Mpeg2 720p plays fine on my render workstation but not on the other !??

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plainman007

Well-known member
I had rendered my latest project to an mpeg2 1280x720, 30mbps file for a presentation. The rendered file runs fine and smooth on my main workstation. But the file stutters and runs in slow mo with audio dragged out on the presentation system. Both systems are dual core and with 4 gb ram each. Seperate media HDD etc. Task manager reports CPU usage is just 10 to 20% when its struggling trying to play the file. So i dont think its a system bottleneck.

Is there a recommended and reliable codec pack that allows us to play the above mentioned file ?

Thanks
 
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If it's just a presentation and not for further editing, don't export in mpeg2 which requires proprietary codecs usually. Just export in h.264 or WMV as all it requires is either Quicktime or Windows Media Player.

Sure, I can suggest you download the latest ffdshow codec pack, but these are not exactly "super well tested" pieces of packages, and I am not sure it's wise to install on student's machines. Better go with Quicktime/WMP and the formats they support.
 
I will not be installing this on any students manchines etc. Its just my own system. I have a seperate system for the presentations. Unfortunately the software that plays back the video will only accept .avi or .mpeg. These are the only 2 options i have.

If i go the .avi route what is the best format of avi to opt for immaculate quality ?
 
Holy smokes! 30 Mbps? That's BluRay mastering rates.

Here's the primary problem. The .AVI container is not built to do this kind of work. Mpeg2 is, but it's proprietary thanks to the DVD Consortium. So both are less than ideal

If you want to stay mpeg2, drop the bitrate a LOT. Maybe by half. If you want to move to .avi then options are REAL slim. I did some playing around and the best option I found was On2's VP7 codec. It looks pretty good at 10Mbps and should play back ok.

You are trying to put a square peg in a round hole with this, so you're going to have to make some compromises. Sorry.
 
Hi Perrone,

Ive regularly rendered and run these bit rates. They run fine on my workstation. They also run fine and smooth on a $300 HDD based mediaplayer with Hi-Def support. That too from a measly IDE Drive. :). Before you suggest something,, the media player died out on me. So i need to play the video from a PC. And thats where i stand now.

Is 30Mbps really a very highbitrate ? DV and HDV is 25Mbps right ? Isnt this just slightly higher ? Please let me know if theres a difference here ?

Thanks...
 
plainman007 said:
Is 30Mbps really a very highbitrate ? DV and HDV is 25Mbps right ? Isnt this just slightly higher ? Please let me know if theres a difference here ?

Thanks...
Click to expand...

Yes, DV and HDV run at those rates. But consider that the MAXIMUM bit rate allowed on a DVD is 9.8 Mbps (and that includes audio), and 40 Mbps for BluRay and that is for Audio and video combined. The max on a AVCHD burned disk is only 20Mbps. And these are intended to be decompressed by dedicated hardware, not a PC with a software decoder.

Yes, DV is 25 Mbps, but the computer is only trying to play bask 720x480 frames which is a LOT easier on the display card. HDV with it's Mpeg2 compression at 25 Mbps is the closest comparison.

Take a look at this link:

http://forum.blu-ray.com/showthread.php?t=3338

You'll find that Hollywood movie releases on BluRay using Mpeg2 compression average around 20 Mbps. So when I see you trying to encode and smoothly play back 30 Mbps on a PC and not dedicated hardware, I have no trouble understanding why it might be problematic.

It's possible that your workstation that does it so well, has a graphics card with a hardware mpeg2 decoder or other enhancement, and the other one does not. I know trying to play back 30 Mbps Mpeg2 is dodgy on my very powerful laptop.
 
Hi,

I THINK 25mbps is the same irrespective of wether its dv or hdv. Its the total transfer irrespective of the framerate or frame size. If at the end its a 25mbps its jut that. Thats why the same hardware tape which is used for DV takes HDV too. Because irrespective of the pitch rate etc. Finally only 25mbps of data transfer is generated. And given the size of the 1440x1080 frame size then it shouldnt have been able to run from that HDV tape. The DV tape cannot output more than 25Mbps.

Guess what ? i dropped the 30 mbps and rendered to 20 mbps and that mpeg plays on my not so powerful laptop that has nothing but onboard intel graphics, 5400rpm drive, and just 512 mb ram. Im now zonked as to how my presentation system which is quite powerful doesnt play it back. But it has an Nvidia card which only accelerates Mpeg2 decoding and doesnt support pure HD.

I tried rendering to AVC HD and te aulity comes out looking like an average youtube sreaming video. Whats wrong ? Im unable to get HD quality renders using H.264 or AVC HD from Vegas.
 
Can you post a screen shot from your encoding settings page in Vegas? Let's see if anything stands out.

And as far as data rates you are correct. But take a DV file and play it full screen. The data rate hasn't changed, but the video requirement has. Data rate is not the only thing that is important when it comes to playing back video. I can compress my 1080p to 145 Mbps 720p and play it back just fine. But when I scale it to full screen, I can't get more than 16fps. It's the same file, and the same data rate. But system demand increases.
 
Yes i agree with you. When it becomes full screen the requirement on the graphics card increases. Was just talking about the data rate concept you mentioned earlier. But to be frank with you ive never ever faced a situation where ive had a file that could play minimized and not when its full screen.

I would like to bring to you attention a quaint thing i noticed on my humble latop. The 20mbps file i talked about. It actually drops a frame or two when playing minimized but tends to settle down and play smooth when increased to full screen. Just wanted you to know this since you mentioned the full screen notion.

That aside what sort of file do you render to that can take 145 Mbps ? Within Vegas ? Can you guide me to the render setting your using please ?

Thanks
 
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