix=bt709:out_range=tv -colorspace bt709 -color_primaries bt709 -color_trc bt709 -color_range tv -c:v libx264 -crf 17 -pix_fmt yuv420p -c:a copy out.mp4. Check it with ffprobe.
Not verified