Avisynth versus software player bobbing

[trolltuning]

I see a lot of very clever people going to great lengths with Avisynth to de-interlace. Normally I mostly make DV footage I've shot into DVDs. I leave it interlaced which works great for TV. When I play it on computer the software in the player bobs it and everything is fine. So why do some of you de-interlace? Is it just to save space, or do you find better quality by doing it with Avisynth, than by letting the player bob it for you? Am I missing out on something here?:)

[foxyshadis]

A little of both, really. Since most people view them on progressive screens - monitors, or increasingly LCD TVs, a good deinterlace/bob can save space and give a higher quality output. Unfortunately, though systems can handle kernel deinterlacing of SD content fine, HD is still far out of reach without a fast gpu-based deinterlacing (and while purevideo is good, it doesn't stack up to securebob/mcbob or real 60p, for people who care enough about it).

But I imagine it mostly comes down to the bandwidth savings of 30p and simplicity of playing it anywhere.

[Mug Funky]

my preference is interlaced where possible. the only times i'll deinterlace anything are:

- video must be very low bitrate for streaming/downloading
- codec doesn't support interlace (or codec does, but most decoders out there don't, like mpeg-4 ASP).
- source is so whacked-out and badly mastered that the only way to make it watchable is to deinterlace and preserve as much detail as possible.

of course, bob-deinterlacing is another matter - it's essential for standards-conversion and resizing interlaced content. the trick is to re-interlace to your destination framerate. in these cases i swap between leakkernelbob and tdeint, depending on how quickly i need something vs how much care must be taken to avoid artefacts.