Thanks guys
I tried your suggestions, but still the only way to get something useful is via the "deinterlace=" switch in DGSource. All other methods produce blended crap. Even when I separate the fields, all fields are blended. Maybe something is broken in avisynth here. I'll reinstall it from scratch.
Thanks for the hint about field shifted pseudo-interlace. Actually that file was produced by VEGAS. The original source was a progressive .mp4 VFR "by name" clip, 1920x1080p29.97 (nominal). For blu-ray compliance VEGAS has to convert this to interlaced. Apparently VEGAS did this by producing a field-shifted pseudo-interlace clip. I was wondering why it did it this way, but perhaps something is broken here. On the other hand I am aware that these "VFR by name" footage can produce problems with NLEs.
Is there a way to convert VFR to CFR without re-enoding the video?
Edit:
Frame view:
a) Decoding with DirectShowSource() returns clear frames at rate 59.94 as aabbccddee…… (repeated clear frames at double rate)
b) Decoding with DGSource() returns blended frames at rate 29.97 fps (all blended at single rate)
c) Decoding with DGSource(......, deinterlace=1) returns clear frames at 29.97fps as abcdefg.... (clear frames at single rate)
Field view:
a1) Decoding with DirectShowSource() followed by separatefields() returns clear fields at rate 119.88 fields per second as aaaabbbbccccddddeeee..... (clear repeated fields at 4-fold rate = double field rate)
b1) Decoding with DGSource() followed by separatefields() returns blended fields at rate 59.94 as abcdefg....... (all fields blended at field rate)
c1) Decoding with DGSource(....., deinterlace=1) followed by separatefields() returns clear fields at rate 59.94 as aabbccddee ...… (repeated fields at field rate)
Obviously the 2 Source filters do not produce the same results. With DGSource I can obtain unblended output with the internal "deinterlace=" switch only, it seems.
The field shift correction with separatefields().trim(1,0).weave() works with the DSS filter but fails with DGSource.
![Confused :?](./images/smilies/icon_e_confused.gif)