What dictates Video Preview Quality?

Comments

musicvid10 wrote on 12/2/2014, 8:17 AM
MJPEG is not a bad intermediate format. Animation, medical and scientific equipment still uses it because of its color accuracy. The drawback is intraframe compression, which means high bitrates to maintain detail and motion.

I do lots of prerenders in HDV format to check timeline playback at full fps. Inters and proxies carry their own price tag in terms of prep time.
TeetimeNC wrote on 12/2/2014, 9:37 AM
>My final files are later all re-rendered anyway as uncompressed PNGs

Paul, I wasn't aware there is uncompressed PNG since PNG is always lossless at any compression rate. Do you do uncompressed for speed?

/jerry
Paul Fierlinger wrote on 12/2/2014, 10:00 AM
Jerry, sorry for being awkward with sentences. All I meant to say was "uncompressed (PNG) ...." in other words that my choice of an uncompressed format are PNG image sequences. I was rushing and being careless with that part because it talks about what happens beyond our subject at hand.

EDIT: @ musicvid: so when you say:
"The drawback is intraframe compression, which means high bitrates to maintain detail and motion."
should I take this as one of the reasons I was having so much trouble in Vegas with stuttering, jerky clips?
CJB wrote on 12/2/2014, 2:44 PM
@JohnMeyer I have SSDs for my OS and media drives.
videoITguy wrote on 12/2/2014, 2:57 PM
dancerchris, literally the only thing your SSD drives affect is the boot time of your OS.
Little to no effect on the codec handling we have been discussing thus far. A more specific situation like analog video capture, or multi-streaming uncompressed files is another story.
musicvid10 wrote on 12/2/2014, 5:52 PM
"should I take this as one of the reasons I was having so much trouble in Vegas with stuttering, jerky clips?"

Paradoxically, high intraframe bitrates and high interframe compression both have the same effect of burdening preview fps, though in different proportions.

Oh, and don't expect realtime performance if there are any effects on the timeline.

My out-of-pocket advice is follow johnmeyer's links and do HDV prerenders / proxies as necessary to see fluid motion.
Also explore other mjpeg decoders. The old ones are all going to use a single thread.

Paul Fierlinger wrote on 12/2/2014, 8:22 PM
At this point I am pretty well set, having a better graphics card and now knowing to turn down my quality values on the MJPEG interface. The combination of those two items plus on very rare clips using prerenders gives me solid playback performances.

By the way, I rendered one clip twice, using 80% and 100% quality settings and played them side by side, plus studied them paused closely and carefully on a large screen and saw absolutely no differences -- that's astounding to me. Thanks to all and particularly Kit for starting this thread.
musicvid10 wrote on 12/2/2014, 8:46 PM
If your talking about the quality slider in the video settings, that affects motion estimation and is rarely noticed in the output.
Kit wrote on 12/2/2014, 8:50 PM
This has been an interesting and useful thread for me. I usually use Vegas for making short animations. I create files in CorelDraw and then export them as png and bring them into Vegas.

Just now I have two pngs of a rabbit to simulate jumping. One track duration 1 second. There is track motion {3 key frames} on the track. Underneath is a second track Sony solid blue. No other effects, deinterlace set to interpolate. When I set it to loop and play it back it won't go for more than a couple of seconds without stuttering when set at best full. I'm using the default Vegas layout. Given my specs (first post) why does it struggle so much? Would I be better off with a different format than png but I want the transparency?. The size of the pngs is 3840 by 2160
musicvid10 wrote on 12/2/2014, 9:07 PM
"Just now I have two pngs of a rabbit to simulate jumping. One track duration 1 second. There is track motion {3 key frames} on the track. Underneath is a second track Sony solid blue. "

You are creating generated media on the timeline, not playing back source media. The video file, with the rabbit, with the track motion, and with the blue background, does not exist!

It is only a set of instructions.

All bets are off, because Vegas could not possibly render in real time without one helluva system.

Prerender. Why on earth is there so much aversion to such a simple workaround?

"Oh, and don't expect realtime performance if there are any effects on the timeline.

Best of luck.


videoITguy wrote on 12/2/2014, 9:30 PM
A perfect example of someone who has remained oblivious to the purpose of digital intermediates. Good Heavens now we understand the OP
Kit wrote on 12/2/2014, 10:44 PM
I find your remarks rather snide. How do I create a digital intermediate? I want to learn. I only do video editing once a year and my memory isn't as good as when I was younger. Please don't direct me to the help file as when I try to use it Vegas 13 crashes. Thanks.
Grazie wrote on 12/3/2014, 1:49 AM
How do I create a digital intermediate?
Simply put: Make a render of that section. Longer answer, this is ANOTHER render of the Project or section of your project that you can then further edit or bring back into VP to supplant your existing section that maybe be sluggish. It will NOT have any Composting, FX-ing controls because, basically, these have now been rendered-in to this newly rendered Digital Intermediary or newly rendered media file.

Here's the value, it is because your/my pc isn't having to struggle with all the maths that's going on in your raw project, all you/we are doing is taking the project to an easier manipulable state. All the heavy math-lifting has been now baked in. For this I use Lagarith, as my "go-to" DI renderer. It is fast and lossless. OK, it does produce large files, but if it is at the expense of getting the job done, well there yah goes.

As an aside DIs and PROXIES are created by other NLEs, as this is a way to get a better FPS. What VP does is not do this automatically, we have to do it manually - mostly.

I HTHs?

Grazie


musicvid10 wrote on 12/3/2014, 8:51 AM
Comment:
If one is making a digital intermediate for Handbrake, best not to use Lagarith, because it can be buggy with libav. UT is a nearly identical alternative.
johnmeyer wrote on 12/3/2014, 9:20 AM
I would also advise against Lagarith. It produces extremely large files, and because of the file size, disk performance can become a bottleneck when compositing multiple streams, or when doing multi-cam edits. Cineform is still the gold standard for digital intermediates, and for good reason: the company's entire reason for being was to produce the world's best digital intermediate format.

The free version, available at the GoPro site, may be good enough for what you are doing, although the pro version does offer higher quality settings.
videoITguy wrote on 12/3/2014, 10:02 AM
Goodness Grazie -Proxies have been a part of VegasPro NLE for years - various third-party plug-ins and scripts for a long time - most recently since Version 12 - has built in.

As for a DI being part of the NLE - I supposed you could say many of the codecs like Sony YUV or Sony MXF have been built-in with the idea of serving as a DI - although little guidance about the matter is shared by SCS. I suspect because each to his own in this sphere.
Grazie wrote on 12/3/2014, 10:24 AM
@musicvid10:If one is making a digital intermediate for Handbrake, best not to use Lagarith, because it can be buggy with libav. UT is a nearly identical alternative.Sorry, don't understand? Nothing knew to me there . . .

@JM: I would also advise against Lagarith. It produces extremely large files, and because of the file size, disk performance can become a bottleneck when compositing multiple streams, or when doing multi-cam edits.Yes, as I said, they are large. Didn't cover MultiCam, I suppose I should have. Thank you for adding that. Compositing? I hadn't really noticed?

@videoITguy:Goodness Grazie -Proxies have been a part of VegasPro NLE for years - various third-party plug-ins and scripts for a long time - most recently since Version 12 - has built in.Sure, I was meaning the way how other NLEs auto Proxies and put aside time to do it, where we have to get going with scripts and so on - yeah?

@videoITguy: As for a DI being part of the NLE - I supposed you could say many of the codecs like Sony YUV or Sony MXF have been built-in with the idea of serving as a DI - although little guidance about the matter is shared by SCS.That's closer to my very poor explanation. Thank you for highlighting my less than stellar explanation. Much obliged.

Grazie

Kit wrote on 12/3/2014, 7:13 PM
Thanks Grazie. I've started a separate thread about rendering.
Kit wrote on 12/3/2014, 7:17 PM
Thanks I'm still struggling to understand why a modern computer would choke on 1 second of video. Are you saying that the issue comes with using generated media? Would a png of a solid colour make a difference? I'm going to take a look at prerendering. Wasn't really aware of it before. When did that appear? Thanks again.
johnmeyer wrote on 12/3/2014, 7:46 PM
Thanks I'm still struggling to understand why a modern computer would choke on 1 second of video.Because it is not video.

As already pointed out, when you generate media -- like titles or keyframed still photos -- Vegas must create the video, frame-by-frame. Generating video is computationally intensive. If you look at high-end examples, where animators start with wireframes, and then add texture, and movement, and shading and ... it takes hundreds of computers crunching 24/7 for months on end in order to render 90 minutes of video/film.
musicvid10 wrote on 12/3/2014, 7:50 PM
If it's not already a video file, meaning 100% original, NO changes, then it has to be rendered in real time, because no video resulting exists! That's all there is to it, really.

Prerender.

Prerender.

Prerender.

Prerender.

videoITguy wrote on 12/3/2014, 9:31 PM
Kit, animation creation and finish work maybe a far different animal from what most video editors deal with. I suggest you think a bit about what sphere you are attempting to work in. You might be trying to use an NLE to create animation and that can be done. But the concerns you are raising point to a whopping need to understand the how and what of animation.
Paul Fierlinger wrote on 12/4/2014, 4:09 AM
Kit, if you want to discuss this with me over the phone, I'd be happy to talk with you. If you decide to do this, contact me privately through this forum and I'll send you my phone #. I live in the Philadelphia area (or we can Skype, which would be even better)

Paul