Weird artifact playback when using Xvid to decode DX50 Content (AVI)

[ArdenDag]

Hello,

I have a video which was encoded with DirectX 5.0, which Xvid is doing some weird artifacting/blocking during playback.

Attached are three sections which show the problem, it's got me baffled, and it's not the first time it has happened.

1) Changing ffdshow to have DivX decode the video instead of Xvid and playback is fine (screen attached).

2) Gspot confirms the codec, and rendering is successful (screenie also attached)

3) De/Re-muxing does not solve the problem. I tried Avidemux and VirtualDubMod, the fault must be somewhere in the video.

I could change the decoding to DivX and re-encode the video, but I'd rather find the reason this happened. Any insight would be helpful.

Screenies:

Frame 1 (http://arden.netfirms.com/frame1.gif)
Frame 2 (http://arden.netfirms.com/frame2.gif)
Just a random frame further into the video (http://arden.netfirms.com/randomframe.gif)
GSpot capture (http://arden.netfirms.com/gspot.gif)
Random frame during playback with DivX decoding instead of Xvid (http://arden.netfirms.com/divxdecode.gif)

Thanks
Arden

[[P]ako]

DivX and Xvid have strayed away too much. Decode with the decoder of the codec you encoded with.

[ArdenDag]

Is this true? Is Xvid not able to correctly decode all Divx streams and vice versa?

I haven't been on these forums regularly for quite some time (about 4 years), and the time I did leave, Xvid was still in beta, and was touted as better at decoding Divx streams than Divx itself (quite preposterous IIRC)...

In any case, I'd like to know if this is the issue, or not.

Another addition. when I play the video in SMPlayer (front-end for mplayer) I get normal playback. Is that because it doesn't use ffdshow?

Thanks,
Arden

[[P]ako]

Yes, it is true. A lot of water has passed under the bridge in the last four years.

If by normal playback you meant artifact free video playback, then it's because mplayer decodes de video with the proper decoder. Try changing the FourCC to XviD and see how well mplayer does.

[ArdenDag]

Ok, NOW I'm CONFUSED...

I changed the FourCC to XVID (and also to xvid). Both play just like previously when xvid was decoding the content with the DV50 FourCC, inside of WMP9 and MPC... HOWEVER... SMPlayer plays it correctly... And here lies my confusion...???!!!

Is SMPlayer (or mplayer) doing something other than looking at the FourCC code to decide which decoder to use??? Is something else going on??

EDIT: Here is a snapshot from SMPlayer's File Properties... What is this codec used to decode?!?! ffodivx???
http://arden.netfirms.com/smplayer.gif

Arden

[Placio74]

...
What is this codec used to decode?!?! ffodivx???

ffodivx = FFmpeg MPEG-4 = libavcodec

libavcodec library used by VLC media player, The KMPlayer, and ffdshow too (hmm... & Avidemux?).

For decode in VirtualDub, You can use ffdshow VfW or Avisynth script + FFmpegSource.

[[P]ako]

If you have both, DivX and XviD, go and make sure that the configuration of the decoders are like follow:

-DivX: "support decoding of generic MPEG-4 video", unchecked
-XviD: under FourCC support "divx", "dx50" and "mp4v", all are unchecked

If they checked, uncheck them all and try again.