[HELP] About deinterlace, telecine and other things

[Doom83]

In my journey to convert some movies, i use some command on ffmpeg for analyze the video frame and sometime give strange things


 

Duration: 00:27:25.41, start: 1696.428300, bitrate: 6349 kb/s
  Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, fcc/bt470bg/bt470bg, bottom first), 720x480 [SAR 8:9 DAR 4:3], 29.97 fps, 29.97 tbr, 90k tbn, start 1696.661633
    Side data:
      cpb: bitrate max/min/avg: 8800000/0/0 buffer size: 1835008 vbv_delay: N/A
  Stream #0:1[0x80]: Audio: ac3, 48000 Hz, mono, fltp, 192 kb/s, start 1696.428300
[Parsed_idet_0 @ 000001de269c8cc0] Repeated Fields: Neither:    0 Top:    0 Bottom:    0
[Parsed_idet_0 @ 000001de269c8cc0] Single frame detection: TFF:    0 BFF:    0 Progressive:    0 Undetermined:    0
[Parsed_idet_0 @ 000001de269c8cc0] Multi frame detection: TFF:    0 BFF:    0 Progressive:    0 Undetermined:    0
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video (native) -> wrapped_avframe (native))
Press [q] to stop, [?] for help
Output #0, null, to 'pipe:':
  Metadata:
    encoder        : Lavf62.3.100
  Stream #0:0: Video: wrapped_avframe, yuv420p(tv, fcc/bt470bg/bt470bg, bottom coded first (swapped)), 720x480 [SAR 8:9 DAR 4:3], q=2-31, 200 kb/s, 29.97 fps, 29.97 tbn
    Metadata:
      encoder        : Lavc62.11.100 wrapped_avframe
[Parsed_idet_0 @ 000001de26daf880] Repeated Fields: Neither:  501 Top:    0 Bottom:    0
[Parsed_idet_0 @ 000001de26daf880] Single frame detection: TFF:    0 BFF:    0 Progressive:  448 Undetermined:    53
[Parsed_idet_0 @ 000001de26daf880] Multi frame detection: TFF:    0 BFF:    0 Progressive:  495 Undetermined:    6
[out#0/null @ 000001de269c7e00] video:203KiB audio:0KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: unknown
frame=  500 fps=0.0 q=-0.0 Lsize=N/A time=00:00:16.68 bitrate=N/A speed= 294x elapsed=0:00:00.05

Tell chatgpt and say there are interlaced BFF but with a lot of progressive frames and undetermined  
Put in hybrid and say is TFF

how handle this?

[Selur]

Don't trust such automated analysis results, read [INFO] Interlacing patterns and figure out whether the source is telecined, interlaced (tff or bff), field shifted, progressive or a mix of everything.

Flags can be wrong, heuristics are often wrong, without a sample with horizontal motion the source might be telecined.

Cu Selur

[Doom83]

So need to watch frame by frame in external player like vlc? In in the player inside hybrid?
On hybrid in a clip with bob I see A B A BB A B A BB A B A BB and so on....without bob I se AAAA B AAAA B AAAA B....

[Selur]

So need to watch frame by frame in external player like vlc? In in the player inside hybrid?

Using the Vapoursynth Preview should be fine.
The rest is written down in the linked thread.

I see A B A BB A B A BB A B A BB and so on....without bob I se AAAA B AAAA B AAAA B....

What ?
No clue what you want to communicate with that. No clue what A and B should represent.

Cu Selur

Ps.: I can look at it if you can share a link to a small (unprocessed) sample of the source.

[Doom83]

sorry, wanna say A is good frame, b is freezed frame 
so  forward  stop  forward stop  stop

[Selur]

"forward stop forward stop stop "
so from a cycle of 5 you would keep just 0 and 2.
So I would use TIVTC with mode 7 and a target frame rate of 23.976 and if that does not work properly you could.
1. Bob deinterlacing with QTGMC
2. Use SelectEvery with a cycle of 5 and '0 2' as frames to keep

Cu Selur