Same exactly thing happens to me on very similar hardware, but I think I know what it is.
I have an Intel NUC. This started happening when I upgraded to 17.6. If I disable the VA-API hardware acceleration, the forward/rewind works fine.
Remember these NUCs have a Haswell Intel CPU with integrated graphics that loads the i965 driver for Intel G45 & HD Graphics Family.
Now and I'm sorry, I don't think it's the driver or the kernel fault. With VLC with VA-API enable, you can skip all around fine. With Kodi, you can actually see errors on StepBack like these:
Code:
22:52:26.707 T:140082223740352 DEBUG: OnKey: 169 (0xa9, obc86) pressed, action is StepBack
(...)
22:52:27.587 T:140080471807744 DEBUG: VAAPI - open decoder
22:52:27.588 T:140078638671616 DEBUG: Thread Vaapi-Output start, auto delete: false
22:52:27.588 T:140078638671616 NOTICE: COutput::OnStartup: Output Thread created
22:52:27.592 T:140078638671616 DEBUG: VAAPI::COutput::CreateEGLContext - created context
22:52:27.594 T:140078564366080 DEBUG: CVideoPlayer::HandleMessages - player started 1
22:52:27.596 T:140078638671616 DEBUG: VAAPI::COutput::InitBufferPool - Surfaces created
22:52:27.596 T:140080471807744 DEBUG: CDVDVideoCodecFFmpeg - Updated codec: ff-h264-vaapi
22:52:27.596 T:140080471807744 DEBUG: ffmpeg[7F6706C31700]: [h264] Using deprecated struct vaapi_context in decode.
22:52:27.597 T:140080471807744 DEBUG: CVideoPlayerVideo::CalcDropRequirement - hurry: 0
22:52:27.597 T:140080471807744 ERROR: ffmpeg[7F6706C31700]: [h264] Got unexpected packet size after a partial decode
22:52:27.597 T:140080471807744 ERROR: Decode - avcodec_decode_video returned failure
22:52:27.597 T:140080471807744 DEBUG: CVideoPlayerVideo - video decoder returned error
22:52:27.597 T:140080471807744 DEBUG: CVideoPlayerVideo::CalcDropRequirement - hurry: 0
22:52:27.598 T:140080471807744 DEBUG: Previous line repeats 1 times.
22:52:27.598 T:140080471807744 WARNING: CVideoSurfaces::ClearReference - surface invalid
22:52:27.598 T:140080471807744 DEBUG: CVideoPlayerVideo::CalcDropRequirement - hurry: 0
22:52:27.608 T:140082223740352 DEBUG: Previous line repeats 1 times.
22:52:27.608 T:140082223740352 NOTICE: VAAPI::Close
I can disable the hardware acceleration and these little computers handle the data just fine but after a while the fan cooler starts accelerating and making an annoying noise so I would prefer to use the VA-API hardware acceleration.
The thing is, I also have Debian, and I also use deb-multimedia.org which is NOT the official Debian repo and are supposed to be vanilla kodi. If you guys insist is a Debian problem, and not a Haswell problem in Kodi (or the ffmpeg that Kodi uses), the only solution to discard that theory is to compile the whole thing manually. But I think it's a Haswell problem on Kodi because it wasn't happening in 16.x using the same non-official repo.