Top field or bottom field

[dyanglp]

I downloaded TMPGEnc (listed in tool section of this site) and used the following method:

[/quote]Load your source and go to the advanced tab. Enable the deinterlace filter and double click on it. Set it to even/odd field (field) Now click on the slider and scroll through your movie frame by frame. If it jumps then your field order is incorrect. Go back to the advanced tab and change it. Check both ways to find which is smoothest, and then use that field order. Don't forget to disable the deinterlace filter when your done.

(It is from the thread: https://www.videohelp.com/forum/viewtopic.php?t=243537&highlight=tmpgenc+field )
But I didn't see difference no matter which field I selected. How can you manage to hold the slider and move frame by frame ? To me both fields are jumping. Is there any other way (software) that can help to determine field order ( for both avi & mpeg ) ?

Thanks.

[dyanglp]

Sorry it' messed up by the quote sign.

I downloaded TMPGEnc (listed in tool section of this site) and used the following method:

Load your source and go to the advanced tab. Enable the deinterlace filter and double click on it. Set it to even/odd field (field) Now click on the slider and scroll through your movie frame by frame. If it jumps then your field order is incorrect. Go back to the advanced tab and change it. Check both ways to find which is smoothest, and then use that field order. Don't forget to disable the deinterlace filter when your done.

(It is from the thread: https://www.videohelp.com/forum/viewtopi ... genc+field )
But I didn't see difference no matter which field I selected. How can you manage to hold the slider and move frame by frame ? To me both fields are jumping. Is there any other way (software) that can help to determine field order ( for both avi & mpeg ) ?

Thanks.

[adam]

You single click on the slider once. Then you can use the arrow keys on your keyboard to advance frame by frame. I'd have to look to confirm, and I'm too lazy, but I believe TMPGenc also has arrow buttons to advance a frame at a time.

You've tried changing between both field settings on the advanced tab and its jumpy either way? Then field order is not your problem, or at least not your only problem. Make sure that you are doing any unintended framerate conversions and if you are adjusting the framerate make sure you are doing it correctly. But if you aren't advancing frame by frame or playing the preview, but are rather just dragging the slider then I don't see how you can determine it is jumping. You need to view it in about real time or slower to be sure.

Also, just so you know...if your source is progressive then it will look the same regardless of what field order you set as there are no fields at all.

[lordsmurf]

Use GSPOT to verify field order. use 2.51 or newer.

[dyanglp]

Thank you both very much. I used an avi file captured from my DV camera to do this exercise on purpose and I know the correct field order is bottom first. I do see the arrow button but for any selection of the deinterlace filter, it gave me smooth moving (one frame at a time). The only thing I feel strange is that that filter now doesn' t have an option for odd-even field order (or something prevents it from being seeing ? ). I also used the avi file to preduce a mpeg-2 file with "top field first" and then did the same test but no difference being discovered. Maybe the current version no longer support what was doing before ?
BTW, Gspot seems only display field order for mpeg file, not avi file (?)

Any good reference for learning interlace/de-interlace ?

Thanks again.

[lordsmurf]

Do not deinterlace if this is for tv viewing.

[adam]

DV is a little different since its usually going to be pure interlaced, meaning that it is sampled completely in fields, as opposed to having something that was telecined which will have some frame pictures mixed in with fields. The result is that even with the wrong field order set, often the clip will still appear perfectly fine except during pans or otherwise difficult movement. So just for good measure, check again. Look in fast pans to see if you notice any visible interlacing. The motion itself should look normal.

Also when I say advance one frame at a time, I mean click on the slider and then hold the right keyboard button down. It will play slightly slower then real time, which is what you need to notice the effects of incorrect field order. Also another caveat, this method is not necessarily meant to be used to test field order generally, as not all programs correspond with each other (field order A may correspond to bottom field first in another encoder...retarded I know but true). This method basically shows you what you will get with your current TMPGenc field order settings. By selecting even/odd field (field), and yes you must select this filter not another, it merely makes the effects of incorrect field order more apparant.

When you advance one frame at a time in TMPGenc are you seeing whole frames with each advancement or are you seeing fields (combed picture)? If you are seeing frames with a DV source then it is not interlaced, and that would explain why the field order setting makes no difference. If this is the case the most likely cause is that you have your editor/capture device (p.s. Lordsmurf...I know capture is a misnomer with DV ) set to deinterlace or to otherwise only export progressive video. The other possibility is that your DV camera is set to progressive mode, but I'd assume you'd know if that was happening since you would have paid so much more for that feature.

[lordsmurf]

I wonder how it was transferred from camera to PC. You can screw up a file to have progressive headers, but the file is still interlaced. Makes a nice mess on screen. Easy to fix.

[dyanglp]

I did the test with another piece of captured video and yes, the interlacing is more visible when the field order is incorrect even though I have to watch it closely, it became more obvious when fast motion encounted. But frame jumping still didn't happen as I initialy expected, maybe the material being tested is not proper. The interesting thing is when encoding this avi file into two mpeg2 files with different field order settings, the difference seems disappeared (very hard to tell which one is which one).
Thanks again for the explaination.