Stop Conversions From Changing Sound Timing

[KT888]

Does anyone know how to stop conversions from changing sound timing so the sound and video are out of sync?
This happens on occasion and I have no idea why.
I'm looking at one right now it just happened to. It started as an flv file and I converted it to an avi file using Videopad.
My OS is W7 Ultimate x64. The Videopad version is 3.58
I also use WinAVI a lot v11 and it happens sometimes with it as well. I haven't noticed if it's a specific file type it happens to I'll have to keep track but it's very annoying.

Thanks for your help.

[hech54]

FLV files are bad news....always have been. You are better off converting them to something completely uncompressed, making sure that all is still in sync, THEN converting them to your final file.

[LigH.de]

There are three main reasons for asynchronity.

1) Delayed audio stream in the source: It was added on purpose to bring the audio in sync to the video in the source. During a conversion, this delay has to be detected correctly and copied or compensated in the result. Depending on the source format, this is not always easily possible; e.g. for DVD Video sources, it requires a tool which knows how to analyze IFO files and handle Program Chains.

2) Variable framerate: Realtime encoders often cannot keep a constant framerate, or very similar frame content is combined to one frame to save bitrate. Not every converter han handle this attribute easily, many try to enforce a constant framerate, losing sync to the audio stream.

3) Decoder lag: It is small, it is constant, and some playback systems know how to compensate it on their own. Others don't know. A different audio codec may help; or compensating it explicitly.

[KT888]

FLV files are bad news....always have been. You are better off converting them to something completely uncompressed, making sure that all is still in sync, THEN converting them to your final file.

That sounds like a good suggestion. Can you tell me some Uncompressed Video Formats. I used Google to look for some but unbelievably couldn't find any.

I've seen this happen with mkv and mp4 as well. I'll try your suggestion on these files as well.
Once I find an uncompressed format I can use.
I Didn't even know there were any left these days other than raw I mean and I don't know how I could use that starting with a file that has already been encoded.

[redwudz]

Three lossless or near lossless codecs:

Grass Valley HQX Codec

HuffYUV

Lagarith Lossless Video Codec

These and others are available in our Tools/Software page to the left.

[LigH.de]

Also recommendable: The Ut Video Codec Suite