corruption with VAAPI when playing VC-1 interlaced

[aufkrawall]

When playing a VC-1 interlaced file with

ffmpeg -hwaccel vaapi -i "1080i_vc-1_29.97fps.mkv" -f matroska - | ffplay -

I get corrupted and extremely stuttery video output:
​https://abload.de/img/screenshot20180323132pssrx.png

VDPAU works without issues with this format. However, VAAPI works fine with VC-1 non-interlaced and other formats.
Linux 4.15 and 4.16
mesa-git 18.1.0_devel.101112.ccc64f3133
ffmpeg 3.4.2 and 3.5.r90415.g4e1307c0f7

Can gladly provide logfiles if required.

Sample:
​https://drive.google.com/file/d/0BwxFVkl63-lERnhlY1pHeW5wbjQ/view?usp=sharing
(provided by Kodi Wiki)

[jkqxz]

I don't think VC-1 interlaced is supported by the Mesa VAAPI driver. Does it work with anything else?

[aufkrawall]

I can only test with Polaris GPU and unfortunately, neither Xorg info pages nor vainfo distinguish between VC-1 progressive and interlaced.
I'll report it for mesa if e.g. @jamrial thinks this isn't an ffmpeg issue.

[Hendrik]

VAAPI VC-1 interlaced support has landed only quite recently in avcodec, and during the development it was shown that Intel works now, but AMD does not. It is quite likely that this is a driver problem.

[Carl Eugen Hoyos]

As Intel works, I assume this cannot be fixed in FFmpeg.