Using Compressor with HDV looks blocky...revisited

Here's a weird problem I have experienced since I've been using Compressor:

When I output a project to MPEG2 using Compressor, it looks a little "blocky" on my 32 inch HDTV monitor when played on a standard DVD player...ESPECIALLY with graphics and text.

The way I have been making DVDs for the past several years has been to lay my edited project back to HDV tape, and then play that out of my Sony Z1U downconverting to standard def. and recording on a Panasonic DVD recorder, stripping the MPEG2 and the AC3 off the disc using MPEG Streamclip and make my authored disc with menus in DVDSP.

I posted this probably a year ago and never got any resolution, but recently I made an interesting discovery which I hope can help solve this issue.

I ran a test.

TEST 1: HDV footage captured as HDV, edited, and exported to self-contained QuickTime in HDV, opened into Compressor using DVD Best Encode 90 min. setting. RESULTS: blocky looking.

TEST 2: HDV footage captured as HDV, edited, and exported to self-contained QuickTime in DV anamorphic, opened into Compressor using DVD Best Encode 90 min. setting. RESULTS: blocky looking.

TEST 3: HDV footage captured as DV anamorphic, edited, and exported to self-contained QuickTime in DV anamorphic, opened into Compressor using DVD Best Encode 90 min. setting. RESULTS: BEAUTIFUL FOOTAGE!

So the problem went away when I captured HDV as DV anamorphic.

Any thoughts as to why this is happening, and how to actually encode HDV in Compressor in a way that works, would be appreciated!

Thanks!
Casey Petersen
www.unitedvideoinc.com

There are a few places where your workflow is kinda ? well, ugly.

Let's go with the first thing you said: shoot HDV, cut HDV, lay back to HDV tape, downconvert in the deck to a DVD recorder, then back into DVD Studio Pro.

By my count, that's an absolute minimum of four massive compression hits, and maybe five.

These days, most acquisition formats are heavily compressed. So while it's a disadvantage to shoot in HDV, it's not the end of the world or anything. The problem is that you're taking that already compressed footage and compressing it again, repeatedly, as it moves through your pipeline.

Now, if you originate in HDV and deliver on DVD, then there's no way to avoid brutally compressing your footage twice: once when you shoot it, and once when you master your DVD. Those are unavoidable. But the key is to get your footage out of the heavily compressed acquisition format and into an intermediate format that's either uncompressed or perceptually transparent, then keep it in that format until you're ready to master.

Your original workflow starts on HDV (compression hit #1), then gets written to HDV again (compression hit #2), then gets converted to DV in your deck (compression hit #3), then gets converted to MPEG-2 in real time by the DVD recorder (compression hit #4). There may be at least one digital-to-analog-to-digital conversion in there as well, depending on how you connect your deck to the DVD recorder.

A better workflow would be to shoot HDV, edit uncompressed or ProRes (which is perceptually transparent), then use Compressor to do a single, multi-pass conversion to MPEG-2.

The reason you get better results when you downconvert to DV out of the camera is because DV is, while still heavily compressed, less heavily compressed than HDV. DV takes 270 Mbps SD video and squeezes it down to 25 Mbps, while HDV takes 1.5 Gbps HD video and squeezes it down to the same 25 Mbps. By compressing it less, and fewer times, you get better results.

But you're still stomping all over your footage, unnecessarily. DV is really incredibly crappy looking compared to uncompressed SD, and there's just no need to drop down to that format. It's better than your original, screw-up-my-footage-as-much-as-possible-please workflow, but it's still screwing up your footage.

Now, you don't say whether you're dealing with 60i or 24p material; you also didn't say anything about your edit system. The ideal workflow will vary depending on which format you're shooting, what kind of edit system you're using and so on. So I'm not going to try to map out a step-by-step ideal workflow pipeline for you here. But in general, when dealing with compressed source material and a compressed delivery format, make sure you're not compressing your footage anywhere else along the way. It's not necessary, and, as you've seen, it visibly degrades your footage.

Thanks Jeff,

First of all, the footage is 1080i60.

Second of all, my edit system is a Mac Pro - quad core with 10Gb RAM.

We had a discussion maybe a year ago about whether or not I should be capturing as ProRes and editing ProRes all down the line. My objection then was a time issue. For me, doing ProRes took longer to work with because rendering was slower, and for many projects I do, there is not much time in the budget for editing, so I have to do whatever is fastest...even if it's not the best quality, but it's acceptable quality, all things considered.

You've given me a lot to think about...maybe there's a way I can make this ProRes work by changing my workflow habits, because yes I do want to keep up the quality the best I possibly can, and don't want to be limited by budget or time. Maybe I need to try another project in ProRes and experiment with ways to make it work faster.

But still, I wonder why I haven't heard this HDV/Compressor issue from anyone else on this board. It's obviously blocky to me.

Thanks!
Casey

Something definitely isn't right. Rendering HDV to ProRes is much faster than rendering and conforming HDV on modern systems.

What kind of framestore do you have? Can you just work in uncompressed 8-bit?

Here's another sticky point from our previous talks that I can't remember, regarding settings:

Capture - HDV or ProRes
Timeline - HDV or ProRes
Render codec - same as sequence of ProRes

Framestore? What do you mean...where do I look?

The framestore is the storage device where you store your media files.

I use a few external FW800 hard drives, a 300Gb, a 250Gb and a 1Tb.

YIKES. Okay, you definitely can't work uncompressed, then.

Maybe that's why ProRes is slow for me.

What do you have?