Clean Compress to DV NTSC Anamorphic?

Shaun Roemich · July 5th, 2009, 10:55 AM

Quote:

Originally Posted by Robert Rogoz

Say you shoot 720p. That's 720 lines of horizontal resolution and every field is scanned whole. Now you downsize it to 480i (That's what DV NTSC is). Not only you drop pretty much every third line, but also you show only even and odd lines in each frame.

Robert: I should have been more clear: I downloaded the clip and used the methodology that I use for my HD200U 720P60 footage (which works VERY well for me) and the artifacting and moiré was AWFUL. Sorry if I wasn't clear. MY experience with MY 720P footage is VERY different.

Robert Rogoz · July 6th, 2009, 12:48 PM

I did run some tests. I downloaded raw samples posted some time ago by Tim. I used both Compressor and Quicktime Conversion Export App. with exact same results. I used straight export and 2 stage export. In all samples I had the same ugly results.
I don't know if this is the cause, but in the settings there is only DV/DVCPRO NTSC, not DV NTSC. It might be something Apple has to fix with a patch.

Sean Adair · July 7th, 2009, 01:37 PM

Quote:

Originally Posted by Robert Rogoz

I did run some tests. I downloaded raw samples posted some time ago by Tim. I used both Compressor and Quicktime Conversion Export App. with exact same results. I used straight export and 2 stage export. In all samples I had the same ugly results.
I don't know if this is the cause, but in the settings there is only DV/DVCPRO NTSC, not DV NTSC. It might be something Apple has to fix with a patch.

DV & DVCPRO (25) are the exact same compression codec (so is DVCAM)
"DV NTSC" is a setting in compressor (under "Standard definition"). You can make (and save) your own modifications to this for progressive/ 24or30P/16:9 anamorphic etc.
When resizing from HD, you would definitely want resizing set to best. There are quite a few tweaks to look at, and I'm not clear what has been tried so far. Will try to play with the 3 sec clip when I get a chance. Moire is a tricky phenomena though, resulting from a mathematical interplay of horizontal lines. Reducing resolution can improve footage in some cases - counter to intuition.
Donald - sorry about the DVD conversion confusion. That was me in an early post not reading carefully. Probably propagated more confusion.
Mpegstreamclip has been really useful for me in the past, but it's a bear of a workflow. I had big problems with it's conversion dropping frames and sync at one stage, and then had fantastic fast results within FCP using the "Media Manager" tool. That's what I'd be trying first - ideal for converting an entire edited project or raw footage in the timeline.

Bob Richardson · July 7th, 2009, 01:53 PM

I wanted to chime in here about my past experience... I haven't had a chance to look at the current footage and do a test, but...

The one time I had to convert HD 1080p30 to DV for a client, using QuickTime, the results were horrible, way worse than anything I ever shot in native DV. This was using a Canon HF-100 camcorder (AVCHD format on SDHC cards).

What _appeared_ to be happening is that the 1080p progressive footage was being converted to DV 480i by subsampling the same lines from the 1080p frame for _both_ 480i fields. This resulted in an effective 240 lines of resolution, rather than 480, and caused jagged lines and "moire" effects to appear all over the place.

My solution at the time was simple: Provide the client with alternative formats -- Thankfully, the client was fine with this and had only been asking for DV as a matter of habit.

By the way, the same footage converted to Standard Def as a DVD using iDVD came out just fine. There's just something wrong (in my opinion based on anecdotal experience) in the default assumptions QuickTime makes when converting from high definition to DV.

William Hohauser · July 7th, 2009, 02:51 PM

It really does look like an error in the conversion where 1 field of an interlaced frame is being repeated. As I've never had this problem with 720p footage it's possibly a software bug in the conversion architecture that FCS uses. If MPEGStreamclip does it right then I suggest making QuickTime Movies (uncheck "Make Self-Contained") of your finished projects and make the down-conversion that way until an update fixes the problem.

David Walton · July 14th, 2009, 09:03 AM

Now, when is SOMEBODY going to download my 3-second clip, use Compressor with the DV NTSC setting, and report back?[/QUOTE]

--------------------------------
Donald,

I downloaded your clip. I used WinFF (front end for FFMPEG) to convert it to DV and got a clean conversion using the presets. WinFF is free, and can be found at WinFF - Free Video Converter. It's available for Linux and Windows.

David Walton
JVC

July 6th, 2009, 12:48 PM	#32
Robert Rogoz Major Player Join Date: Sep 2007 Location: Bellingham, WA Posts: 457	Several tests I did run some tests. I downloaded raw samples posted some time ago by Tim. I used both Compressor and Quicktime Conversion Export App. with exact same results. I used straight export and 2 stage export. In all samples I had the same ugly results. I don't know if this is the cause, but in the settings there is only DV/DVCPRO NTSC, not DV NTSC. It might be something Apple has to fix with a patch.

July 7th, 2009, 01:53 PM	#34
Bob Richardson Regular Crew Join Date: Mar 2009 Location: Portland, OR Posts: 178	I wanted to chime in here about my past experience... I haven't had a chance to look at the current footage and do a test, but... The one time I had to convert HD 1080p30 to DV for a client, using QuickTime, the results were horrible, way worse than anything I ever shot in native DV. This was using a Canon HF-100 camcorder (AVCHD format on SDHC cards). What _appeared_ to be happening is that the 1080p progressive footage was being converted to DV 480i by subsampling the same lines from the 1080p frame for _both_ 480i fields. This resulted in an effective 240 lines of resolution, rather than 480, and caused jagged lines and "moire" effects to appear all over the place. My solution at the time was simple: Provide the client with alternative formats -- Thankfully, the client was fine with this and had only been asking for DV as a matter of habit. By the way, the same footage converted to Standard Def as a DVD using iDVD came out just fine. There's just something wrong (in my opinion based on anecdotal experience) in the default assumptions QuickTime makes when converting from high definition to DV. Last edited by Bob Richardson; July 7th, 2009 at 03:42 PM.

July 7th, 2009, 02:51 PM	#35
William Hohauser Inner Circle Join Date: Dec 2005 Location: New York City Posts: 2,650	It really does look like an error in the conversion where 1 field of an interlaced frame is being repeated. As I've never had this problem with 720p footage it's possibly a software bug in the conversion architecture that FCS uses. If MPEGStreamclip does it right then I suggest making QuickTime Movies (uncheck "Make Self-Contained") of your finished projects and make the down-conversion that way until an update fixes the problem. __________________ William Hohauser - New York City Producer/Edit/Camera/Animation

July 14th, 2009, 09:03 AM	#36
David Walton JVC Join Date: Feb 2006 Posts: 13	Now, when is SOMEBODY going to download my 3-second clip, use Compressor with the DV NTSC setting, and report back?[/QUOTE] -------------------------------- Donald, I downloaded your clip. I used WinFF (front end for FFMPEG) to convert it to DV and got a clean conversion using the presets. WinFF is free, and can be found at WinFF - Free Video Converter. It's available for Linux and Windows. David Walton JVC