Transmission of volumetric images in multiplane imaging format
Methods and apparatus for transmission of volumetric images in the MPI format. According to an example embodiment, texture and alpha layers of multiplane images are packed, as tiles, into a sequence of video frames. The sequence of video frames is then compressed to generate a video bitstream, which is transmitted together with a metadata bitstream specifying at least the parameters of the packing arrangement for the tiles in the sequence of video frames. Example packing arrangements include various selectable spatial and temporal arrangements for texture layers, alpha layers, and camera views. In some examples, the metadata bitstream is implemented using a SEI message and includes parameters selected from the group consisting of a size of the reference view, the number of layers in the multiplane image, the number of simultaneous views, one or more characteristics of the packing arrangement, layer merging information, dynamic range adjustment information, and reference view information.
1 . A method for decoding a bitstream, the method comprising:
receiving a coded bitstream comprising a sequence of multiplane images and metadata comprising profile parameters to decode the coded bitstream according to an MPEG Immersive video (MIV) packed profile; and
decoding the coded bitstream according to the metadata, wherein the metadata indicate:
using a single decoder;
presence of packed video containing texture and transparency without occupancy and geometry;
a single MPI view; and
a single atlas with a single tile.
2 . The method of claim 1 , wherein the metadata further indicate that there is only one patch per MPI layer, and a layer patch has width and height equal to a width and a height of a camera projection plane.
3 . The method of claim 1 , wherein indicating using a single decoder comprises setting ptl_max_decodes_idc=0.
4 . The method of claim 1 , wherein indicating the presence of packed video containing texture and transparency, without occupancy and geometry, comprises setting:
vps_packed_video_present_flag[atlasID]=1;
pin_attribute_present_flag[atlasID]=1;
pin_attribute_count[atlasID]=2;
pin_attribute_type_id[atlasID][0]=ATTR_TEXTURE;
pin_attribute_type_id[atlasID][1]=ATTR_TRANSPARENCY;
vps_occupancy_video_present_flag[atlasID]=0;
pin_occupancy_present_flag[atlasID]=0;
vme_embedded_occupancy_enabled_flag=0;
vps_geometry_video_present_flag[atlasID]=0; and
pin_geometry_present_flag[atlasID]=0.
5 . The method of claim 1 , further indicating disabling scaling of geometry and occupancy by setting:
vme_geometry_scale_enabled_flag=0;
vme_occupancy_scale_enabled_flag=0; and
asme_occupancy_scale_enabled_flag=0.
6 . The method of claim 1 , wherein indicating a single MPI view comprises setting mvp_num_views_minus1=0.
7 . The method of claim 1 , wherein indicating a single atlas with a single tile comprises setting:
vps_atlas_count_minus1[atlasID]=0 for indicating a single atlas;
gm_group_count=1 for indicating a single group; and
afti_single_tile_in_atlas_frame_flag=1 for indicating a single atlas with a single tile.
8 . The method of claim 3 , wherein patch width and height information is signaled as:
AtlasPatch2dSizeX[p]=ci_projection_plane_width_minus1[v]+1; and
AtlasPatch2DsizeY[p]=ci_projection_plane_height_minus1[v]+1,
wherein p denotes a patch index and v denotes a view identifier.
9 . The method of claim 3 , wherein indicating all patches are generated for a single MPI camera view comprises setting:
pdu_projection_id[tileID][p]=mvp_view_id[v],
wherein p denotes a patch index and v denotes a view identifier.
10 . The method of claim 3 , wherein indicating that a single patch is used per layer comprises setting
Pdu3dOffsetD[tileID][p]!=Pdu3dOffsetD[tileID][q] for all p!=q,
wherein p denotes a patch index and v denotes a view identifier.
11 . The method of claim 1 , wherein the metadata further indicate that only intra atlas tile and intra patch are being used.
12 . A non-transitory computer-readable-medium storing instructions that, when executed by a processor of a computer system, cause the computer system to perform operations comprising the method according claim 1 .
13 . An apparatus comprising a processor and configured to perform the method recited in claim 1 .