Showreel compression grief

cardigan

Hi guys

I'm just trying to put a showreel together (in HD 720p at 30fps) and am having some trouble with compressing the final video - no matter what I do I seem to get the odd stutter on playback. I have tried compressing using xvid and divx at different quality settings, resolutions etc and played the video in Windows Media Player, Media Player Classic and VLC but I can't get playback 100% smooth. The stutters happen in different places on each playback so it isn't a problem with the source video.

Other videos on my PC don't seem to have this problem, so I must be doing something wrong.

Sorry if this seems like a weird question to ask here, but I figured other artists might have had the same problem working with high res, high quality video - most of the stuff I've found by googling relates to web video or ripping to DVD etc.

Rob Galanakis

What program are you using to compress? Video compression is one of the most needlessly complex things I've ever worked with, there is so much that can go wrong- give as much info as possible, please.

Also check the source video itself to make sure it doesn't have a stutter.

cardigan

OK, well I don't think the source video has a stutter because the I can play the same compressed video file back several times in a row and the stutter will happen in different places each time.

Its a bit hard to check the lossless-compressed source video for stutters because the bitrate is so huge my PC can't play it back realtime anyway.

I'm using Sony Vegas Pro 6 to edit and then compress the final video to an avi file. I've tried 1280x720 and 640x360 resolution, xvid, divx, wmv3, even cinepak exhibits the same problem (aside from the other problem of it looking like absolute balls!)

The file has no audio by the way, and audio is turned off in the export options. I've turned interleaving on and off with no difference, field order is set to none (progressive scan), framerate is 30 (source video is 60) 'Create an OpenDML compatible file (Avi 2.0)' is ticked.

The stutter is quite minor really but you notice it because the vid is all smooth camera sweeps, so I'd really like to get rid of it!

Thanks for your help!

kodde

First off I would consider not using Xvid or DivX... What if that recruiter does not have any of these codecs? You think that he/she will go download and install it, or have a look at the next applicant in that huge pile?

If you ask me the safest possible way to go would be WMV. The later versions of WMV aint all that bad. Pretty much any computer running Windows XP or later can run this without installing any extra mumbo jumbo. If you do not wanna go for WMV then I'd suggest QT since in my opinion this would be the second most common format available. At least among formats that are useful at all.

Regarding your stutter issue. You say that playback of the source video file has the stutter issue, but at different locations each time you play it? Well why is that? Because of the very high raw bitrate? Did you try playback with a different media player? Did you try playback on a different machine? Did you try encoding with any other software? I'd recommend Media Player Classic or VLC (Video LAN) for playback.

When I work with video editing like this I usually use Adobe Premiere for the editing part, then either SUPER for WMV or QT, or VirtualDUB for AVI. I almost never compress the video in the actual editing program. The community freeware programs usually do a better job, even if there is an abundance of homebrew apps out there.

Good luck.

gamedev

Just a few additional thoughts:

You don't need to be running at 30fps - this is waste. You can get by with smooth video at 24-25 fps. Additionally, I've had a lot of luck encoding w/ Quicktime using the H.264 codec using AAC for audio. This can be done w/ Quicktime Pro or software like Camtasia. With the settings below, you can achieve 720p at about 10mb / minute. It's a great quality vs size tradeoff.

Video Bitrate: 3000 kbps
Audio Bitrate: 96 kbps

In addition, as mentioned, format and codec is really important if you want potential employers to view it w/ no problem. I'd highly recommend using something like Vimeo's HD video service. You could upload a high quality .mov to them and then offer HD streaming flash video on your site (and not worry about hosting fees) since 98% of the population has flash installed.

Good luck.

-Tyler

cardigan

Thanks for the advice guys - I was thinking the exact same thing about using xvid and divx being a bad idea - I downloaded microsofts wmv encoder but couldn't get the WVC1 high quality codec to work. I'm going to try that SUPER program out and see if I get better results, I'd never heard of it before so thanks for the heads up!

kodde

SUPER
It's actually a quite competent freeware encoder capable of most common formats and codecs, including WMV and MOV. There's an abundance of AVI-tools out there, WMV- and QT-tools are not as common in my experience.

cardigan

Well, I gave SUPER a go and it easily encoded to wmv (WVC1) and mov (H264) which is great, but the stutter is still there and in the .mov file it is much worse than in either avi or wmv! Arghh!! I was using a bitrate of 3120 with no sound.

I'm going to try playing it back on my wifes laptop to see if it works there but her laptop is so rubbish it will probably stutter really badly on that anyway!

Any other ideas?

Psyk0

What's the CPU usage when you playback your file?

Troubleshooting an example file would make it easier...

gamedev

Yea, it sounds like if you're still having playback issues at a bitrate of 3100 something else is going on.

Conversely, have you tried just uploading your video to a service like Vimeo (which offers a 720p version) and letting them do the video conversion / hosting?

Can you post a file?

cardigan

Try dowloading this.

On mine if I play it back repeatedly it will always stutter at least once in different places each playback. Hopefully its just my stupid computer and it'll work fine on everyone elses (crosses fingers)

My CPU usage is about 15% by the way, so I don't think that's the problem.

StJoris

Doesn't stutter for me when I play it, but there is some quite annoying flickering motion blur I think is going on, is that what you mean?

cardigan

Hey, well at least it doesn't stutter!

I think the 'motion blur' is vegas interpolating the frames (from 60 down to 30fps) and it is a little ugly now I come to look at it.

Trouble is, I'm playblasting out of the Maya viewport - this isn't a render its all realtime cgfx shaders, so there is no proper motion blur to smooth it out a bit - if I convert the file without putting it through vegas so there is no interpolation it actually looks a bit worse.

I could use hardware rendering to render out from maya with some motion blur but... jesus this showreel has taken me way too long already.... also when I tested this at the beginning I didn't get much of a quality improvement, so I figured playblasting with hardware AA was the way to go.

kodde

Well, can't say I'm experiencing any stuttering. But that flickering is horrible, making my eyes bleed.

Psyk0

15% load is good, no problem there. Keep in mind if you have an older video card, chances are you will have problems playing HD video.

I couldn't play the file at first, i dont use media player, only vlc or the "classic" media player with ffdshow. It appears WVC1 codec isnt part of ffdshow...or i need to update.

Anyway, after installing the codec, i have no problems playing back the file, there is some buffering happening at the beginning (lags for 3 seconds), which happens with some wmv files.

One thing that seems a bit wrong is the "keyframes", im not sure how wmv deals with this, but in an .avi file if you dont set up enough keyframes the playback will stutter.

Web video tends to have infrequent key frames, like one every 10 seconds, because compression efficiency is paramount. In contrast, HD tends to have a lot more key frames. This is because playback performance is as much of a challenge in HD as compression efficiency. A key frame every two to four seconds is a good starting point for an HD WMV file.

I dont know your codec/encoding setup, but if i had to render a demo reel, i'd load the images in virtual dub, pick ffdshow ---> divx or mp4. .mov would be a good idea too for compatibility and of course online streaming.

[Deleted User]

Does your video have lots of heavy/fast action or cuts?
Off the top of my head -its been a while since I had to encode any video- check your key frame settings. Try playing around with that and you might get smoother playback... maybe
Hope you get there one way or another.:)

McGreed

What about the use of FLV files? Is FLV format only good for small animation (lower resolution) or can it be used for larger as well?

cardigan

Thanks for all the replies and help guys, I think I've pretty much got it sorted now. Turns out vegas had a wmv export all along which does the trick very nicely. Don't know how I missed it, duh! Had to sort out that motion blur problem by just slowing the camera motion down a bit so its less noticeable, its still a teensy bit ugly but liveable with. Stutter seems to be my PC rather than the vid.

Anyways thanks again!