vob to mp4 seems to mess up interlacing?

[patrick99e99]

I have a DVD, if I play the .VOB file directly in VLC, with the option "automatic" set for deinterlace. Then the picture looks great. However, if I convert that .VOB to a .mp4 with:

ffmpeg -i out.vob converted.mp4

Then when I view the mp4 in VLC, with that same "automatic" option, it looks like it's not being deinterlaced and there are awful horizontal lines everywhere. If I change the option for deinterlace in VLC to "on" then the picture looks smooth...

It appears that some how when I am converting this to mp4, some metadata is getting lost and video players think they don't need to deinterlace... I originally was converting that mp4 to m2v and burning that to DVD, and noticing on my bluray player when watching, it had all those horrible horizontal lines.

When I look at the .VOB metadata, I see:

Input #0, mpeg, from 'out.vob':
  Duration: 00:46:58.69, start: 3697.324300, bitrate: 6093 kb/s
  Stream #0:0[0x80]: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
  Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, smpte170m, bottom first), 720x480 [SAR 8:9 DAR 4:3], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc

I see it says "Bottom first" which I assume is what makes VLC know "automatic" should be deinterlacing?

When I look at the metadata for the converted mp4 file:

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'converted.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.76.100
  Duration: 00:46:58.82, start: 0.000000, bitrate: 1710 kb/s
  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, smpte170m), 720x480 [SAR 8:9 DAR 4:3], 1573 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]
  Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      vendor_id       : [0][0][0][0]

I don't see anything about field ordering...... Is there some flag I should be setting when converting to mp4?

[poisondeathray]

For libx264 , bff

-x264opts bff=1