Common autostereoscopic 3D displays are based on multi-view projection. The diversity of resolutions and
number of views of such displays implies a necessary flexibility of 3D content formats in order to make broadcasting
efficient. Furthermore, distribution of content over a heterogeneous network should adapt to an available
network capacity. Present scalable video coding provides the ability to adapt to network conditions; it allows for
quality, temporal and spatial scaling of 2D video. Scalability for 3D data extends this list to the depth and the
view domains. We have introduced scalability with respect to depth information. Our proposed scheme is based
on the multi-view-plus-depth format where the center view data are preserved, and side views are extracted
in enhancement layers depending on depth values. We investigate the performance of various layer assignment
strategies: number of layers, and distribution of layers in depth, either based on equal number of pixels or histogram
characteristics. We further consider the consequences to variable distortion due to encoder parameters.
The results are evaluated considering their overall distortion verses bit rate, distortion per enhancement layer, as
well as visual quality appearance. Scalability with respect to depth (and views) allows for an increased number
of quality steps; the cost is a slight increase of required capacity for the whole sequence. The main advantage is,
however, an improved quality for objects close to the viewer, even if overall quality is worse.