Timestamp Camera is the best app (maybe only) for adding timestamps to new videos.
Characteristics:
* Support to turn off the shutter sound when shooting
* All time effects are in real time and can be used when taking photos or videos
* Can change effect, switch camera when recording
* Support portrait and landscape
* Support for resolution of changes
Supported Android
{Varies with device}
Supported Android Version:-
Jelly Bean(4.1–4.3.1)- KitKat (4.4–4.4.4)- Lollipop (5.0–5.0.2) – Marshmallow (6.0 – 6.0.1) – Nougat (7.0 – 7.1.1) – Oreo (8.0-8.1) – Pie (9.0)