deadheadfred

I have been using the excelent how 2 guide on converting movies to play on the ax.

One problem, the audio is always out of sync. Starts out great and then gets worse and worse.

Any body have some settings to use on virtual dub to correct this error?

TIA

Talyn

This thread:

http://www.aximsite.com/boards/showt...threadid=11672

deadheadfred

Have read the thread several times, but can't seem to get it write. Do you have any boiler plate settings?

Talyn

Lame MP3 codec, any bitrate, stereo. Assuming you're doing landscape video? So far doing portrait view I can use the Frauhofer MP3 codec in mono with no problems (same settings all the guides say to use).

deadheadfred

I ahve downloaded lame several times, but never got the inf file mentioned in the thread
http://www.aximsite.com/boards/show...&threadid=11672

Where did you get yours?

Talyn

From the Lame website.

If memory serves (and I'm not sure that it does) the codec is archived in a .zip file, and the .inf is included there. Just unzip the contents, right-click the .inf and select Install.

deadheadfred

I did mange to find the file. Still absolutely no luck in portrait or landscape, lame or mp3.

does it make a differnce in the source? avi or mpg?

Talyn

No, your source file makes no difference whatsoever; only the final version that PocketMVP plays.

Which Axim do you have? Mine is the Advanced (ie. 400Mhz) and I only have audio sync issues on landscape video, which is why I switch to Lame stereo to keep them in sync. My portrait videos, I can keep in mono with the Fraunhofer codec, and so far they stay in sync just fine.

deadheadfred

I have the 400. What video bit rate do you use in landscape?

BTW the voice lags behind the video.

Talyn

That's the exact opposite problem that the others and I experienced - we had the audio playing approximately 1 second before it should have.

What bitrate are you encoding your DivX at? To my personal standards, 160Kbps is the lowest bitrate I will use, and even then it depends on what I'm encoding. Traditional cel animation (ie. cartoons) look fine at that bitrate, but for anything else, it can be slighty fuzzy depending on what's happening in the video. 224Kbps seems to give very good quality and acceptable filesize for both portrait and landscape video.

The 'sweet spot' for DivX and PocketMVP seems to be in the 200-300Kbps range, depending on your CPU/RAM and video content.

The whole reason we went with Lame stereo (any bitrate) with landscape was to cause the audio stream to use more resources, therefore keeping in sync with the video stream (landscape takes more resources than portrait). Assuming (yes, I know what they say about 'assuming' :) ) that logic can apply in reverse to your situation, perhaps your video is encoded at too low a bitrate, so it is easier to play than the audio, which is why the audio lags? (Just an off-the-top of my head theory of sorts)

deadheadfred

Here is another option. Could the origianl avi encoding be a little off, not enpugh for the pc to fix on the fly. When i rencode it for the ax, it just compounds the issue?

mmw

I had the same audio sync problems where it started out 1 sec behind and got farther out of sync towards the end.

I have since fixed the problem. I believe the problem has to do with the 48kHz to 44.1kHz (or multiple of) audio conversion. Most PC sound cards can handle both 48kHz and 44.1kHz audio streams. My bet is that the Axim can only handle the 44.1kHz (or mutiples like 22.05, 11.025) audio streams properly.

This would explain why the PC plays the AVI without the sync problem.

When I performed the initial encoding of DVD VOBs using XMPEG, I would always have audio sync problems. However, when I used FlasKMPEG to initially convert the VOBs I have no audio sync problems (I used the DVD to AVI guide listed in these forums).

This leads me to believe that the problem may be with the audio produced by XMPEG or the audio frequency conversion performed in VirtualDub.

Hope this helps.

Talyn

deadheadfred: yes, it is entirely conceivable the source video was slightly out-of-sync to begin with, though simply watching it very carefully would give you a clue about this.

mmw: correct, the Pocket PC platform does not handle 48KHz audio, hence the instruction in the guides to convert the audio. 44.1KHz is fine, though a bit overkill for a PDA.