I need to observe this more closely.
For a quick test I just started an FTA HD channel, pressed pause and then started fast forwarding. Strangely, there was no flickering at all.
An hour ago I started watching a recording of a Pay TV channel which was still ongoing. When fast forwarding - at least at 2x and 4x speeds - I am pretty sure the display was flickering at either speed.
After the recording had finished I started watching the same recording from the beginning and when fast forwarding, to my surprise, there was no flickering.
I will test FTA, FTA HD, Pay TV and Pay TV HD at various FF speeds to see if it makes any difference.
Update: I am not quite seeing the systematics behind it. On FTA HD channels it seems to occur less frequently. On the Pay TV channel I have it - no matter if SD or HD. And at lower FF speeds (2x, 4x) it happens more frequently than at higher FF speeds. This is from a few tests I did. But maybe the effect is at pure random.
Interestingly while testing, the below lines are filling up kodi.log:
xml:
23:41:00.011 T:139857870415616 WARNING: CRenderManager::WaitForBuffer - timeout waiting for buffer
23:41:26.931 T:139861320571264 WARNING: Previous line repeats 49 times.
23:41:26.931 T:139861320571264 ERROR: CVaapiTexture::Map - Error: invalid VASurfaceID(6)
23:41:30.519 T:139857870415616 ERROR: Previous line repeats 26 times.
23:41:30.519 T:139857870415616 WARNING: CRenderManager::WaitForBuffer - timeout waiting for buffer
23:41:30.552 T:139861320571264 ERROR: CVaapiTexture::Map - Error: invalid VASurfaceID(6)
23:41:30.574 T:139857870415616 WARNING: VAAPI::FFGetBuffer - no surface available - dec: 0, render: 3
23:41:30.610 T:139857870415616 WARNING: CRenderManager::WaitForBuffer - timeout waiting for buffer
23:41:30.998 T:139857878972160 ERROR: VAAPI::CheckSuccess - Error: surface is in use(16)
23:41:31.151 T:139861320571264 ERROR: CVaapiTexture::Map - Error: invalid VASurfaceID(6)
23:41:31.153 T:139857870415616 WARNING: CRenderManager::WaitForBuffer - timeout waiting for buffer
23:41:31.195 T:139857878972160 ERROR: VAAPI::CheckSuccess - Error: surface is in use(16)
23:41:31.312 T:139861320571264 ERROR: Previous line repeats 1 times.
23:41:31.312 T:139861320571264 ERROR: CVaapiTexture::Map - Error: invalid VASurfaceID(6)
23:41:31.893 T:139857870415616 ERROR: Previous line repeats 3 times.
23:41:31.893 T:139857870415616 WARNING: CRenderManager::WaitForBuffer - timeout waiting for buffer
23:41:31.893 T:139861320571264 ERROR: CVaapiTexture::Map - Error: invalid VASurfaceID(6)
23:41:32.375 T:139857878972160 ERROR: Previous line repeats 2 times.