how to tell up field first or down field first?

[george_zhu]

I captured 480x480 interlaced avi video with Virtual VCR from a Hi8 camcorder and would likt to encode it into SVCD by CCE. How can I tell whether it is up field first or down field first?

[RB]

Create the following AVISynth script:

AVISource("path_to_your_avi")
AssumeBFF().SeparateFields()

Play it in MediaPlayer 6.4. If movement is stuttery/jerky, it's Top Field first, otherwise it's Bottom Field first.

[bb]

You may of course double-check using this script:

AVISource("path_to_your_avi")
AssumeTFF().SeparateFields()

You could have found this through the search button, by the way ;)
:search:

bb

[wmansir]

If you're real lazy you can open TMPEGenc, Select the Project Wizard from the file menu, set the profile to NTSC (not NTSC film), click next and open your video source. It will automaticly detect the field order.

[Stabmaster-Arson]

restream will tell you as well. Also this method for non mpeg2 files.

Tools needed: tmpgenc


Selecting the correct field order:
Fire up tmpgenc then do this.
Press the "Settings" button and go to the "Advanced" tab. Under the "Field
order" setting, pick "Top field first (field A)". Highlight the
"DeInterlace" option in the list and double click it to open the DeInterlace
dialog. Select the "Even-Odd field (field)" Method. Left-Click on the video
area and then using the keyboard arrows move to the right to frame-advance
the video. If the motion is smooth, then the field order is correct, if it's
all jumpy then exit the DeInterlace dialog, switch the Field order to
"Bottom field first (field B)", re-enter the DeInterlace dialog and check
that now the movement is smooth. When the correct field order is selected,
make sure that the DeInterlace option is checked OFF! We only use it to
check the field order, it must not be enabled for the final encoding.

[bb]

Originally posted by Stabmaster-Arson
restream will tell you as well.[...]
ReStream reads the field order flag, which can have been set wrongly. The most reliable method is the AviSynth method described above, if you ask me.

bb

[Kika]

There's no need to burn a CD for testing. The AVISynth Scripts from bb and RB are enough to determine the correct Field order.

[bb]

Of course, if the AviSynth scripts tell you that your video is TFF, and you are funny enough to tell the encoder to encode BFF, then you'll run into problems...

bb

[rs008f]

Originally posted by wmansir
If you're real lazy you can open TMPEGenc, Select the Project Wizard from the file menu, set the profile to NTSC (not NTSC film), click next and open your video source. It will automaticly detect the field order.

I found out that TMPGEnc is not accurate at all. It reported some of my 23.976 fps Xvid/Divx videos as Interlace and BFF where it's actually PROGRESSIVE.