Constant libaom_sys::AV1D_SET_OUTPUT_ALL_LAYERS

pub const AV1D_SET_OUTPUT_ALL_LAYERS: aom_dec_control_id = 280;

Codec control function to indicate whether to output one frame per temporal unit (the default), or one frame per spatial layer, int parameter

In a scalable stream, each temporal unit corresponds to a single “frame” of video, and within a temporal unit there may be multiple spatial layers with different versions of that frame. For video playback, only the highest-quality version (within the selected operating point) is needed, but for some use cases it is useful to have access to multiple versions of a frame when they are available.