Sync during random access

[lakedude]

Is it possible to keep sound and video in sync during a fast forward or random access with DivX? My DivX movies play fine as long as you start from the beginning but sound leads video after a fast forward. I seem to remember reading that starting from the beginning is required due to the progressive nature of DivX, is this true? Have tried a few players and one (Micro DVD?) offers a “bookmark” option which I haven’t had a chance to try yet but is supposed to allow going to any “bookmarked” spot. If true random access is not possible then maybe a bookmark every five minutes or so would work. Does anyone know if bookmarks can be added automatically? TIA

Currently using DivX Fast and 14 KBPS MP3.

<P ID="edit"><FONT SIZE=-1><EM>Edited by Lakedude on 11/30/00 10:32 PM.</EM></FONT></P>

 

[Guest]

In any video when sound does not sync, you can alter the frame rate of the video so that it matches again. Use Virtual Dub for this. On the videos I have edited I can most always get the sync down to a fraction of a second which is noticable only if you listen really hard. Virtual dub has an auto adjust which sometimes works, but you can also manually adjust it if that fails.

 

[lakedude]

Goomphy

Thank you for your response. Unless I am missing something VD will not help because my movies are not out of sync. They play perfectly if started from the beginning and are allowed to run their full length without interruption. The sound and video sync perfectly from beginning to end. The Problem comes in when you try to skip ahead or rewind. This may not be fixable but it would certainly be a nice feature to have working. Am I missing something? Thanks again.

 

[Guest]

That's a strange one. Never encountered it myself when fast forwarding or rewinding. Try VD anyways, just give it a shot and see if you can tweak it out where it would work. In effect, resynchronize it. I'm not totally sure, but that might redo it where it would work. Might be worth a try. Other than that, I honestly wouldn't know where to go with it. Good luck.

 

[lakedude]

Are you saying you CAN fast forward and rewind? How far apart are your keyframes? Doom9 is saying one every second but he is shooting for one DVD on two CDs and I am trying to fit one DVD on one CD.

Are you using “Direct Stream Copy” or “Decode Audio” ? I have been using one key every 10 sec and Decode Audio.

Thanks again for your help.

 

[Guest]

I have variated my key frames and used both audio modes and have had no problem with sync after running problematic videos through VD. First thing I do is to check by seeking to the near end of the video for sync. If I don't have it I play with VD until I get it right. Manually adjusting the frame rate and narrowing down the correct rate is sometimes the only way I can get it to work right. I suppose the reason I may not have ever had your problem is because I always check sync first then correct it if need be. I usually use decode audio and a key every 10 sec but I don't think that effects sync. One thing I do is to NOT compress the audio to MP3. I initially write out the file with uncompressed audio and then after I get sync correct, I convert it with VD to MP3. Shaves the file down to a reasonable level for use on one CD. Doom9 is right about one thing. It looks better on 2 CD's, but who wants to change mid movie when you find the quality acceptable? Some people demand more quality than others.

 

[lakedude]

Thanks again for your help.

Since using VD have had no problems with sync in mp3 or divx sound sync. Could not find the mp3 codecs at first but hitting the “show all” box made them come up. Mp3 sound is taking about and hour to re-interlace but divx takes only about 10 minutes. Not all rates work in either format but I found working ones that I’m happy with. Quick question to Goomphy: When you say you make the original sound uncompressed exactly what setting are you using? I am not finding “uncompressed” or “direct stream copy” for sound in Flask.

Being able to FF and RW is sure nice!

BTW p4 hauls in Flask. Almost does real time conversion. Liked friends so much got one coming Monday.

 

[Guest]

For uncompressed output in flask I use no codec. I allow the program to write out the divx file containing wav audio. I compress afterwards. Wish I could find more good mp3 codecs for using in VD afterwards. The ones that I have don't support VBR encoding.