Strange interlacing pattern

[-sTi-]

Hi

I am trying to convert a 1080p interlaced source taken from Bluray but am confused by the weird interlacing and ghosting pattern I see. It is a ballet recording "The Taming of the Shrew" from UNITEL media from 2022. Here is the media info of the whole file:
General
Format : Matroska
Format version : Version 2
File size : 25.6 GiB
Duration : 2 h 2 min
Overall bit rate mode : Variable
Overall bit rate : 29.9 Mb/s
Frame rate : 29.970 FPS
Movie name : THR TAMING OF THE SHREW
Encoded date : 2025-03-12 13:29:32 UTC
Writing application : MakeMKV v1.17.9 win(x64-release)
Writing library : libmakemkv v1.17.9 (1.3.10/1.5.2) win(x64-release)

Video
ID : 1
ID in the original source medium : 4113 (0x1011)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings : CABAC / 3 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 3 frames
Format settings, GOP : M=3, N=24
Format settings, Slice count : 4 slices per frame
Codec ID : V_MPEG4/ISO/AVC
Duration : 2 h 2 min
Bit rate mode : Variable
Bit rate : 22.0 Mb/s
Maximum bit rate : 34.0 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : MBAFF
Scan type, store method : Interleaved fields
Scan order : Top Field First
Bits/(Pixel*Frame) : 0.354
Stream size : 18.8 GiB (73%)
Writing library : x264 core 159 r2991 1771b55
Encoding settings : cabac=1 / ref=4 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=8 / psy=1 / psy_rd=1.00:0.00 /
mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 /
threads=24 / lookahead_threads=4 / sliced_threads=0 / slices=4 / nr=0 / decimate=1 / interlaced=tff / bluray_compat=1 / constrained_intra=0 /
bframes=2 / b_pyramid=1 / b_adapt=1 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=0 / keyint=24 / keyint_min=1 /
scenecut=40 / intra_refresh=0 / rc_lookahead=26 / rc=2pass / mbtree=1 / bitrate=22000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 /
qpmax=69 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / vbv_maxrate=34000 / vbv_bufsize=30000 / nal_hrd=vbr / filler=0 / ip_ratio=1.40 /
aq=1:1.00
Language : English
Default : No
Forced : No
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Original source medium : Blu-ray

Audio #1
ID : 2
ID in the original source medium : 4352 (0x1100)
Format : PCM
Format settings : Little / Signed
Codec ID : A_PCM/INT/LIT
Duration : 2 h 2 min
Bit rate mode : Constant
Bit rate : 2 304 kb/s
Channel(s) : 2 channels
Sampling rate : 48.0 kHz
Frame rate : 30.000 FPS (1600 SPF)
Bit depth : 24 bits
Stream size : 1.97 GiB (8%)
Title : Stereo
Default : Yes
Forced : No
Original source medium : Blu-ray

Audio #2
ID : 3
ID in the original source medium : 4353 (0x1101)
Format : DTS XLL
Format/Info : Digital Theater Systems
Commercial name : DTS-HD Master Audio
Codec ID : A_DTS
Duration : 2 h 2 min
Bit rate mode : Variable
Bit rate : 4 135 kb/s
Channel(s) : 6 channels
Channel layout : C L R Ls Rs LFE
Sampling rate : 48.0 kHz
Frame rate : 93.750 FPS (512 SPF)
Bit depth : 24 bits
Compression mode : Lossless
Stream size : 3.54 GiB (14%)
Title : Surround 5.1
Default : No
Forced : No
Original source medium : Blu-ray

Audio #3
ID : 4
ID in the original source medium : 4353 (0x1101)
Format : DTS
Format/Info : Digital Theater Systems
Codec ID : A_DTS
Duration : 2 h 2 min
Bit rate mode : Constant
Bit rate : 1 509 kb/s
Channel(s) : 6 channels
Channel layout : C L R Ls Rs LFE
Sampling rate : 48.0 kHz
Frame rate : 93.750 FPS (512 SPF)
Bit depth : 24 bits
Compression mode : Lossy
Stream size : 1.29 GiB (5%)
Title : Surround 5.1
Default : No
Forced : No
Original source medium : Blu-ray



I usually use staxrip with QTGMC filter to convert interlaced files, but I am lost with this one.

Here is a 11 second clip that demonstrates the issue:
https://drive.google.com/file/d/1Hzo4RgQpuSjkPOgQt3RdzC4Jsvh8Qsj7/view?usp=sharing

When using QTGMC, I see the following pattern starting e.g. from frame 146:
146: OK
147: OK but duplicate of 146
148: Ghosting
149: OK
150: Ghosting
151: OK
152: OK but Duplicate of 151
153: Ghosting
154: OK
155: Ghosting
156: OK
157: OK but Duplicate of 156
158: OK
159: OK but Duplicate of 158
160: Ghosting
161: OK
162: Ghosting
163: OK
164: OK but Duplicate of 163
165: Ghosting
166: OK
167: Ghosting
168: OK
169: OK but Duplicate of 168
170: OK
171: OK but Duplicate of 170
172: Ghosting
173: OK
174: Ghosting
175: OK
176: OK but Duplicate of 175
What is going on here and is it possible to fix it, preferably with staxrip avisynth or vapoursynth filters?
Thank you for your help!

[poisondeathray]

It's a typical field blended conversion from 25p to 29.97i


DGSource()
BWDIF(field=3)
SRestore(frate=25)

Use the avs version of srestore, because vapoursynth srestore post r54 has threading/cache problems producing mixed up frames

[-sTi-]

It's a typical field blended conversion from 25p to 29.97i


DGSource()
BWDIF(field=3)
SRestore(frate=25)

It looks perfect now in the preview, thank you! I will try a full encode later. I am a bit unsure how to best deal with the audio track, wouldn't it now be out of sync? What would you suggest in this case?

[poisondeathray]

I am a bit unsure how to best deal with the audio track, wouldn't it now be out of sync? What would you suggest in this case?

Use the same audio, it will be in sync. The duration is the same for the video before or after. 344 frames @ 30000/1001 or 287 frames @ 25/1 . Both are 11.440

[-sTi-]

Use the same audio, it will be in sync.
Perfect, thanks again!