c_major wrote:
If some rare cases the preview might not be very accurate due to the optimization. Have you compared the source with the actual export result?
Yes good sir, I certainly have. 
NotADevWinkWink wrote:
Hi bLOCKbOYgAMES,
In the first screenshot, I notice you're in the sequence preview. The clip and sequence previews cache things with a lossy compression, so that's probably what's causing the artifacts. That, however, doesn't affect the exported files (VideoPad doesn't use the cache system for exports).
A quick way you can check if the artifacts are a problem before export is to open up the preview dialog (Ctrl+U), as that dialog doesn't use the cache either (if you have many effects, playback probably won't work smoothly on this dialog), then seek to the 1:13.373 position in your top screenshot.
Do you mind telling us what export formats/encoding settings you've tried so far?
P.S. Aw yeah Dishonored 2
I posted the screenshot from the preview to give an indication of the final export video artefacts. I understand that the preview may well be of a lower quality and I don't care that much about what the preview looks like, but the final export looks the same.
To answer your question, for the export formats/encoding I have tried so far:
Preset: always custom (The reason is I want 60fps on the final video, and using HD 1080p only gives the 29 NTSC output.)
File Format: I have tried .mp4, .flv and .avi
Resolution: seeing as I am exporting to youtube at 1080p. I have been using the 1920x1080p - youtube1080p resolution.
frame rate: 60fps, with the constant framerate box checked. 
For encoder options, I have tried both H264 and MPEG4
In both cases I have set the slider to the highest quality settings.
for MPEG4 I have left the averate bitrate at 8192 and highest bitrate at 16384 (which seems default.) for audio I have left the setting at 320 kbits/sec.
for H264 I have left the audio bitrate at 320 kbits/sec.
And props for recognising dishonored 2. Yeah I am enjoying it very much. I preordered it so I could get my vids up on youtube as soon as it was officially released. Unfortunately, I got stuck with technical issues. grrr.
That said, thank you both for the replies, much appreciated, and hopefully get this resolved soon.
The strangest thing is that all the different outputs are tiny for this particular vid, 1 - 4 Gb. Yet all my other videos were in the order of 15 - 25 Gb. This seems like the biggest problem to me. I don't know what is going on with that?
cheers again.