Luma assets are masks that are applied to everything in the same track independently. If you happen to have a clip in your track with a luma asset in that same track the mask will show on each of the clips in the track.
The way to solve for this is to only have clips in your track that you want affected by the luma asset. In the case of your watermark the solution is to take the clip out of the track and place it on a separate track above the video that you want to place the watermark on.
I’ve sent you a DM with a non-blinking version of your edit, but see below a general example:
{
"timeline": {
"soundtrack": {
"src": "https://shotstack-assets.s3-ap-southeast-2.amazonaws.com/music/unminus/palmtrees.mp3",
"effect": "fadeOut"
},
"fonts": [
{
"src": "https://shotstack-assets.s3.amazonaws.com/fonts/Lato-Bold.ttf"
}
],
"background": "#000000",
"tracks": [
{
"clips": [
{
"asset": {
"type": "luma",
"src": "https://shotstack-assets.s3.amazonaws.com/luma-mattes/melts/melting-center.mp4"
},
"start": 3.6,
"length": 2
},
{
"asset": {
"type": "video",
"src": "https://shotstack-assets.s3-ap-southeast-2.amazonaws.com/footage/table-mountain.mp4"
},
"start": 0,
"length": 5
},
{
"asset": {
"type": "html",
"html": "<p>This html asset is affected by the luma matte because it sits in the same track",
"css": "p { font-size: 48px; color: #ffddd2; font-family: \"Lato Bold\"; margin: 15px; }",
"background": "#83c5be",
"width": 800,
"height": 250
},
"start": 1,
"length": 4.6
}
]
},
{
"clips": [
{
"asset": {
"type": "html",
"html": "<p>This html asset is NOT affected by the luma matte because it sits in a separate track",
"css": "p { font-size: 48px; color: #ffddd2; font-family: \"Lato Bold\"; margin: 15px; }",
"background": "#83c5be",
"width": 800,
"height": 250
},
"start": 5.6,
"length": 5
}
]
},
{
"clips": [
{
"asset": {
"type": "luma",
"src": "https://shotstack-assets.s3.amazonaws.com/luma-mattes/melts/melting-center-flipped.mp4"
},
"start": 7.2,
"length": 2
},
{
"asset": {
"type": "video",
"src": "https://shotstack-assets.s3-ap-southeast-2.amazonaws.com/footage/road.mp4"
},
"start": 3.6,
"length": 5
}
]
},
{
"clips": [
{
"asset": {
"type": "video",
"src": "https://shotstack-assets.s3-ap-southeast-2.amazonaws.com/footage/lake.mp4"
},
"start": 7.2,
"length": 5,
"transition": {
"out": "fade"
}
}
]
}
]
},
"output": {
"format": "mp4",
"resolution": "1080"
}
}