Recompression

[Bobby]

When I create my Assembly project pulling all the chapters together in PRE, I have been outputting AVI files from the chapter projects. DVDA says in its documentation that MPEG files will not have to be recompressed; should I switch to MPEG output from the chapters to use in a DVDA assembly?

What do you guys use?

[Bill Hunt]

Remember that I use PP & Encore, so things might be different.

I Export as DV-AVI elemental streams, Import into Encore and let it handle the Transcode settings to "automatically" fit the material (all Assets) onto DVD. Encore can also be set various Transcoding settings manually, as well. See below.

The other route is to calculate the bit-rate for each Asset, based on:
1.) the total Duration of each
2.) the images contained in each, i.e. camera, or subject motion
3.) the capacity of the DVD, i.e. DVD-5, or DVD-9
4.) the max bit-rate per the DVD specs. Note: though below the max combined bit-rate, for greatest playability, something in the 7KB/s to < 8 seems to be the best for the Video. Remember, the spec sets the COMBINED (Audio & Video) to 10.8 KB/s, IIRC. This is the MAX, so no "spikes" can ever exceed that MAX.
With this method one basically works backward from the capacity of the DVD used, and ALL Assets must be considered, Menus, Motion in Menus, all Video and all Audio. This allows for Assets with low motion to be Transcoded at a lower bit-rate, while Assets with higher motion are Transcoded with higher bit-rates. A bit-rate calculator and lots of practice are required. Using this method, one is *usually* best to still use elemental streams, with MPEG-2 for Video and either PCM/WAV 16/48, or AC3, for Audio. I almost always produce DD 5.1 SS, so AC3 is the way that I go.

Unless DVDA strips out the MPEG Audio and re-Transcodes it to PCM/WAV, or AC3, this must be done, if you are muxing and creating a delivery stream, as MPEG Audio is NOT allowed in NTSC DVD specs. and is only "optional" with PAL. So, if you go the bit-rate calculation and MPEG Encoding route, you must have either PCM/WAV, or AC3 Audio, and must calculate that too. PCM/WAV takes up more room.

Unfortunately, you may have to do some "between the lines" reading to adapt to DVDA, as I do not know that program, how it works, and how it handles Assets.

Let us know what you find out, as DVDA seems to be quite good and popular. Since Encore is no longer available as a stand-alone, my workflow is pretty much a dead-end, unless one purchases PP with Encore bundled in.

Good luck,

Hunt

[Steve Grisetti]

Output as a MPEG2s, Bob. You'll get excellent, smart-rendered results from DVD Architect.

You can't really assemble your chapters in DVD Architect Studio, so there's no point in outputting from Premiere Elements in parts. (Well, you can assemble video clips, but it becomes something called a compilation, and it's probably not the most efficient way to do it.)

Just output your entire project as an MPEG. It's easy to add and label scene/chapter markers in DVD Architect and then, if you'd like generate both a Play Movie button and a Scene Selection sub-menu.

If you've got additional clips you want to add to your DVD as outtakes, bonus footage, etc., those should be separate video clips. You just load them into the DVD's structure one at a time.

[Bill Hunt]

Steve,

Pursuant to my answer to Bobby, tell me a bit on how DVDA handles muxed MPEG files. If one JUST Exports as a muxed MPEG, the Audio will be MPEG too, unless one specifies PCM/WAV or AC3, right? Since MPEG Audio is not within the DVD-spec. for Audio, are there any special instructions there?

Thanks,

Hunt

[Steve Grisetti]

DVD Architect Studio lets you choose between three audio outputs: PCM, AC3 and 5.1 AC3.

If the footage you're providing has its audio in one of those formats, it too will be "smart rendered" and not re-compressed.

Does that answer your question, Hunt?

[Bill Hunt]

Yes it does. Thanks. Also, it's nice to know that it handles DD 5.1 SS AC3. Does it allow 5.1 monitoring (with proper hardware), or is it pass-through, like Encore, where it's recorded properly to DVD, but can only be monitored in stereo?

I don't want to hijack Bobby's thread, so I'll keep my questions to a minimum,

Hunt

[Steve Grisetti]

Sorry, Hunt. I'm not sure of the answer.

[Bobby]

Thanks Steve - you answered my two main questions. To reiterate:

I shouldn't use DVDA as a replacement for my assembly process; I should still do that in PRE and that does solve some issues such as transitions between chapters if each chapter is a separate sub-project. Then use DVDA to create the menus; I will have to manually set the scene/chapter points but I was doing that manually in my PRE assembly anyhow - just made a bit easier because I could easily tab to the start of a new scene on the timeline. I can also stop using PGCEdit to add the pre-menu clip.

Second, to use MPEG2 output.

Sounds good - I will report back in a few days as the next project continues - I still have a few chapters yet to do.

Thanks

[Bobby]

Status: Doing pretty good. I finished my project and exported it as MPEG. That actually went pretty quickly, and DVDA seemed very happy with it, and generated a DVD image fairly quickly also.

I was able to stagger through setting my own chapter markers and finally figuring out how to create a Scene menu and link to it. The .pdf that comes with the program was useless for that, but I "figgered" it out.

My only issue right now is that the video exported to MPEG was definitely lower contrast than what I saw in PRE. I did a test export to AVI just to check, and the AVI looks just fine. Playing the MPEG via Nero or within DVDA and it was definitely more washed out.

Any ideas on how to work on that?

[RJ Johnston]

My only issue right now is that the video exported to MPEG was definitely lower contrast than what I saw in PRE. I did a test export to AVI just to check, and the AVI looks just fine. Playing the MPEG via Nero or within DVDA and it was definitely more washed out.

Any ideas on how to work on that?

I don't think you should do anything. The final product should come out correctly, especially if smart-rendering is used.

When you export to MPEG-2 for DVD in Premiere Elements, the 0 to 255 values of the RGB colorspace are mapped to 16-235 in another colorspace per some video engineering standard with the numbers 601 in the title. It seems that those 16-235 luma values are not converted back to 0 to 255 in DVDAS, and that is probably the same for DVDA. That would make the colors looked washed out when played back within DVDA. But that should only look that way within DVDA. Since the MPEG-2 is smart rendered, the final product will be correct.

That's my theory. What I'm wondering is if there isn't smart-rendering, will the colors come out correctly? Is the colorspace conversion problem only happening for playback of previews within DVDA, maybe for the sake of speed??

[Bobby]

Thanks RJ. Yes, I am aware of the"601" issue with black level, but never encountered it before myself.

But this is not a DVDAS (I think we should add the trailing S for Studio) problem. When I look at the MPEG output just with a viewer it is washed out. The output of DVDAS looks the same as the input. An AVI generated from the same PRE project looks OK.

So this might be a PRE issue. I used the DVD Widescreen preset and I noticed that in it was a Quality slider that went to 5 but defaulted to 3 - what does the Quality slider do in this case? I kept the default of 3.

[Paul LS]

I think that is what Robert is saying Bobby, it is the export from PE to MPEG that changes the color space. And then of course with the smart-rendering in Sony it is maintained.

[Bobby]

Sorry Paul - I didn't get the full impact of what Robert said. I am working on the DVD output of DVDAS now, and will see what it looks like to verify his contention that with smart rendering it should come out like it should.

[RJ Johnston]

For your convenience, I downloaded DVD Architect 5.0a and saw the same thing.

I used the bars and tone clip in Premiere Elements for testing purposes. From pre7 I exported the bars and tone clip to MPEG-2. Then I added the MPEG-2 to DVDAS and DVDA. When previewing the clip, pure black is measured as 16,16,16 and pure white is 235,235,235.Those numbers were created when exporting from Premiere Elements to MPEG-2.

After you create a DVD from DVDA, when you play the DVD back on your computer, the pure whites correctly measure 255,255,255 and pure black measures 0,0,0. I used Fraps to take a snapshot of the DVD overlay screen in order to get a JPEG that I could measure the values. Normally when you run a colorpicker over a DVD overlay, you only get a black value no matter what color your picker is over.

Even if smart rendering isn't used, the final DVD comes out correctly.

[Bobby]

Great Robert - thank you for the work - I really appreciate it. I wish I had some of your tools

I will generate the DVD and see what it looks like to verify - was out all day taking my wife for an extended Sunday drive and lunch so I didn't a chance to work on the problem.