ffmpeg crash when using d3d11va hardware acceleration while transcoding

[Evgeny]

Summary of the bug:
FFmpeg will crash if using dx11 or dx9 hw surface & amf or nvenc encoders while transcoding.

How to reproduce:

% ffmpeg.exe -y -hwaccel d3d11va -hwaccel_output_format d3d11 -i input_h264_480x360.mp4 -c:v h264_amf out.mp4
% ffmpeg.exe -y -hwaccel dxva2 -hwaccel_output_format dxva2_vld -i input_h264_480x360.mp4 -c:v h264_amf out.mp4

If I add -extra_hw_frames 14, then it works:

% ffmpeg.exe -y -hwaccel d3d11va -hwaccel_output_format d3d11 -extra_hw_frames 14 -i input_h264_480x360.mp4 -c:v h264_amf out.mp4
% ffmpeg.exe -y -hwaccel dxva2 -hwaccel_output_format dxva2_vld -extra_hw_frames 14 -i input_h264_480x360.mp4 -c:v h264_amf out.mp4


ffmpeg version
built on master