Problems with encoding interlaced (Pal) material

[influenza]

I used to deinterlace my DVD extras when reencding them because i was always dissatisfied by the results of interlaced encoding. But after a lot of reading about pros and cons I decided to give the interlaced encoding a serious try again. But again I have results that are not good and I don't quite get it.

I have used dif4u as usual and let it sort out the frametype etc. It comes out that my video is flagged as topfieldfirst, interlaced, alternate scanning order. This is also reported by bitrate viewer and dvd2avi also says interlaced, T(opfieldfirst).

So i encoded the video as being interlaced, and did not check top field first.

After playing the burned disc on my dvd player/TV the extras just play jerky. The motion is not smooth at all.

After that I decided to do a pulldown on all my mpv files. I inverted the fieldorder to bottom field first. (pulldown -nopulldown -tff even - framerate 25). After opening the mpv file in dvd2avi it now reports it as being B(ottom field first).

Recreated the dvd with the new files and burned again. NOW playback is smoothly! But i don't get why I should set the field order to bottom field first. (And I guess simply checking top field first for the extras in CCE is not enough)

[69Mws]

I personally never trust what dvd2avi or BR Viewer say.

The stream-diagnosis from DIF4U also often enough declared streams as interlaced although they were clearly progressive when looking at them in dvd2avi.

Last state was, that for some reason it can't be 100% determined for PAL sources.

I just check the stream in dvd2avi by scrolling a bit through it and see if I find interlaced combings.

That certainlay doesn't tell you, if the stream is bff- or tff-interlaced.

I read once about a method how to check for that in TMPGEnc, but I don't recall exactly how to do it.

It was something like opening your source in TMPGEnc and then doubleclicking the (de?)interlace-filter. There's a preview then and in this case you can set it to field odd or even and check there if it looks jerky/shaky in the preview and determine whether it's bff or tff.

Greetz
69Mws

[influenza]

Yes PAL sources are almost always flagged as being interlaced (main) while it's just progressive. Encoding the main as being interlaced doesn't matter though.

It's just those extras. those are clearly interlaced (only once had a progressive extra). It's just the field order that's hard to determine so it seems.

I heard of that tmpgenc method as well, but didn't know precisely how to do it. Will try that. Thanks.

[Boulder]

The field order in surprisingly easy to determine with a little help from an Avisynth script.

The following is from the Decomb tutorial, neuron2's text that is.

--
To determine the field order, make an Avisynth script that serves the raw clip without any processing. If it were an AVI, then just AviSource() would be used. For our examples, we'll use AviSource(). Add a script line to separate the fields using top field first, as follows:

AviSource("your_clip.avi")
AssumeTFF().SeparateFields()

Now serve the script into VirtualDub and find an area with motion. Single step forward through the motion. Note whether the motion progresses always forward as it should, or whether it jumps back and forth as it proceeds. For example, if the field order is wrong, an object moving steadily from left to right would move right, then jump back left a little, then move right again, etc. If the field order is correct, it moves steadily to the right.

If the motion is correct with AssumeTFF().SeparateFields(), then your field order is top field first. If the motion is incorrect, then your field order is bottom field first.
--

Since you're dealing with DVD sources, you would use MPEG2Source("your clip.d2v") .

[influenza]

Ah this is nice. Gonna try it when I get home.

Thanks :)

[69Mws]

Originally posted by Boulder
The field order in surprisingly easy to determine with a little help from an Avisynth script.

The following is from the Decomb tutorial, neuron2's text that is.

--
To determine the field order, make an Avisynth script that serves the raw clip without any processing. If it were an AVI, then just AviSource() would be used. For our examples, we'll use AviSource(). Add a script line to separate the fields using top field first, as follows:

AviSource("your_clip.avi")
AssumeTFF().SeparateFields()

Now serve the script into VirtualDub and find an area with motion. Single step forward through the motion. Note whether the motion progresses always forward as it should, or whether it jumps back and forth as it proceeds. For example, if the field order is wrong, an object moving steadily from left to right would move right, then jump back left a little, then move right again, etc. If the field order is correct, it moves steadily to the right.

If the motion is correct with AssumeTFF().SeparateFields(), then your field order is top field first. If the motion is incorrect, then your field order is bottom field first.
--

Since you're dealing with DVD sources, you would use MPEG2Source("your clip.d2v") .

Ah thx, this one's nice :)

Greetz
69Mws

[influenza]

Yes this works out nice. Guess you can also do it the other way around, so assume BFF instead of TFF.

AviSource("your_clip.avi")
AssumeBFF().SeparateFields()

And in doubt look at the same frames with the different settings.