Conversion Tool from DivX3/4 to MPEG4 ISO, working on both Windows and Linux

I posted a bug regarding CBR muxing in VirtualDubMod and in contact with the fixing developer(Stream9) I made the suggestion to include code to identify VBR MP3 files so they are not CBR-muxed without any comment (as VdubMod is doing it at the moment). He said this would be a good idea and I should post it as a feature request in CVS RFE, so perhaps someone is really going to implement this and you can use it in your tool... Otherwise this tool is a good idea...

I can't say with certainty but I believe the only potential obstacle to a MSMPEG4v2/MSMPEG4v3/WMV1 -> MPEG4 convertor is the storage of the DC component for intra blocks (MS may be more precise than MPEG4 allows - 9 bits versus 8). Everything else I found has a suitable lossless replacement in the MPEG4 spec, and everything that's needed is in ffmpeg already. I had plans to work on "something" over this month, perhaps I should finally do this convertor instead. You knew this would happen to things I work on didn't you Nic :) -h

mate, pls. gimme a shout if i should make contact once you know how to do it. Oh I'll do it for free, I meant to do it a while ago as it's just a cut-n-paste job with ffmpeg's existing codebase. Thus it will be LGPL'ed regardless. -h

Re: Conversion Tool from DivX3/4 to MPEG4 ISO, both based on Windows and Linux - paid 

Well I just made a list of everything that needs to be changed to allow lossless conversion. There's no way I can decouple the necessary parts from ffmpeg any time soon, so it'll just be a command-line tool that accepts a DivX avi file and outputs an MPEG-4 one with CBR MP3 audio. Here's the result of 2 hours of searching and yawning over ffmpeg. I'll see whether implementing these changes is as simple as it sounds tomorrow :) Code:

-h, Looking at the code, I think there is another potential problem: iDCT accuracy. The MS encoder uses a fast but not accurate iDCT. Playback using a MPEG-4 decoder's compliant iDCT will cause drift artifacts to accumulate. Perhaps it's possible to correct these while doing the conversion, but it would be quite a headache. Or hopefully they are not too bad.

Say, -h, you might be able to get that laptop you wanted for your train rides now. :) ...and what container format is the neuston player going to use?

As -h was pointing out he doesnt want any payment but plans to release the code as GPL or even LGPL ( i would NOT recommend LGPL for various reasons, but accept his decision here of course ) i will make the following recommendation to Neuston Corp. : LGPL'ed code can be relicensed to GPL, and I will license the modifications I make as GPL anyway which will automatically remove LGPL'ed freedoms from redistribution. Though I would like to see the code added to ffmpeg itself some day, which requires LGPL. - a decent 'consultation' payment for -h , to be paid on a monthly basis, in return -h will work on the project as administrator until every existing DivX3 AVI can be converted into a OGM or whatever file that plays in perfect sync on the Neuston player Ouch. Sounds nice, but debugging hundreds of AVI sync and mismatch issues? :( I'll see what I want to commit to once I have an idea as to how problematic the conversion will be. - a more than decent one time donation to this place, to FFMPEG project and maybe to corecodec.org ( BlackSuns and Betaboys upcoming open source community, specific for audio and video compression ), where the project should be hosted ( i will beg -h not to use sourceforge ;) ) My initial thought was to pop a zip file onto geocities :) Certainly a donation should be made to ffmpeg if the tool works, and if they still have money left to give away I wouldn't object to them doing so. -h

I checked out the features of the two mentioned players and one point struck me as being rather important: GMC and QPel are not supported. This has been an issue for both the XCard and the Kiss player. Especially DivX5 users often use one or both of these features and once XviD 1.0 becomes a reality there'll be even more people using this features.. and all of them can't use any currently available hardware player (unless you count an Xbox with modchip and xmp or the PS2 equivalent as hardware players).