FORUMS: list search recent posts

Field or pulldown problems when demuxing/transcoding PAL MPEG2s

COW Forums : DVD Authoring

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Matt Fish
Field or pulldown problems when demuxing/transcoding PAL MPEG2s
on Mar 12, 2013 at 10:25:49 pm

I've been re-authoring PAL DVDs to NTSC DVD for a few years now and have yet to come across this issue. I'm hoping one of you Creative Cow geniuses can help me figure this one out.

I received 4 PAL DVDs from a licensor in the UK (unfortunately tape masters or uncompressed files were unavailable). I used my usual standards-conversion from DVD workflow which worked fine for 3 of the discs. But on the 4th (one of the older titles) as soon as I opened it in MPEG Streamclip I noticed that the scan lines were more pronounced than usual and when I played it back it was "jerky". Playing back frame by frame (still in MPEG Streamclip) I noticed that it plays 6 frames and then the 7th frame is duplicated for frames 8 and 9 and then on frame 10 motion resumes.

Here is my workflow: Ripped the PAL DVD with MacTheRipper-->Opened .vob of main title in MPEG Streamclip and transcoded to ProRes 422 with original PAL dimensions, frame rate, and field settings-->Imported ProRes PAL file to FCP7 and dropped it in a sequence with NTSC frame size and rate and field dominance set to none. Then I dropped the Nattress G Converter (v2.5.2) filter on the clip in the sequence, set source pixel size to 720x576, source field order to upper, destination to upper (it doesn't give you an option to set these to "none"), High Quality downscaling checked, Progressive output checked, Deinterlace options set to Smart, tolerance=10, Anti-Alias=0, Motion Blur=100, pulldown offset =0.

These settings worked well for the first three but not on the fourth. Playback (as viewed on computer monitor and external CRT) was still "jerky". Thinking it could be an issue with MPEG Streamclip I bought Cinematize 3 and used that for the transcode to ProRes. When I first open the PAL MPEG2 in Cinematize it plays back but with serious artifacts every half second or so rather than playing several frames than freeze for a few as it did in MPEG Streamclip.

I've tried just about every combination of field settings at different stages in the process but still can't seem to fix it. I'm wondering if it could be this "Euro Pulldown" I've heard about to telecine 24 to 25 fps. Is it possible that the disc is actually 24 fps (since it's older it could have been shot on film) and then encoded at 24 fps with flags to add pulldown during playback on set top player to conform to 25 fps PAL (similar to what we do with 24p footage in NTSC-land)? Wild guess probably but grasping at straws here.

Sorry for such a long post but figured I'd include as much info as possible the first time around. Thanks in advance for any help you all might offer.

Matt


Return to posts index

Andreas Gumm
Re: Field or pulldown problems when demuxing/transcoding PAL MPEG2s
on Mar 12, 2013 at 11:47:02 pm

May the footage has been converted unconditionally from NTSC source to PAL before?

I'm curious what's behind. If you have a chance to upload some seconds for analysis, I would like to look into it.

Andreas


Return to posts index

Matt Fish
Re: Field or pulldown problems when demuxing/transcoding PAL MPEG2s
on Mar 14, 2013 at 7:38:49 pm

As far as I know this was never previously transcoded from NTSC to PAL. I will upload an excerpt from the PAL DVD. This is an h264 .mov that was transcoded using MPEG Streamclip.

The odd thing is that when you watch the original PAL DVD on a set-top player it looks fine. And playing back the ripped PAL VIDEO_TS with Apple's built-in DVD player or VLC it's fine. It's only when I try to open it in a program to transcode to ProRes (I've tried both MPEG Streamclip and Cinematize Pro 3) that the field and/or pull-down issues are visible.

sample:

http://reels.creativecow.net/film/pal-h264-sample-of-fieldpulldown-issue


Return to posts index


Andreas Gumm
Re: Field or pulldown problems when demuxing/transcoding PAL MPEG2s
on Mar 14, 2013 at 8:20:51 pm

Hi Matt,

your footage looks to be progressive!
If you want end up in NTSC MPEG2 for DVD, it would be really easy.
My Workflow would be as follows:
1. Encode the footage to MPEG2 720x480@25p
2. After that apply a pulldown 25p->29.97i (yes it works)
For applying pulldown to MPEG2 there is a little tiny tool called DGpulldown, but it's for PC.
May you find a Mac-Software doing the same?
After that you will get a NTSC stream @29.97 fps without speeddown.
Try it & let me know!

Andreas

Andreas Gumm
selfemployed media author


Return to posts index

Andreas Gumm
Re: Field or pulldown problems when demuxing/transcoding PAL MPEG2s
on Mar 14, 2013 at 10:34:01 pm

Hi Matt,

please forget my previous post.

My recommendation in the previous post works for clean 25p PAL sources only. Since I was looking to the clip with my smartphone I have thought you have posted the source clip. But it seems to be the resulting clip.

Can you upload a short MPEG2 clip (smart cutted from source) to a drop box account or any similar webspace?

Sorry for taking it wrong

Andreas Gumm
selfemployed media author

PS:
I'm not shure with your footage, but your assumption that an Euro-Pulldown may has been applied to the footage could be true. Pulldown process creates some repeated frames so a later deinterlacing by matching field of nearest neighbourhood could end up in similar results.


Return to posts index

Matt Fish
Re: Field or pulldown problems when demuxing/transcoding PAL MPEG2s
on Mar 15, 2013 at 3:25:02 pm

Hi Andreas,

Thanks for your suggestions. I tried uploading an excerpt of the original PAL MPEG2 but Creative Cow doesn't accept MPEG2 as a valid format for upload for some reason. So the clip I uploaded has been transcoded and doesn't accurately reflect the original which is actually interlaced top-field first.

If you give me your email I will send you an invite to my dropbox account where I have put another clip, this one a straight demux of the PAL DVD. Thanks!

Matt


Return to posts index


Andreas Gumm
Re: Field or pulldown problems when demuxing/transcoding PAL MPEG2s
on Mar 15, 2013 at 7:55:03 pm

You can add me to your DropBox with the following adress:
andreas(point)gumm(at)gmx(point)de

Andreas Gumm
selfemployed media author


Return to posts index

Matt Fish
Re: Field or pulldown problems when demuxing/transcoding PAL MPEG2s
on Mar 15, 2013 at 8:09:36 pm

Okay, you should receive an invite from Dropbox to view the Video Samples folder. Thanks again!


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]