Divx, interlaced or not?

[rdad]

HOw can I tell if my divx file is interlaced or not?

TMPGenc asks me if my source file is interlaced or non-interlaced... but I do not know how to figure this out. Are *.avi and *.mpg usually non-interlaced? Any info? Thanks in advance.

[SupaCoopa]

Yes, I have this question myself too.
Also what about DVD ripped AVIs?
And what about VHS captured AVIs?

Maybe someone can clear all this out?

[RemoteCtrl]

There is no way of knowing that without looking at the content itself. MPEG-2 is the only widely used format that holds the information about whether the source is interlaced or not and if so, which field comes first.

The reason for having this information in the first place is to display the video correctly and to handle both fields separately. If separation is not done, lossy algorithms might introduce artifacts and compression ratio would drop. Only lossless codecs and some M-JPEG codecs are relatively immune. Separating the fields when the source is not interlaced will also reduce compression but the effect is less severe.

Because neither the AVI container nor the DivX codec are interlacing-aware, DivX makes a poor candidate for encoding interlaced content. No DivX file should be interlaced, but unfortunately some are.

Due to lack of container support, interlaced files are usually displayed incorrectly in a computer monitor. Resulting comb effect is easy to recognise, but if it exists in a progressive source the cause is usually telecining. Codecs see no difference between interlacing and telecining but the latter is a reversible process which should be carried out to improve compression.

[rdad]

Thanks for the info RemoteCtrl.

Ok, let me see if I understand u correctly. If the *.avi or *.mpg file displays jerky on the monitor then it is interlaced? And if it displays properly it is non-interlaced?

[RemoteCtrl]

A video file might be jerky for a number of reasons, but I really ment the combing/tearing/fingering effect. See here.