They are exr's. So I have the following
aovs: beauty, diffuse_albedo_noice, variance,
N_noice, Z_noice:
./oiiotool beauty.0001.exr
diffuse_albedo_noice.0001.exr --chappend -chname
,,,,"diffuse_albedo_noice.R","diffuse_albedo_noice.G","diffuse_albedo_noice.B"
-o merged_bd.0001.exr
./oiiotool merged_bd.0001.exr
variance.0001.exr --chappend --chname
,,,,,,,"variance.R","variance.G","variance.B","variance.A"
-o merged_bdv.0001.exr
...<all the aovs>...
./oiiotool ...-o merged_all_aovs.0001.exr
When I query the final merged image,
./oiiotool --info:verbose=1
merged_all_aovs.0001.exr
maya_render.0001.exr: 960 x 540, 15
channel, half openexr channel list: R, G, B, A,
Z_noice, N_noice.Y, N_noice.Z, N_noice.X,
diffuse_albedo_noice.R, diffuse_albedo_noice.G,
diffuse_albedo_noice.B, variance.R, variance.G,
variance.B, variance.A
arnold / AA_samples: 2
arnold / aovs / RGBA / filter: "gaussian_filter"
arnold / aovs / RGBA / filter_width: 2
arnold / aovs / RGBA / lpe: 1
arnold / aovs / RGBA / source: "RGBA"
arnold / auto_transparency_depth: 10
arnold / bounds_max_x: 959
arnold / bounds_max_y: 539
...
It is missing the aovs after beauty.
Comparing it to the render from Maya
maya_render.0001.exr: 960 x 540, 15
channel, half openexr channel list: R, G, B, A,
Z_noice, N_noice.Y, N_noice.Z, N_noice.X,
diffuse_albedo_noice.R, diffuse_albedo_noice.G,
diffuse_albedo_noice.B, variance.R, variance.G,
variance.B, variance.A
arnold / AA_samples: 2
arnold / aovs / diffuse_albedo_noice / filter:
"gaussian_filter"
arnold / aovs / diffuse_albedo_noice / filter_width: 2
arnold / aovs / diffuse_albedo_noice / lpe: 1
arnold / aovs / diffuse_albedo_noice / source:
"diffuse_albedo"
arnold / aovs / N_noice / filter: "gaussian_filter"
arnold / aovs / N_noice / filter_width: 2
arnold / aovs / N_noice / source: "N"
arnold / aovs / RGBA / filter: "gaussian_filter"
arnold / aovs / RGBA / filter_width: 2
arnold / aovs / RGBA / lpe: 1
arnold / aovs / RGBA / source: "RGBA"
arnold / aovs / variance / filter: "variance_filter"
arnold / aovs / variance / filter_width: 2
arnold / aovs / variance / lpe: 1
arnold / aovs / variance / source: "RGBA"
arnold / aovs / Z_noice / filter: "gaussian_filter"
arnold / aovs / Z_noice / filter_width: 2
arnold / aovs / Z_noice / source: "Z"
arnold / auto_transparency_depth: 10
arnold / bounds_max_x: 959
arnold / bounds_max_y: 539
...