https://bugs.freedesktop.org/show_bug.cgi?id=92220
--- Comment #14 from Christian König deathsimple@vodafone.de --- (In reply to Peter Frühberger from comment #13)
So @Christian happy for pointers on how to get it going.
Yeah, completely agree with you. Software workarounds are very common in OpenGL and nothing unusual.
Here are a few pointers into the code: 1. vlVdpVideoSurfaceGallium() in src/gallium/state_trackers/vdpau/surface.c. That one is called to "export" video surfaces to OpenGL and the right place to convert from frame to field.
2. vlVdpDecoderRender() in src/gallium/state_trackers/vdpau/decode.c. Here we reallocate the buffer backing the surface before the decoding if the frame/field flag doesn't match what the decoder expects.
3. vlVdpVideoMixerRender() in src/gallium/state_trackers/vdpau/mixer.c. Here we use a vl_compositor_render() to compose the mixed output picture.
Essentially you only need to test if the surface is field based and if not reallocate it and either use vl_compositor_render() or pipe->blit() to copy the frame into fields.