What causes stepping artifact in video?

Hi Everyone. Happy Holidays!

I'm working with source footage from DVD masters. I use MPEG Streamclip to extract the media using the Apple Pro Res 422 codec at medium quality. After editing I export a full quality QT file and bring into Compressor to make a Youtube file using the Compressor Youtube preset. I have used this work flow over and over and never had the problem with quality I'm experiencing with my current project. I'm getting these "stepping" artifacts where ever there is movement. I've tried forcing compression markers and using a frame blend filter but no luck.

The sequence settings are as follows: Frame Size - 720 x 480, AR - NTSC DV 3:2, Pixel AR - NTSC-CCIR601/DV. Field Dominance: Lower (Even), Editing Timebase - 29.97, QT Video Settings, Compressor: DV/DVCPRO - NTSC, Quality 100%

Can you tell me what may be happening and how I can fix this?

Thanks a lot.

Shelley

Shelley
MacBoo Pro 2015
16 GB Ram
OS X 10.13
Premiere Pro CC

A DVD "master" is never going to look too hot. You're taking an SD source, compressing the heck out of it in MPEG-2 for the DVD, and then re-extracting that MPEG-2 for a further layer of heavy compression (ProRes). But then, why are you editing in a DV NTSC timeline? That adds yet another huge hit.


www.derekmok.com

derekmok Wrote:
-------------------------------------------------------
> A DVD "master" is never going to look too hot.
> You're taking an SD source, compressing the heck
> out of it in MPEG-2 for the DVD, and then
> re-extracting that MPEG-2 for a further layer of
> heavy compression (ProRes). But then, why are you
> editing in a DV NTSC timeline? That adds yet
> another huge hit.

Ditto.....

Walter Biscardi, Jr.
Biscardi Creative Media
biscardicreative.com

Yes I understand the quality and compounding compression issues using DVD masters but that's all the client has to work with and I need the money so I'm doing the job.

I don't understand why the sequence setting doesn't default to the Apple Pro Res compression when I drop it in the timeline. I though FC adjusts. Do I need to manually change the compression in the sequence setting to Pro Res before dropping in the Pro Res clip?

I still don't understand why I'm getting the stepping or how to fix it? It's not like that on the DVD and I have extracted media from other DVDs without winding up with the stepping problem.

Do you know anything I can try to fix it?

Thanks

Shelley
MacBoo Pro 2015
16 GB Ram
OS X 10.13
Premiere Pro CC

shelleyrae Wrote:
------------------------------------------------------->
> I still don't understand why I'm getting the
> stepping or how to fix it? It's not like that on
> the DVD and I have extracted media from other DVDs
> without winding up with the stepping problem.
>
> Do you know anything I can try to fix it?
>
> Thanks

Not all DVDs are created equal. The original quality of the video from the DVDs you received is wholly dependent on the quality of the original video and then how it was compressed for the DVD. You are probably starting off with DVD quality that is much worse than you are used to working with, so the compression is much higher.

The stepping is coming from all the compression and recompression. In very simple terms, when video is compressed, it's turned into square blocks. The better the compression, the less you see of the blocks. The worse the compression or the more times the video is recompressed, the more you see of the blocks which are obvious as "stair stepping."

Now you take the MPEG-2 video that was created for the DVD (it's in blocky squares), and now use MPEG-Streamclip to recompress that video to ProRes (blocky squares made into new blocky squares) and drop that into a DV timeline (blocky square that were made into blocky squares now made into new DV blocky squares) and you have triple video compression.

THAT's why you're getting the stepping and there's no real way to get rid of it without getting better original quality video.

As for FCP's Sequence Settings, you create a New Sequence. Now Drag a clip to the Sequence. FCP asks you if you'd like to create a new sequence based on the Clip. Say "Yes."

Walter Biscardi, Jr.
Biscardi Creative Media
biscardicreative.com

> I don't understand why the sequence setting doesn't default to the Apple Pro Res compression when I drop it in
> the timeline. I though FC adjusts.

FCP won't ask that question if you already have clips in the timeline that do match the Sequence Settings.

You shouldn't be relying on that anyway. As an editor, you should know what your Sequence Settings are. A nice quick way to ensure new Sequences have the same specs as older, correct Sequences is to duplicate a pre-existing Sequence, rather than using the New Sequence command.


www.derekmok.com

Thanks for the feedback Derek and Walter.

When I play the DVD so called "master" I don't see the stepping. It actually looks pretty good. What if I recorded the DVD to a digital tape and then captured the footage from the tape. Do you think that would work?

Shelley
MacBoo Pro 2015
16 GB Ram
OS X 10.13
Premiere Pro CC

shelleyrae Wrote:
-------------------------------------------------------
> Thanks for the feedback Derek and Walter.
>
> When I play the DVD so called "master" I don't see
> the stepping. It actually looks pretty good. What
> if I recorded the DVD to a digital tape and then
> captured the footage from the tape. Do you think
> that would work?

You're still going to do the multiple compressions. when you capture from the tape, you will have to compress it again to ProRes or DV or whatever during capture.

Each time you recompress, you add more "blockiness" and then you see the stepping.

Of course putting the original footage you have into a proper ProRes sequence might help a little.

Walter Biscardi, Jr.
Biscardi Creative Media
biscardicreative.com

I'm going to add one point to the discussion- interlacing.

From the description of the problem, where the "blockiness" happens when there is movement, my assumption is that the source footage is interlaced. If your source is interlaced, you need to deinterlace it before you do your final compression for web, or the web compression will do nasty things to the video.

The built in Apple DVD player deinterlaces the image for the computer screen and plays back the video at field rate, which is similar to how LCD TVs play back interlaced footage since they do not use scan guns to produce video fields. This is distinctly different from how FCP plays back the video in the FCP canvas, which if resized, discards one field and plays back the image at frame rate.

What you can do is to pop the DVD into Mpeg streamclip, hit apple I for the inspector and check the frame rate and if it is interlaced. Then export as Uncompressed (yes, I use Uncompressed when I work with DVD "masters" from clients) and make sure the video is unscaled. Your video should be 720x576 if you are in the PAL region or 720x480 if you are in the NTSC region.

If the DVD was made in North America, open that clip in QuickTime and step through 5 frames to see if the DVD was 23.976 progressive, or if a pulldown was added, or if it is interlaced 29.97. If there is a pulldown (you get one or two interlaced frames and some progressive frames in the 5 frames with movement), remove the pulldown with Cinema Tools or with the free JES Deinterlacer. Then import the deinterlaced footage into FCP. If the footage is interlaced 29.97, edit in an Uncompressed timeline set to 720x480 (for NTSC rates), then when you are done with the edit, export a SCQT and encode that in Compressor with Frame Controls turned on and set output fields to progressive and set deinterlace to better or best. "best" will take an eternity to encode, but it usually looks pretty damned good.



www.strypesinpost.com

If I am forced to re-edit a DVD, I always ensure I go to the timeline with ProRes,
so at least it will mitigate some of the generation loss.

But DVD to a DV timeline is a sure way to end up dissapointed!



derekmok Wrote:
-------------------------------------------------------
> > I don't understand why the sequence setting
> doesn't default to the Apple Pro Res compression
> when I drop it in
> > the timeline. I though FC adjusts.
>
> FCP won't ask that question if you already have
> clips in the timeline that do match the Sequence
> Settings.
>
> You shouldn't be relying on that anyway. As an
> editor, you should know what your Sequence
> Settings are. A nice quick way to ensure new
> Sequences have the same specs as older, correct
> Sequences is to duplicate a pre-existing Sequence,
> rather than using the New Sequence command.