workaround - green artifacts in xvid & divx avi files

[macstar]

Since ffmpegx version 0.0.9p or so, any video files I encode with mencoder or ffmpegx have been plagued with small, lime-green artifacts that pop up and remain onscreen for several seconds, usually in the darkest area of the screen. They occur right from the outset of a video and throughout it, making it virtually unwatchable.

I have updated ffmpegx regularly, but the problem has persisted, and until this week I had not been successful in finding a workaround. I have no idea why this works, but it works.

Computers: Two iMacs of different varieties, a G4 and G5, using Mac OS X 10.3 [Panther] and Mac OS X 10.4 [Tiger]. The G4 is maxed out at 1gb of memory and the G5 at 2gb.

I had been storing the original videos on the internal hard drives and encoding to an external hard drive.

For some reason, this week, I reversed that - I moved the original video to an external drive and encoded to the internal drive. To my surprise, the problem was solved. No artifacts, better sound-video sync, and even improved sync and hard coding of home-made .srt subtitles. (This was no miracle cure - ffmpeg still has problems with mismatching selected color and font of subtitles, sometimes and unpredictably reverting to the smallest Arial font installed, making the subtitles almost invisible.)

To be sure this was not a fluke, I reinstalled ffmegx on my old G4 and and tried reencoding a video that had failed with these same problems many months ago. Encoding with the original file on the internal drive and the new file on the external yielded the artifacts and sync problems. Encoding with the original on the external drive and the new file on the internal drive yielded a perfect video. This was with a different processor, a different version OS, a different internal drive, and a different external drive.

All settings were identical. The only variable was the drives, internal vs. external.

Can anyone help me understand why this works, or whether I'm missing something here?

Thanks.

Macstar.

[Case]

...small, lime-green artifacts that pop up and remain onscreen for several seconds, usually in the darkest area of the screen. They occur right from the outset of a video and throughout it, making it virtually unwatchable.

Did you try different players?
I have one ffmpegX encoded file (DivX libavc) that shows green artifacts in QuickTime Player, but not in MPlayer or VLC. It may be unrelated to your situation, as the artifacts in my file show every other frame (!) in the same area (horizontal band at 3/4 from the top) for the whole duration, unrelated to brightness.

[macstar]

...small, lime-green artifacts that pop up and remain onscreen for several seconds, usually in the darkest area of the screen. They occur right from the outset of a video and throughout it, making it virtually unwatchable.

Did you try different players?
I have one ffmpegX encoded file (DivX libavc) that shows green artifacts in QuickTime Player, but not in MPlayer or VLC. It may be unrelated to your situation, as the artifacts in my file show every other frame (!) in the same area (horizontal band at 3/4 from the top) for the whole duration, unrelated to brightness.

Thanks for the reply.

Yes, I tried QuickTime Player, MPlayer, VLC, and moving the videos over to my Windoze box, Media Player Classic, among others. Identical results, identical artifacts.

Encoding with the source file on the external drive and the target file on the internal drive yielded no artifacts visible in any player, again, trying the same array of players.

[Huxley]

Try the OpenShiiva forum fix

http://sourceforge.net/forum/forum.php?thread_id=1113616&forum_id=260097