Questions about some AVI problems and Divfix v1.10

[wwervd316]

Hello I have some Xvid AVI's that have some video and audio issues. The video has some bad frames and goes pixelated for a second or two as a result the audio goes out of sync when this happenes but only when converted to dvd with nero. To fix the audio problem I began using convertxtodvd now the AVI's stay in sync but in order to do so the dvd will pause, the screen will go blue for a second and then black for another and then skips one second from where the video left off and continues. This all takes place quickly but in some videos this happenes over 15 times. That many times is rare but makes that episode hard to watch. The pixelated frames are still present in the video but dont make the audio go out of sync like before. After the pixelated issue appears on the dvd it almost always is soon followed by the blue and black screen frezee. Sometimes the video will skip in the middle of a scene to the last few minutes of the AVI. To fix the dvd I have to skip over the jump in the video and rewind back to the point just after it skips appears when I do this the video will play fine but as you can imagine it does ruin everything when your sitting their trying to get the video back to the right spot and seeing scenes that haven't come up yet. Sorry for any misunderstandings in my explaination but sometimes it is hard to tell you what I see.

Divfix v1.10 I downloaded this program and checked my AVI files for errors but it doesn't find any problem im sure this is because the problems happens after I convert the AVI to dvd. I use the nero 7 player sometimes because it fines the points in the video where it goes pixelated. Whenever I watch the files on the computer I use windows media player 10 and there is never any problems with the file. I also wanted to know what rebuild inex and strip index will do in divfix. Thanks for your time and any help you can give in advance

[guns1inger]

Basically, you are downloading crap. It was either crap to begin with - poorly encoded, poorly zipped etc, or it was corrupted during one of th emany download/upload cycles between when it was first encoded, and when you got it. Whatever the reason, data inside the file has become corrupt. Depending on what is corrupt, and how badly, you may be able to salvage it, you may not.

Do not confuse playback quality with encoding quality. Playback is a different kettle of fish, where error correction and compensation may allow a video to play with minimal disruption. Encoding, on the otherhand, requires a clean source. It doesn't compensate for damage in the same way, so problems like this show up as more severe than you may have previously believed them to be.

I have yet to see any repair tool that can fix all problems, or even many problems, well. If it is as simple as a corrupted index then even just doing a Direct Stream Copy through virtualdub will probably fix the problem.

Video compressed with something like Divx or Xvid can suffer small problems very badly. You might have up to 300 frames between key frames. If a key frame gets damaged, the subsequent frames will also be affected.

I would suggest trying to use avisynth to load the video files. Use virtualdub to verify the results by watching through the corrupted parts to see if you get a clean read. If so, use a standalone encoder to encode the results. If not, delete the file and stop downloading poor quality material.

[redwudz]

I would say about the same thing as guns1inger, but Avisynth can be a little intimidating for beginners.

You might want to start out with VirtualDub Mod. Start up VDM and click 'File>Open Video File'. Then click 'Ask for extended options after this dialog' near the bottom of the screen. Select your video. When the options page opens, select 'Re-derive Keyframe Flags'.

Your video should load. Go to 'Video>Scan video stream for errors>Scan'.

Play your video through in VDM. If you have corrupted frames, you can cut them out with VDM.
Go to 'Tools>VirtualDub' for guides on how to do this.

You can also apply filters, crop, trim, edit, change the audio to a different format and a few hundred other things. VirtualDub and VDM have a lot of options.

Finally, select the same codec as the video and save it under a new filename. You may need to install the Xvid codec if that is your format. This may, with variations, fix your video, or at least make it play better. A lot of work, but if you want a crappy video cleaned up, not a lot of options.

That's the short/short version. To get the details you will have to read the VD guides and do some studying and experimenting. Good luck.

[guns1inger]

I don't suggest avisynth lightly, because it isn't straight forward first time out, although programs like fitcd can ease the entry somewhat. But I have found it can sometimes handle suspect files better than other, easier to use programmes. If VDUB works, great. If not, avisynth is the next step.

[redwudz]

I've got to 'bite the bullet' and learn Avisynth myself. But it is a little intimidating for beginners.
But from what I've seen, it's well worth it.

[guns1inger]

Straying somewhat off-topic, start with AVSEdit. It is a simple development environment for avisynth scripts and has a condensed version of the avisynth help files included. Very handy and easy to work in.

This post is also worth a read, https://forum.videohelp.com/viewtopic.php?t=297929 as are many more in the restoration forum. Eventually you will wonder how you did without it.