EX1 footage to DVD - Blockyness on long encodes?

Chadfish

Chadfish

Veteran
Here's a scenario I want to check with others about. The method described below is how I usually encode files for DVD in DVD Studio Pro. It usually results in awesome looking DVDs that play at true 16x9, rather than letterboxed NTSC. Maybe my method is not the best? All I know is it works on short encodes, but on an 80 minute file I got some strange artifacts. Please let me know if you have experiences this, or if you have another method for authoring DVDs in DVD studio pro from EX1 footage. I find that just dropping a file into iDVD results in lots of aliasing unless the file is NTSC to begin with.


I'm on 10.4.11 on an 8 Core MacPro.

I shot about 80 min of interview footage at 1080/30p on my EX1. Captured fine. Edit slightly, color correct, and encode one large full quality file at 1080/30p. Looks fine. I go to compressor and encode a MPEG-2 6.2Mbps 2-Pass & a Dolby Digital Pro 2.0 audio at 192kbps. I usually put these into a simple, one menu DVD Studio Pro project that plays fine, and looks great upscaled on my 46" Sony Bravia HDTV..

Upon viewing the DVD in simulation mode, about 10-15 min into the file I start getting a blockyness. It happens in a pulse like clear/blocky/clear/blocky/clear, switching every half second and lasting for a few minutes. This happens 2 or 3 times throughout the 80 minutes.

I tried making another master file at 720/30p. Same thing on Mpeg-2 encode.

Made a short file (720/30p) at the exact place where the blockyness occurrs, then encode for DVD and it doesn't happen. It seems that the long length of the file has something to do with the blockyness. It's VERY annoying because I need to make a DVD of these interviews for a client, and the method I use usually results in the best looking 16x9 image to DVD, coming from EX1 footage. Like I said, it isn't happening for me on shorter encodes.

How are you dealing with your EX1 footage as far as making DVDs? Have you experienced anything like I described?

Thank you.

Chad
 
While I am not on a Mac, there are a few things I would look at.

1. Could you define what you mean by "captured" fine? There should be no capture for these. Just a file copy.

2. When you say you "encode one large full quality file", what codec are you encoding with? ProRes? Can you play the file out on your computer at this step and verify that the blockyness isn't in the footatge at this point?

3. Once you create your mpeg2 file, can you view that file on the computer before you commit it to DVD? Is that where you start to see the blockyness? Does it show up if you actually cut the DVD and play that back?

It sounds like your encoder is getting overwhelmed. Maybe try pushing your encoding rate up to 7.5 Mb/s since you're only using 192kbps audio. See if that makes a difference.
 
Hey Perrone

1. Captured: An antiquated term I still use from my MiniDV days. I do a XDCAM Transfer of all my footage now.

2. I encode files at the same settings as the original files. So I'll edit my timeline how I like, then export either an XDCAM 1080/30p OR 720/30p. These files play back fine with no artifacts.

3. Like I said, it shows artifacts in DVD simulation mode. But I didn't say that it also shows when I burn a DVD, AND it also shows when I click on the file in my finder and play the file in preview. It's happening somewhere in the Mpeg-2 encode, and it's related to the length of the original file.

I will try pushing my encode rate up. I just don't understand why the length of a file should matter. I will report back on this later as I am on another project right now. But please anyone else chime in on their experience with this. I hope it's as simple as Perrone's solution. Thanks man.
 
No problem. However, you do realize that step 2 of your workflow is lossy... right? Not saying that is causing your problem, as from your comments, it isn't. But it's a quality hit you might not need to take.
 
PerroneFord said:
No problem. However, you do realize that step 2 of your workflow is lossy... right? Not saying that is causing your problem, as from your comments, it isn't. But it's a quality hit you might not need to take.
Click to expand...

Well fu@# me...

OK man, please drop the knowledge. How can I deal with my files day-in day-out without getting too crazy on the file size.

Here's my flow: In cam - 1080/30p or 720/30p. Capture XDCAM same. Edit/filters/color correct (Not in Color - just 3-way). Render final file same as project settings.

For TV I drop the XDCAM sequence into an NTSC timeline and export NTSC file, or bounce to tape.


Please help me clean my flow up!

Chadfish
 
OK,

Dropping XDCam onto your timeline is probably ok. Depending on how much filtering and coloring you are doing, you might be stressing that codec beyond it's limits. This is why you see many folks going to 10-bit codecs on the timeline. ProResHQ/DNxHD and similar are excellent for this.

It's the next render to your final that's the tricky bit. XDCam is lossy. So when you are making your master, you really want to do that to something that is going to be lossless or near lossless. Options here include Uncompressed, ProRes, DNxHD, CineformHD, etc.

Essentially, what I recommend is if you are going to be doing anything more than just simple cuts and an export, bring the data into your timeline with a better codec. One that can stand up to multigenerational renders without falling down. That way, you preserve more of what you started with.

There are a number of methodologies out there for workflow. I tend to try to get as high a quality codec on the timeline as I can (unless I am doing a proxy workflow) so that I can do what I need to do without worrying about generational loss. My personal choice is DNxHD, but many others use ProRes or Cineform with great success.

Again, if you are just doing some basic cuts, and maybe a correction of the white-balance, stick with what you're doing. But if you are doing more filters and so forth, you might want to examine changing your workflow to accomodate your more advcanced work.
 
So Perrone, for more filter intensive projects I still do XDCAM Transfer from the camera to make XDCAM files - then drop that into a Uncompressed, ProRes, DNxHD, CineformHD, etc. timeline?

Then after I edit in the higher quality tmeline, I export to what? XDCAM again? Or one of the higher rez codecs? What is your final file after everything is done?

Thanks.
 
Chadfish said:
About 10-15 min into the file I start getting a blockyness. It happens in a pulse like clear/blocky/clear/blocky/clear, switching every half second and lasting for a few minutes. This happens 2 or 3 times throughout the 80 minutes.
Click to expand...

This sounds exactly like what's happening to me.

Since I installed SL & FCS3, mpeg2 encoding is way faster, nearly twice as fast. But the quality is much worse than before. I used to do only 1-pass CBR and would put as much as 120 min on a single layer disc and the results were acceptable. Now that it's so much faster I do 2-pass VBR and almost always get blockiness like Chad described above. This happens even at maximum bit rates. I shoot almost exclusively HQ 1080/24P and I haven't yet tried to encode MGEG2 from another format.

I installed SL & FCS3 at the same time so I can't say which is the problem.

I will be watching Squeeze 6 very closely.
 
DrKing - I am still using Final Cut Studio 2 on OS 10.4.11.

I have been making 2.5 hour DVDs starting with SD NTSC footage for years. I just drop the full quality file into DVD studio pro, then lower the bit rate until it will fit onto a 4.5 gig DVD. No problems. This is the first time I have tried a long DVD with XDCAm footage. Maybe we need to find a DVD Studio Pro forum...
 
Chadfish said:
So Perrone, for more filter intensive projects I still do XDCAM Transfer from the camera to make XDCAM files - then drop that into a Uncompressed, ProRes, DNxHD, CineformHD, etc. timeline?

Then after I edit in the higher quality tmeline, I export to what? XDCAM again? Or one of the higher rez codecs? What is your final file after everything is done?

Thanks.
Click to expand...

My non-proxy workflow looks like this:

Camera (XDCam) > Batch convert to DNxHD
Timeline (DNxHD) > edit/color correct/grade/sync sound
Export > Jpeg2000 (master for archive
Export > h.264 for web-based use
Export > AVCHD for BluRay
Export > WMV for internal streaming server

The final spot for XDCam in my workflow is when I take the originals off the cards. After that, no more XDcam in the workflow. Lossy, long-GOP, 8-bit codecs just have no place for me.
 
PerroneFord said:
My non-proxy workflow looks like this:

Camera (XDCam) > Batch convert to DNxHD
Timeline (DNxHD) > edit/color correct/grade/sync sound
Export > Jpeg2000 (master for archive
Export > h.264 for web-based use
Export > AVCHD for BluRay
Export > WMV for internal streaming server

The final spot for XDCam in my workflow is when I take the originals off the cards. After that, no more XDcam in the workflow. Lossy, long-GOP, 8-bit codecs just have no place for me.
Click to expand...

I see. XDCAM never touches your hard drive. I'll have to do some testing on my next transfer. I've never even heard of Jpeg2000. 2 quick questions:

1. Are the files much larger?
2. Can you see much difference?
 
DrKing2010 said:
My guess is it's either a Compressor or Snow Leopard problem.

Funny how you started this thread to avoid hijacking another and this one quickly goes off on a tangent.

Graham
Click to expand...

I am NOT on Snow Leopard. I'm on 10.4.11.

And I don't mind the alternate tangent in this case. I had no idea I was ridin' dirty as far as workflow goes. Lesson learned.
 
Chadfish said:
I see. XDCAM never touches your hard drive. I'll have to do some testing on my next transfer. I've never even heard of Jpeg2000. 2 quick questions:

1. Are the files much larger?
2. Can you see much difference?
Click to expand...


Correct, well sorta. XDCam touches the hard drive, but only for the purposes of conversion to DnxHD. I will say that this is not ALWAYS true. I do use the XDCam stuff on the timeline if I am in a hurry (same day turnaround) and I am not going to do extensive grading.

1. File size is dependent on bitrate chosen. XDCamEX is 35Mbps. Avid's DNxHD proxy file size is 36Mbps. Typically this is what I use, so the file size is essentially the same as the native files. However, DNxHD has rates all the way out to 220Mbps (8 or 10 bit) much like ProRes. So if you are bringing in high quality sources (like RED, Viper, Uncompressed HD, Film scan, etc.) you have an option to preserve that quality all the way through your workflow. Jpeg2000 is variable bit rate, so you can adjust it to what you need. I find that it is slightly more efficient than Mpeg4, so I get essentially lossless results from XDCamEX with about 15-18 Mbps. This creates files less than half the size of the originals with similar quality.

2. Can I see a difference. It depends on what I am doing. If I am doing heavy color grading, I absolutely can see a difference. But in most cases, I am simply trying to maintain the highest quality I can, using a consistent workflow.

I invite you to run the tests like I did. See what you get out of it. I don't know that you can get a free Jpeg2k codec on the Mac, so you may want to do a trial. Or just try the DNxHD 36 and see how it works for you. It's not lossless, but it's visually lossless to my eye. At least with the XDCamEX source. If I were bringing in high-quality sources, I'd use a bitrate more suitable. And if I am doing heavy grading, I go to one of the 10-bit choices (90x, 110x, 175x, 220x).
 
I can't believe I've been suffering with lossy footage from the EX1 and never knowing why. I have over 250 video clips on iStock and Getty Images and all of them have suffered from the lossy process I've inadvertently using. Thank you for explaining the problems on here. I hope I finally am figuring out what my problem has been.
 
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