Audio cut out

rickraz wrote on 3/23/2009, 10:07 PM
Hello, I am new to video recording and video editing. I recently purchased the Sony HDR SR11 HDD HD camera. I am recording a sermon and the camera breaks up the sermon into 2 files (1 is 2 gig and 1 is 1.5 gig). When I look at the 2 files the video doesn't seam to break up but the audio is a brief pause. Of course this happens mid sentence and it's very weird (and noticeable). Also as an FYI I am using a line in for the audio. The audio doesn't break up anywhere else during the recording.
This is last weeks video on vimeo
http://www.vimeo.com/3733096
Move to 12:59 and you'll see what I mean. I would think that this is not an issue with Sony Vegas but I hope it's not a problem with my camera. Do you know if I can change a setting in my camera to keep larger files?

Thanks for your help!
Rick

Comments

rickraz wrote on 3/29/2009, 11:32 AM
Any Ideas on how I can create a larger file?
newhope wrote on 3/30/2009, 4:51 AM
This may be related to the maximum file size on a FAT32 formatted medium, hard drive or flash memory. Hence the camera is segmenting the files into a maximum of 2GB.

I've just checked some larger files from my Panasonic HDC-HS9 and I have a 2.47GB file from the hard disk. So it obviously isn't limited to 2GB maximum file sizes, not sure if the Sony has that limitation... they are similar consumer AVCHD cameras.

Although not an ideal option have you considered dropping the record format down to a slightly lower setting. For instance...

* HD FH 16Mbps (1920x1080):430 mins
* HD HQ 9Mbps (1440 x 1080):880 mins
* HD SP 7Mbps (1440 x 1080):1070 mins
* HD LP 5Mbps (1440 x 1080):1370 mins
* SP HQ 9Mbps (720 x 576):880 mins
* SP SP 6Mbps (720 x 576):1310 mins
* SP LP 3Mbps (720 x 576):2510 mins


Choosing HD HQ instead of HD FH would double the duration you can record in a single 2GB file while still offering a good quality HD video format. You may trade off a little quality but solve your file size/break dilemma.

New Hope Media
rickraz wrote on 4/1/2009, 12:56 PM
newhope, thanks for the info. I was under the same fat32 assumption as you. I would think that even a consumer camera designed to record in gHD would use a file system that allowed for a larger file size. I did as you suggested (drop the quality) and I didn't have a +2gig file so I didn't get any of the choppy audio. Thanks for your thoughts!

Rick
newhope wrote on 4/2/2009, 5:17 AM
The file size limit should be 4GB not 2GB, well on Panasonic AVCHD cameras a least.
So I don't understand why the Sony is splitting files at the 2GB barrier.

I note that Panasonic indicate that files split because they are above 4GB might have some lost frames of audio when imported into Premiere Pro CS4.01 and Edius.

No mention of this for Final Cut Pro.

Vegas doesn't get any mention a all.

pwppch wrote on 4/2/2009, 9:36 AM
So I don't understand why the Sony is splitting files at the 2GB barrier.

4GB is a FAT32 limit.

2GB is a Wave PCM format limitation. You can write out a wave file upto 4GB, but there is no assurance that it will be read correctly.

This is a limitation of the WAVE header structures.

It is also why we invented Wave64.

What is Wave64?

I don't know what the specific issues are with the captured data, but it sounds like something is doing its math wrong when spliting up the files.

Peter
newhope wrote on 4/2/2009, 8:34 PM
2GB is a Wave PCM format limitation

Peter,

Thanks for your input.

Reading the original post though it appears that the Sony camera is splitting the AVCHD files on the camera at a 2GB barrier. It's not a wave file limit as the AVCHD would have a Dolby Digital (.ac3) audio track I would have thought, certainly that is the normal situation with the Panasonic and, I thought, the standard for audio in AVCHD.

So do you have any ideas about why the Sony camera would be splitting the files at the 2GB mark?
It's certainly got me stumped.

New Hope Media
pwppch wrote on 4/2/2009, 10:42 PM
I don't know what format the camera is producing. Do you know that it is not producing a riff format but an actualy AC3 encoded file?

So do you have any ideas about why the Sony camera would be splitting the files at the 2GB mark?

No idea.

The original poster should submit a bug ticket against this or contact Sony Electronics regarding the file format issue.

Peter


newhope wrote on 4/3/2009, 5:56 AM
The audio the camera records is encapsulated in the m2ts (AVCHD) file.

Normally audio in m2ts is ac3, either as stereo or in the case of some consumer cameras 5.1 surround.

This particular camera, the Sony HDRSR1,1 is capable of recording Dolby Digital (ac3) 5.1 surround format.

Regardless it isn't an uncompressed WAV file which would be the only reason that the 2GB limit for WAV files would possibly be reached.

The file size limit for AVCHD is 4GB not 2GB and the maximum data rate for the camera is HD FH 16Mbps (1920x1080)= 430Min on the 60GB hard drive.

At this rate 4GB would record approximately 30 minutes of video and sound at around 7.17 minutes per GB.

My guess is that the camera was actually set to HD HQ 9Mbps (1440 x 1080): 880 mins per 60GB.
This would have recorded around 58 minutes 40 seconds or thereabouts for a 4GB file. which I would suggest may have been the real file size.

Rick could you confirm if the file break was at 2GB or 4GB?

I agree that a closer inspection of the operation manual of the camera and possibly contact with Sony Electronics would be the best option if the file split did happen at 2GB though.

New Hope Media