Video Assembly Label
video-assembly-label
Burns an auto-timed caption over a specific segment in the assembled timeline — Imgix calculates the timing so the label appears exactly while that segment is on screen.
video-assembly-label[N] accepts a UTF-8 string up to 200 characters. A Base64 twin video-assembly-label64[N] is also available for strings with reserved characters.
The label fades in after the transition into the segment and fades out before the transition out. Imgix performs the timeline math automatically — you do not need to compute video-txt-start/-end pairs.
Label style parameters
All labels share a single set of style parameters. Style them once with video-assembly-label-* — per-label styling is deliberately not available.
| Parameter | Default | Description |
|---|---|---|
video-assembly-label-font | System default | Font family |
video-assembly-label-size | 32 | Font size in pixels |
video-assembly-label-weight | 700 | Font weight |
video-assembly-label-color | FFFFFF | Text color (hex) |
video-assembly-label-bg | 00000099 | Pill background color (none = no pill) |
video-assembly-label-pad | 12 | Padding between text and pill edge |
video-assembly-label-radius | 8 | Pill border radius in pixels |
video-assembly-label-align | bottom,left | Text alignment within the frame |
video-assembly-label-x | — | Exact horizontal pixel position |
video-assembly-label-y | — | Exact vertical pixel position |
video-assembly-label-transition | fade | Entrance and exit animation |
video-assembly-label-transition-dur | 0.3 | Transition duration in seconds |
The style grammar follows the txt-* parameter family. Labels use the same 20-layer text overlay budget — labels past the limit are dropped with a warning, and the per-segment timing is still tracked correctly for those that remain.
Labels are reported in X-Imgix-Video-Operations under the txt token.