Lost my keyframes when converting divx to vcd

[hazmat42]

Chances are that nobody is ever going to read this and that I will have to live with it, but I'll post my problem anyway. I have a divx movie that is divided into two parts, and when I play both halves of the movie in WMP 7, I can fast forward through the file fine. However, when I converted the movie to MPEG-1 using TMPEGenc V. 2, the audio and video were fine, but I can only fast forward through the first few minutes of the movie. The rest of the keyframes that were there in the divx file are now gone! I can burn the VCD to disc and play it find, but I cannot fast forward beyond the first few minutes of the movie. I already tried to join both halves and re-drive the keyframes in Vdub, but when I encoded the newly spliced, redriven divx into VCD, the audio was OK but the picture would freeze periodically while the audio would keep playing. As the VCD continued to play, it would get more and more out of sync. Is there any program out there (preferrable freeware ;&gt ) that could redrive VCD keyframes? Or does anyone out there have any suggestions on how to solve this problem?

<font size=-1>[ This Message was edited by: hazmat42 on 2001-11-20 07:47:13 ]</font>

<font size=-1>[ This Message was edited by: hazmat42 on 2001-11-20 07:48:38 ]</font>

[Shabubu]

Ummmm, first thing, mpeg1 files (VCD) don't actually have keyframes in them (well they kind of do, but not in the same way as your normal avi file). If you can open up your file in virtualdub and get the option to re-derive keyframes then your file isn't MPEG1 (the only option that pops up will be load I frames/P frames/B frames and accept partial MPeg streams).

Can you be more specific with how you made your MPEG

[hazmat42]

Oops, I guess I didn't articulate my problem properly. What I meant to say was that I first encoded my two divx files into VCD and discovered the problem while playing back the new VCD files. I figured that there might be a problem with the keyframes in the source divx files, so I decided to redrive the keyframe flags of the divx so that I could reencode (little did I know that the redrive would take over two hours!). Maybe the index of the divx files is corrupt, but I don't know how to correct it in VDub. VDub's help section isn't really specific on the topic and only says to save the file using direct stream copy for both the audio and the video. Originally, I encoded the source divx files in TMPEGenc V.2 into MPEG-1 using Sefy's Video-CD-NTSCfilm template (which is over 23 fps). What do I need to do to the source divx files so that when I encode, I will to play the VCD and fast forward through the movie. Since the redrive had disasterous results, I'm at a loss as to what to do next. Hopefully, someone out there had had the exact same problem and has a magic bullet which will solve everything (without having to create a new MPEG-1 files).

BTW, What do you mean by "mpeg1 files (VCD) don't actually have keyframes in them(...not the same...as...normal avi files)? I've made a few VCD's, but I'm still a little wet behind the ears. I don't completely understand how a VCD file works, so what is the VCD's equivalent for keyframes? Maybe you could give me a few pointers.

P.S. Thanks for responding. I couldn't find any other question like this in the forum. I honestly thought this question would just sit in some forgotten corner of the conversion section.

<font size=-1>[ This Message was edited by: hazmat42 on 2001-11-20 21:59:47 ]</font>

[Shabubu]

https://www.videohelp.com/phpBB/viewtopic.php?topic=66612&forum=10

Explains it much more eloquently than I can I frames are the keyframe equivelant, P frames are the rest and as far as I'm aware there are no B frames in AVI's.

As for fixing your divX, the only way I could suggest was the rederive, then setting both audio and visual to direct stream copy and saving. That should fix the headers. If that doesn't work then....

The problem may not be your MPEG though, it might be the player, or the way you burned. Try making a VCD with VCDEasy (from the tools section), and try on a different player.

[hazmat42]

Actually, I got the same fast forward problems when I played just the MPEG-1 file in WMP 7, so burning isn't the problem. Thanks for the link, I'll check it out!

<font size=-1>[ This Message was edited by: hazmat42 on 2001-11-20 22:48:30 ]</font>

[hazmat42]

OK, based on what I read in the other post, I can deduce that when fast forwarding or rewinding an MPEG-1 file, the player searches for the I frames in the GOP structure of the file. Therefore there must be headers somewhere in the GOP structure of the VCD pointing to the I frames so that you can track the movie. Am I making any sense? Is there a way to repair my VCD files without reencoding by modifying the GOP structure?