DivX to .SWF conversion always converting without a sync.

May 22, 2006 9:53 PM

DivX to .SWF conversion always converting without a sync. I have a video that is an .AVI (DVcodec), I converted it to DivX via VirtualDub and later on converted it from DivX to .SWF via (Flash Video Studio 1). For some unknown reason, whenever it gets converted to .SWF, the audio/video are not in sync.

The main reason why I did this is because more people can see flash videos rather than DivX (at least my friends group.) I am looking for the correct way to convert this so it does not keep coming out of sync.

I've tried converting the raw file (the avi/dvcodec) one and it converts it to flash just fine, however, the file size is rather large, I am also looking for a way to compress it a little bit.

If it helps, the original avi file (DvCodec) is 270MB. When I convert it to DivX via VirtualDub, the size is knocked down to about 26 with almost no quality loss. So the third step is where I get shafted, which is the conversion to SWF which normally works, but never when I do it via DivX to .swf. Is there an alternative way? Should I convert the original file via VirtualDub to some other codec and then try to do in Flash Video Studio? Or is there another way I should do this entire procedure?

Any help is greatly welcomed. Thank you in advance!

posted by cheero to computers & internet (7 comments total)

Ooops. I apologize for the entire question being on front!
posted by cheero at 9:53 PM on May 22, 2006

For the most part, I myself only see sync problems in transcoding when the audio in the original has been encoded using a variable bitrate mp3 encoding. That may or may not help you.
posted by Ethereal Bligh at 10:25 PM on May 22, 2006

Indeed -- try changing out your audio codec in VirtualDub. Go PCM if you can -- it's, what, 600MB an hour? Not too bad.
posted by effugas at 10:56 PM on May 22, 2006

What video framerate does your conversion tool think your video is using?

If the answer is "30 fps" then that's your problem. It turns out that it isn't 30, exactly, for NTSC. Rather, it's 29.97 fps, and if you tell it "30" then the video/audio synchronization will drift by 0.6 seconds every 10 minutes cumulatively.
posted by Steven C. Den Beste at 11:05 PM on May 22, 2006

With the original file
When you go through flash studio:

Lower the frame rate in 1/2
Lower the data rate to around 140KBytes/sec (or around 1000kbits)
Lower the picture size to 320x240
posted by filmgeek at 3:29 AM on May 23, 2006

Why not .flv with a .swf container? That is pretty much the standard these days (youtube, google video, etc.).
posted by i_am_a_Jedi at 4:40 AM on May 23, 2006

[moved more to inside]
posted by jessamyn at 5:28 AM on May 23, 2006