Every 12th frame... at DVinfo.net

James Klatt · June 21st, 2007, 12:50 PM

Okay, I have a wedding ceremony that is like 20 minutes long. After using an Mpeg-2 Highest Quality (60 minutes) encode I have the following problem. The whole video looks great up until about the 15:40 mark. At this point every 12th frame of my 23.98 progressive footage has a digitized mosaic-y look. THe weird thing is that eventually gets to the point where it is every frame artifacty. This all happens for about a minute then suddenly everything is back to normal. I tried re-encoding to no avail.

The original footage is fine, so its not the camera or tape.To make things more interesting, in my edit I am cutting between two different cameras and the effect happens on both cameras footage during this time 15:40 to 16:50 time period.

There are no effects or transitions used. Also it should be noted that my workflow has been perfect for my first 2 projects.

ADDITION - I tried just encoding the 15:40-16:60 segment as a separate clip in compressor and it works fine, so I really don't know what to do.

Alan James · June 21st, 2007, 01:42 PM

What editing program did you use? It might help for us to know. I assume Final Cut but u never know.

James Klatt · June 21st, 2007, 02:52 PM

Final Cut Studio 2.

I am at my wit's end. I am assuming it has something to do with encoding to Mpeg-2 and the GOP structure. Before I encoded to Mpeg 2 in compressor, I output my HDV edit to ProRes HQ. The ProRes version looks fine...

I am pulling my hair out. Especially since I have gotten other DVDs to work with this procedure.

Chris Barcellos · June 21st, 2007, 03:05 PM

What cameras ? Is it possible they were shooting at different frame rates ?

Greg Boston · June 21st, 2007, 04:18 PM

Quote:

Originally Posted by James Klatt

Final Cut Studio 2.

I am at my wit's end. I am assuming it has something to do with encoding to Mpeg-2 and the GOP structure. Before I encoded to Mpeg 2 in compressor, I output my HDV edit to ProRes HQ. The ProRes version looks fine...

I am pulling my hair out. Especially since I have gotten other DVDs to work with this procedure.

James, sometimes files get corrupted in the timeline and do strange things like this. I have read instances from our local FCP list server and sometimes it's a matter of trashing the existing sequence and rebuilding it. Since you don't have a lot going on there according to your post, it wouldn't take long to reconstruct.

-gb-

James Klatt · June 21st, 2007, 04:24 PM

I used an HV20 and an XH-A1 both shot 24fps. With the HV20 worklow, I had to encode to ProRes so I could edit on the same timeline with the Xh-A1 footage.(Even though the HV20 shoots at 24fps, it captures as 29.97 interlaced...I think its kinda like how you can shoot 24 with the DVX100a and edit on the 29.97 timeline).

Anyway, I edited between 23.976 HDV and 23.976 ProRes and exported the whole file as a 23.976 ProRes HQ file.

The ProRes file looks perfect the whole way through.

I then used the 23.976 ProRes file in compressor and encoded it to the Mpeg-2 Highest Quality Anamorphic (60 minutes).

I wouldn't feel so confused if the macroblockiness was consistent the whole way through the footage. But it's not. It only happens at the 16 minute mark and last about a minute and then goes away.

Another confusing thing is how if I cut out that 1 minute sequence from my timeline (that exhibits the macroblocking) and export as a ProRres file and THEN encode in compressor it looks fine.

Another note about the macroblockiness is that it gets worse as that minute goes along.

James Klatt · June 21st, 2007, 04:36 PM

Greg,

The exported footage from the timeline looks perfect. It the compressor outputted footage that is ugly.

I'll try anything though. Could you explain to me how I would "rebuild" the old sequence into a new one. I have tons of cuts between the 2 cameras and I also have an extra audio source from a field recorder.

Cole McDonald · June 21st, 2007, 04:44 PM

if there are options for the mpeg conversion for keyframe...set it to 1. The keyframe in this case is when the picture refreshes fully...between keyframes, it just changes regions of the image being displayed.

This may help. or not. I'm not committing to this as a solution, just a possibility.

Chris Barcellos · June 21st, 2007, 04:55 PM

Quote:

Originally Posted by James Klatt

I used an HV20 and an XH-A1 both shot 24fps. With the HV20 worklow, I had to encode to ProRes so I could edit on the same timeline with the Xh-A1 footage.(Even though the HV20 shoots at 24fps, it captures as 29.97 interlaced...I think its kinda like how you can shoot 24 with the DVX100a and edit on the 29.97 timeline).

Anyway, I edited between 23.976 HDV and 23.976 ProRes and exported the whole file as a 23.976 ProRes HQ file.

The ProRes file looks perfect the whole way through.

I then used the 23.976 ProRes file in compressor and encoded it to the Mpeg-2 Highest Quality Anamorphic (60 minutes).

I wouldn't feel so confused if the macroblockiness was consistent the whole way through the footage. But it's not. It only happens at the 16 minute mark and last about a minute and then goes away.

Another confusing thing is how if I cut out that 1 minute sequence from my timeline (that exhibits the macroblocking) and export as a ProRres file and THEN encode in compressor it looks fine.

Another note about the macroblockiness is that it gets worse as that minute goes along.

The reason I askded about frame rate issues is because I've seen the same thing on the PC side, with the HV20. To be clear, when you process the HV20 stuff in ProRes, is it removing pull down for you ? In my case, I use Cineform to remove pulldown, so the footage becomes true 24p, I assume that is what you expect you are getting in ProRes, right ?

June 21st, 2007, 12:50 PM	#1
James Klatt Regular Crew Join Date: Dec 2002 Location: Portland OR Posts: 132	Every 12th frame... Okay, I have a wedding ceremony that is like 20 minutes long. After using an Mpeg-2 Highest Quality (60 minutes) encode I have the following problem. The whole video looks great up until about the 15:40 mark. At this point every 12th frame of my 23.98 progressive footage has a digitized mosaic-y look. THe weird thing is that eventually gets to the point where it is every frame artifacty. This all happens for about a minute then suddenly everything is back to normal. I tried re-encoding to no avail. The original footage is fine, so its not the camera or tape.To make things more interesting, in my edit I am cutting between two different cameras and the effect happens on both cameras footage during this time 15:40 to 16:50 time period. There are no effects or transitions used. Also it should be noted that my workflow has been perfect for my first 2 projects. ADDITION - I tried just encoding the 15:40-16:60 segment as a separate clip in compressor and it works fine, so I really don't know what to do.

June 21st, 2007, 03:05 PM	#4
Chris Barcellos Inner Circle Join Date: Nov 2005 Location: Elk Grove CA Posts: 6,838	What cameras ? Is it possible they were shooting at different frame rates ? __________________ Chris J. Barcellos

June 21st, 2007, 04:44 PM	#8
Cole McDonald Trustee Join Date: Nov 2005 Location: Sauk Rapids, MN, USA Posts: 1,675	if there are options for the mpeg conversion for keyframe...set it to 1. The keyframe in this case is when the picture refreshes fully...between keyframes, it just changes regions of the image being displayed. This may help. or not. I'm not committing to this as a solution, just a possibility. __________________ Web Youtube Facebook

June 21st, 2007, 01:42 PM	#2
Alan James Regular Crew Join Date: Jul 2006 Location: Tampa, Florida Posts: 261	What editing program did you use? It might help for us to know. I assume Final Cut but u never know.

June 21st, 2007, 02:52 PM	#3
James Klatt Regular Crew Join Date: Dec 2002 Location: Portland OR Posts: 132	Final Cut Studio 2. I am at my wit's end. I am assuming it has something to do with encoding to Mpeg-2 and the GOP structure. Before I encoded to Mpeg 2 in compressor, I output my HDV edit to ProRes HQ. The ProRes version looks fine... I am pulling my hair out. Especially since I have gotten other DVDs to work with this procedure.

June 21st, 2007, 04:24 PM	#6
James Klatt Regular Crew Join Date: Dec 2002 Location: Portland OR Posts: 132	I used an HV20 and an XH-A1 both shot 24fps. With the HV20 worklow, I had to encode to ProRes so I could edit on the same timeline with the Xh-A1 footage.(Even though the HV20 shoots at 24fps, it captures as 29.97 interlaced...I think its kinda like how you can shoot 24 with the DVX100a and edit on the 29.97 timeline). Anyway, I edited between 23.976 HDV and 23.976 ProRes and exported the whole file as a 23.976 ProRes HQ file. The ProRes file looks perfect the whole way through. I then used the 23.976 ProRes file in compressor and encoded it to the Mpeg-2 Highest Quality Anamorphic (60 minutes). I wouldn't feel so confused if the macroblockiness was consistent the whole way through the footage. But it's not. It only happens at the 16 minute mark and last about a minute and then goes away. Another confusing thing is how if I cut out that 1 minute sequence from my timeline (that exhibits the macroblocking) and export as a ProRres file and THEN encode in compressor it looks fine. Another note about the macroblockiness is that it gets worse as that minute goes along.

June 21st, 2007, 04:36 PM	#7
James Klatt Regular Crew Join Date: Dec 2002 Location: Portland OR Posts: 132	Greg, The exported footage from the timeline looks perfect. It the compressor outputted footage that is ugly. I'll try anything though. Could you explain to me how I would "rebuild" the old sequence into a new one. I have tons of cuts between the 2 cameras and I also have an extra audio source from a field recorder.