Audio and Video
Apps can play short video and audio clips while the app is active and running in the foreground. You can use a movie element to embed clips in your interface and play video inline or you can play a clip in a separate interface. The system manages media file playback. For developer guidance, see WKInterfaceInlineMovie and WKInterfaceMovie.
Apps that play long, audio-only content — like music or audio books — can play or stream long audio clips through a connected Bluetooth headset when the app is inactive. In this scenario, the app initiates playback of a long audio clip and the system manages it in the background.
Keep audio and video clips short. Clips should be no longer than 30 seconds, and shorter is preferred. Long clips consume more disk space and require people to keep their wrists raised for longer periods of time, which can cause fatigue.
Use the recommended sizes and encoding values for media assets. In particular, avoid scaling video clips, which affects performance and results in a suboptimal appearance. The following table lists the recommended encoding and resolution values for audio and video assets. The audio encoding values apply to both movies and audio-only assets.
|Video codec||H.264 High Profile|
|Video bit rate||160 kbps at up to 30 fps|
|Resolution (full screen)||208px × 260px (portrait orientation)|
|Resolution (16:9)||320px × 180px (landscape orientation)|
|Audio||64 kbps HE-AAC|
Consider offering a Now Playing view. When you present a Now Playing view, people can control current or recently played audio without leaving your app. The system-provided Now Playing view also displays information about the current audio source — which might be another app on a person's Apple Watch or iPhone — and automatically selects the current or most recently used source. For developer guidance, see Adding a Now Playing View.
If necessary, consider creating custom audio player controls. For example, you might want to define custom increments for skipping forward or backward, or present content that's related to the playing audio, such as a sports score.
Use the previous end time when resuming playback of a long audio or video clip. Resuming playback at the previous stopping point lets people quickly continue where they left off.
Creating Movie Poster Images
When people tap a movie element's poster image, the element initiates playback of the video or audio in a modal view.
Create a poster image that’s representative of a video clip’s contents. Poster images let people make informed decisions about whether to view the clip associated with a movie. Avoid using an image that has nothing to do with the clip.
Avoid creating a poster image that looks like a system control. You want people to understand that they can tap a movie element for playback; you don’t want to confuse people by making movie elements look like something else.