HD - Performance Penalty

[Bobby]

I guess I crossed a milestone of sorts today.

Since I don't have a Blu-Ray writer yet, all of my work has been SD DVDs and some upload in QuickTime format to Vimeo.

I moved to a Canon HV30 around last June, but haven't ever really done an HD project. Most of my work is creating DVDs from old VHS and Hi8 tapes, and there was no need for HD. Anything I grabbed off an HV30 tape (small projects) was downconverted in the camcorder.

But, of course, the video on the HV30 tape is HD and I finally decided to start doing all my projects in HD and downconverting to Vimeo or DVD for output. Today I stared my first project - video of basketball games for my two grandchildren. Things I noticed:

1) I captured the clips using HDVSplit and of course got a number of clips - in this case about 25 m2t's. When I brought them into PRE7 it took noticeably longer than SD clips. Not only did it conform the audio, but it also said it was "indexing" the clips and that took quite a while. Thumbnails were not available for any clip until the indexing was finished.

2) Opening the existing project was also significantly slower than an SD project.

3) I ended up with about 9 minutes of video and the editing process went fine, with no performance problems or issues. I had just put together a high speed video editing machine last summer and this surely helped.

34 But worst of all was generating the .mov file. I used my settings for Vimeo HD (1280x720) and it is going to take at least a half an hour to render the video. Downconverting was taking far longer than similar length SD projects I have done. And the process was very I/O bound - CPU utilization was only about 33%; all 4 processors were cranking. This seemed to be much more I/O bound than an SD project.

Anyhow, further analysis later.

The goal here was to only capture once, and in HD, for all projects. But I am starting to think that may not be worth it, performance wise.

[George Tyndall]

But I am starting to think that may not be worth it, performance wise.

Hi Bobby,

I've been creating SD DVDs from HD m2t Timelines ever since my testing showed that I could produce a SD DVD from that Timeline that would be AT LEAST as good as I could get from downconerting in camera.

I can't comment on the relative time to index and conform the clips as I have minimal experience working with SD, but I can tell you this: Assuming our hardware is similar, PRE7 will Share a 9-minute un-rendered HD m2t Timeline to a SD Folder VERY quickly--and the SD DVD that you will get from burning that folder, if your experience is similar to mine, will be of unmatched quality.

In fact, the process of burning to folder then burning from folder is so fast that, nowadays, when I think I'm done editing and I'm ready to watch a smooth playback of my work, I burn a SD DVD then play it back. I do not any longer spend an extended period of time rendering the Timeline for playback.*

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*Despite the fact that m2t is native format and does not need rendering, my experience is that, when I've finished adding my titles and transitions plus any editing of the m2t clips that may be required, it takes far more time for PRE7 to render only those changes than it does to burn a SD DVD from the entire Timeline as I've described.

[Bobby]

I haven't tried burning a DVD image to a folder - will do that next. Thanks George!

Edit: Interesting. I created a SD DVD image from the same project and it only took a couple of minutes. So it is taking about TEN times the processing time to render a .mov file as it is to create a DVD image. And the resultant .vob file in the image was over four times LARGER than the .mov file.

Now the .mov was 1280x720, but I also tried a 864x480 (my usual SD widescreen dimensions for the files I produce for Vimeo) and there was little difference.

Hmmm - I have to think about this.

[George Tyndall]

Hmmm - I have to think about this.

Here are some additional data for you to ponder while you have your thinking cap on:

I just finished an 11-minute "music video" that consists of 64 HD slides, each with a transition, plus a minute or so of animated titling on HD Motion BGs at the beginnnig, followed by another animated title and HD Motion BG at the end.

If I would choose to render this Timeline, PRE7 infoms me that it will take 80 minutes to complete. So I skipped rendering and instead Shared to a SD DVD folder. Here is the data:

Time to create the folder/image: 6 minutes and 9 seconds
Time to burn the DVD from the image: 2 minutes 25 seconds
Total Time to Produce the DVD: 8 minutes 34 seconds, or about 1/10th the time to render it--and in this latter case the project still would not be "in the can" (outputted in final form).

And that is why, when I'm ready to check for smooth playback, no matter what form of output the client desires, it's now my standard procedure to burn a SD DVD via a folder.

Additional data:

All the photos are 2288x1520.

The slide show was created in PSE7 then "sent" to PRE7, where the HD Motion BGs and animated titles were already on the Timeline waiting for it.

The Project Preset was: NTSC-Hard Disk...HD 1080i 30 and "Default Scale to Frame Size" was checked. (I compose my photos in my camera viewfinder just the way I want them to look in the slide show--and i do make frequent use of the zoom lens--so I only rarely do any panning or zooming with either PSE or PRE.)

[Chuck Engels]

If I would choose to render this Timeline, PRE7 infoms me that it will take 80 minutes to complete.

Never trust the estimated time in Premiere Elements. It would probably only take 3 - 4 minutes is all, just let it render and see.

[George Tyndall]

... just let it render and see.

Thanks for pointing that out, Chuck.

Here's a summary of my data:

As stated earlier, time to produce a SD DVD including first burning to folder: 8 minutes 34 seconds

Time to burn directly a Blu-ray (BD-R) DVD, no intermediate disk image: 23 minutes 27 seconds*

Time to render the Timeline: 22 minutes 36 seconds

Conclusion: With this particular HD project, hardware and software, I can burn a Blu-ray DVD--and nearly 3 SD DVDs--in about the same amount of time as it takes to render the Timeline.

Chuck, I suspect that your particular hardware is what makes the difference. Do you agree?
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*Time to create an image of the Blu-ray DVD, using the CyberLink software that came with my LG Blu-ray burner: 2 minutes 53 seconds

Time to burn that Blu-ray disk image to a Blu-ray DVD: 3 minutes 55 seconds

[Bobby]

This morning, I put together a simple test project - HDV. I put exactly 4 minutes of clip on the timeline, and there was no timeline rendering needed (i.e. no red). I then output to various formats.

Creating a .MOV file 1280x720 (what Vimeo likes) took 13 minutes.

Taking the same project but outputting to my VImeo SD preset (864x480) took 10 minutes and interestingly created a file almost identical in size. I went back and played these two, and the higher definition file was in fact at higher definition.

Creating a SD widescreen DVD of this project took 5 minutes.

Creating an AVI of this project took 3 minutes, although obviously there was less compression going on and the file size created was much, much larger - as would be expected.

I then created a new SD widescreen project, put 4 minutes of video on it, and it created a DVD in 3 minutes and the .MOV file in 4 minutes..

Then I forced the project to need rendering by putting in Fade In where necessary. The timeline went all red. Rendering took only 3 minutes!

So what do we glean from all of this? If we look at generating a .MOV file, then the HD penalty is about four times - 4 minutes for a normal SD project and 13 minutes for an HD project. Of course you get higher quality output, but that is the question here - what is the PENALTY for HD.

But there are some anomalies. Rendering was fairly short, as was DVD creation and AVI generation, but the .MOV took a much longer time. Why? Generating an AVI file (SD resolution) and then creating a new SD project and generating the .MOV was faster than generating the SD .MOV from the HD project - 10 minutes vs. 3+5 minutes.

I tried Exporting an .mpeg file and then creating a new HD project and importing the .mpeg. No real change in .mov generation time, but the audio in the project was breaking up badly - the video looked OK. The audio data seemed to appear in the audio timeline track OK, but the playback had long silent gaps. Not sure what was happening here. When I played the .mpeg file with WMP, there was severe horizontal smearing, although the audio seemed OK!

I wish I had a Blu-Ray writer to continue the test. So what is my bottom line here? I think HD just isn't ready for prime time, at least with PRE. The idea is capturing everything as HD and downconverting in PRE when needed looks like the wrong workflow for me.

EDUT: I restarted PRE and re-ran the project that used the .mpeg file as input and the audio was OK, so I think that may have been perhaps a Windows resource issue that went away.

[Chuck Engels]

Chuck, I suspect that your particular hardware is what makes the difference. Do you agree?

I don't know if it would be much different on my machine, but it didn't take 80 minutes like the estimated time said, that was my point.

I wonder if it would be faster burning the disc now that it is rendered?

[Bobby]

The estimates do in fact seem to be incorrect, but get better as you go on. This would be true on any estimating program routine. My timings were all real elapsed time, not using the estimates. In fact, the estimates started out about an hour for the one that ended up as 13 minutes, but fairly quickly converged below 20.

[George Tyndall]

I wonder if it would be faster burning the disc now that it is rendered?

I re-edited the movie to make it shorter before I saw your post then rendered it to see how the actual time compared to the estimated time, so I can't tell you (I no longer have an un-rendered version), but I am starting a new HD project now, and I'll compare the time to burn a rendered versus an un-rendered version then post the results in a new post.

Thanks for making me aware that the estimated time to render is meaningless.

[Paul LS]

George, you can delete your render files... go to Timeline>Delete Render Files. You can then render again.

[George Tyndall]

George, you can delete your render files... go to Timeline>Delete Render Files. You can then render again.

Oh?

Thanks for that, Paul.

But I think I will do the research that I promised Chuck when I get to a shorter project later this afternoon.

But while I have you on the phone, so to speak, does the following idea seem accurate?

There is no point in rendering 2288x1520 stills to the native format of my Project Preset (1920x1080) IF my goal is to create a SD DVD because, once rendered, the Timeline still needs to be re-endered to the proper format for the SD DVD (VOB?), so I might just as well go directly from the un-rendered state to the rendering to SD DVD format.

In other words, I might as well go directly from A to C rather than A to B to C.

[RJ Johnston]

There is no reason to render a preview other than to see how your edits look, and sometimes you don't even need to do that for edits. The files that are rendered for a preview are not used for anything else. You might as well export the final product and see what it really looks like instead of rendering the entire timeline first.

There are exceptions. For example when you are in a standard project and then export to MS DV-AVI. The rendered preview files will be used for "smart rendering" as long as you clear that checkbox for Recompress on the Video tab..

[George Tyndall]

There is no reason to render a preview other than to see how your edits look, and sometimes you don't even need to do that for edits.

Thanks for the confirmation.

I was going to ask you what "smart rendering" is but I don't do SD, so I won't bother you with that question.

[George Tyndall]

So what is my bottom line here? I think HD just isn't ready for prime time, at least with PRE. The idea is capturing everything as HD and downconverting in PRE when needed looks like the wrong workflow for me.

Given the quality that one can get from "up-rezzing" a SD DVD with a Blu-ray player and an HDTV, it is difficult to justify the higher cost of HD media and the additional time it takes to create HD projects.

But on the other hand, if one has a series of well-composed, well-lighted and well-posed photos or clips that one wishes to display for maximum effect, there is no question that, especially on a larger HDTV, a Blu-ray project done properly with PRE7 (HD Templates, top-quality audio, etc) blows SD out of the water.