[FFmpeg-user] OpenEXR input with cropped data window produces black output

[Moritz Barsnick]

On Tue, Jan 03, 2017 at 11:56:06 +0000, Kevin Wheatley wrote:
> dataWindow (type box2i): (873 318) - (1174 625)
> displayWindow (type box2i): (0 0) - (1919 1079)

"file" (the "magic" program) kindly reports these as well.

> ffmpeg -y -loglevel debug -apply_trc linear -i /tmp/exr_test.%04d.exr
> -c:v libx264 /tmp/test.mov
> 
> I end up with a full frame of black, changing EXR compression type
> (none, zip 1, PIZ, etc) or data type (16 bit/32 bit) does not make a
> difference, nor does switching to mp4 output container, or using mjpeg
> as an codec.

ffmpeg's exr implementation does seem to have some shortcomings. What
is to happen with these windows is described here:
https://github.com/openexr/openexr-images/tree/master/DisplayWindow

Sample t04.exr has
dataWindow: (0 0)-(399 299)
displayWindow: (0 0)-(369 279)

but ffmpeg chokes on it:
[exr @ 0xb8b8dc0] Wrong or missing size information.

I expanded ffmpeg's messages a bit:
[EXR @ 0xba3f260] Found dataWindow: xmin = 0, ymin = 0, xmax = 399, ymax = 299
[EXR @ 0xba3f260] Found displayWindow: w = 370, h = 280
[exr @ 0xba2fdc0] Wrong or missing size information: w = 370, h = 280, xmin = 0, xmax = 399, ymin = 0, ymax = 299, xdelta = 400

Without digging deeper into ffmpeg's EXR code, I'm not sure it handles
those windows properly, according to the quoted link.

Moritz