Audio/video sync issues with HD MXF files?

smhontz wrote on 3/12/2012, 10:32 PM

I'm working with 1920x1080 24p 50MBps .MXF source from a Canon XF 305 camera, using Vegas 11. I want to render my project out to an intermediate file. Ultimately I will be rendering to WMV for upload to YouTube, but I like have the intermediate file so I can watch all the effects, composites, etc in real-time.

In the past, when working with regular ol' NTSC DV 720x480 footage, I would just render to AVI, look at that, and do my final render to either WMV (for YouTube) or MPG for DVD.

I tried rendering my project to Sony MXF, using both the "HD EX 1920x1080-24p" and the "HD422 1920x1080-24p 50 Mbps" templates. I then bring the resultant MXF file into Vegas to watch it. This seems to work, but at times, it seems to me like the audio and video are out-of-sync slightly. Not sure if that's really there or not. The preview window shows it is playing back at the full frame rate of 23.976.

I tried rendering to AVI, but the files were huge - a 1.6GB MXF file ballooned up to 24 GB, and wouldn't play back well at all.

Are there really sync issues with MXF files used as an intermediate like this, due to the compression of the already-compressed MXF source files? Does anyone else see this kind of thing?

I'm pretty new to using HD footage so I'm not quite sure what to expect.

Comments

xberk wrote on 3/13/2012, 4:41 PM

>> it seems to me like the audio and video are out-of-sync slightly. Not sure if that's really there or not.

Check the sync on your MXF proxy files on the timeline. Right click the particular event (audio or video) for pulldown menu, then "synchronize" ..

Does everything appear to be in sync if you render the MXF proxy files to another format, like MP4 or MPG ?

I use MXF proxy files with no issues for sync ..