thewisteron

I have a video on my Axim that is about 20 minutes long. I used the guide that fibrizio wrote to format the video. It is perfect until about 10 minutes through. But then the sound and the video don't match up after that. Any ideas what the prob might be?

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....the Wisteron was the strongest of all Morrowindl's demons, of any Shadowen birthed in the lapse of the Elven magic's use....

schrags11

I get the same problem. Halfway through the video the audio and video get out of sync. No idea why.

geezer

Nicky's pages have a many tips and trick and he explains this A/V stuff so well, even an old geezer like myself can understand it.

Nicky's Guide to Fixing Audio Synch

His excellent site should be included in any "Must Read" audio/video help site list.

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Chemcat

Are you by any chance using stereo audio? I had the same problem when I was trying to use 40kbps/22Khz stereo audio along with 250 kbps video. The audio lag would get progressively worse. I imagine the Axim couldn't handle the higher bitrate. I redid it with 32kbps/22Khz mono audio along with the same video bitrate and all was ok. Furthermore it sounded fine also (at least to these old ears). I've got the PocketMVP settings set to "no AVI Index" and "enable cache" with the slider 3/4 to the right. I'm using a 400mhz Axim-ROM v. A03-cpu PXA250 400 MHz B2

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geezer

Straight from the PocketMVP help file:

AUDIO
There are a few tricks to be cognizant of when encoding the audio portion of your clip.

- Your PDA's ability to handle specific sampling rates. (ie older IPAQ's don't support 48 Khz sampling but rather 44.1 Khz or 22.05 Khz or 11 Khz)

- Converting between some sampling rates such as 48 to 44 Khz can cause synchronization problems. On the desktop one can and should leave the audio at 48 Khz if that is what it was originally, but on some PDA's you have no choice. Use Besweet or HeadAche to do this properly.

- Converting between video frame rates causes synchronization problems. (ie 29.97 to 24 fps)

- an mp3 cbr audio encode has fewer synchronization issues than vbr or nbr.

- Stereo ( joint or otherwise) takes twice the PDA processing power than mono.

- Your desktop needs either the MPEG3 codec or the LAME codec installed.

- joint stereo uses less bits that 2 channel stereo but uses about the same processing power on the PDA

- OGG compresses more than mp3, has better quality at lower bit rates (ie 64 kbps) but also uses more PDA processing power than mp3.

- synchronize your video and audio using software such as Multiquence which permits you to see the video and audio in separate tracks. You can zoom the video to see individual frames and thereby make precise alignments. You can shift the start of the audio to sync with the appropriate frame.

You can then use Goldwave to stretch the audio to make it match the video's length without changing the pitch of the audio. Or you can use the freeware programs that try to emulate this procedure without the visuals to guide you.

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thewisteron

Thanks for all the suggestions. I will try right now.

__________________
....the Wisteron was the strongest of all Morrowindl's demons, of any Shadowen birthed in the lapse of the Elven magic's use....