rendering to mp4 - losing sync

LarsHD wrote on 6/8/2009, 4:02 AM

Hi,

VP9 in WIndows XP 32 bit:

Dropping a 640x360 uncompressed AVI on the timeline. Project is 3 min long and 29.97 / 44.1 kHz audio. This is my "copy master" that I have rendered out from a 1920x1080 project. It plays fine in Vegas and audio/video is in sync.

I go into RENDER. I chose the following settings to render an mp4-file:

VIDEO
Frame size: 640x360
Profile: Baseline
Frame rate: 29.970000
Pixel aspect ratio: 1.0000
Number of reference frames: 1
Use deblocking: unchecked
Constant bit rate: 2 000 000

AUDIO
Sample rate: 48 000 ( I also try with 44.1)
Bit rate: 128 000

PROJECT
Video rendering quality: Best

-----------------------

P R O B L E M
===========
I render and then look at the file in the little QuickTime player. The sound and video is now *not* in sync. Audio is around 0.5 second ahead of video I'm not sure if it drifts and get worse the longer in the program I get.

----------------------------------------------------------

I'm obviosuly doing somthing wrong here but cannot figure out what... Please help...

best & thanks in advance
Lars

Comments

John_Cline wrote on 6/8/2009, 4:14 AM

Are you using the Sony AVC encoder? What you may be doing wrong is using the Quick Time player.

LarsHD wrote on 6/8/2009, 4:23 AM

I'm about to send a file to an advertaising agency and they are all on Mac. So I though mp4 was the way to go... (?).

Yes, Sony AVC is what makes the mp4 in vegas sin't it? Should I use something else?

If I render an MOV it also get out of sync, although a little less.

I was looking at my file with Apple QT player as I assume that is what they will be using.

If I render to WMV it is perfectrly in sync.

What do I do wrong?

Best,
Lars

John_Cline wrote on 6/8/2009, 4:27 AM

Seriously, I think the problem may be the QT player itself, I've always had stupid little problems with it. Apple really doesn't know how to write PC software. It may play perfectly well on their Macs. Have you tried another MP4 player, like VLC?

http://www.videohelp.com/tools/VLC_media_player

LarsHD wrote on 6/8/2009, 4:46 AM

Main Concept, mp4 - out of sync too

LarsHD wrote on 6/8/2009, 4:46 AM

Ill try the VLC, hang on...

LarsHD wrote on 6/8/2009, 4:53 AM

Thanks a lot John. Obvisouly the Apple QT player fails to oplay MOV and mp4 correctly in the WIndows environment here...

VLC plays these files in perfect sync.

However, the colors are really wrong and the VLC isn't picking up the calibration profile on my monitor (like WIndows, Photoshop, Vegas etc do). 'm not sure if this is an isue but it would be nice if VLC played the colors just like the other players here.

Best & thanks so much for helping me John
Lars

John_Cline wrote on 6/8/2009, 5:13 AM

Glad I could help, Lars.

In VLC, under "Tools" > "Preferences" > "Video" there should be a setting called "Output" where you can choose from many methods for VLC to write to the video card, one of those settings will probably pick up your color profile. I'm not currently on a machine with VLC or I would find the correct setting for you.

LarsHD wrote on 6/8/2009, 5:30 AM

Right again John! I checked "Windows GDI video output" and the colors got right where they shold be!

While we're at it...

I see that at some settings, rendering to MOV, MP4 and WMV the codec sets itself to the 16-235 range and in other settings (whithout telling me) it accepts and produces a file with the full 0-255 input that I'm feeding to the mp4/MOV/WMV.

SCENARIO A: a certain setting produce a WMV file that contains 0-255

SCENARIO B: whithout me knowing why, anoitehr setting is producing a file that isn't allowing enything below 16 or above 135 through to the final WMV.

(0-255 and 16-235 is another topic so we should not get into that now... ;)

What I need to have control over is *why* and "when* the 0-255 material gets its 0-16 and 135-255 cutoff at some settings when rendering to these formats.

Any ideas here?

Best
Lars

farss wrote on 6/8/2009, 6:14 AM

Which "setting" is making the changes occur?

Bob.

LarsHD wrote on 6/8/2009, 6:50 AM

Well, sort of difficult to say. Have't experimented enough. But what I see now is that the same WMV file shows the entire 0-255 in the VLC player while WMP only shows 16-235. Settings in WMP? Or leave them and just be aware of how it reacts? I don't want to make files that other view differently.

So it seems that I need to learn a bit about what players show 0-255 and which ones play 16-235. And why?

What's your take on this Bob? ALso seen this problem / issue?

best
Lars

farss wrote on 6/8/2009, 7:08 AM

"Settings in WMP?"

maybe not directly.
There's more than one way to write video to the monitor. I think one is overlay mode and that's affected by settings in the video card.

I do recall when I was tweaking these settings I did notice they affected some players and not others.

Normally PC displays and WMV expect luma = 0 to 255.
Be aware though different computers, displays and projectors can vary widely on this.

Bob.