DiVX 5.05, Q=1 and YV12

[xiaphan]

I am doing some rips of Farscape. I generally encode with the DiVX quality option and then mux in ac3 audio b/c I have a lot of hard drive space floating and I also burn some stuff onto DVD-R. Anyway, since I got Divx5.05, I noticed that I can now encode at Q=1 instead of Q=2 (or maybe I just never noticed I could get Q=1). This has generally increased my file sizes from ~900 MB/episode to ~1.5 GB/episode. Also, I have noticed the YV12 stuff from the latest versions of Gordian Knot (i think that's where I got it).

I was wondering:

Is the benefit of that ~3%, but ~600MB of quality really worth it?
Is there a viewable difference between Divx standard and YV12 and which should I use if I have the space for the additional quality?

Thanks.

[KpeX]

Is the benefit of that ~3%, but ~600MB of quality really worth it?

Take a look at the files, and the size of your hard drive, and judge for yourself ;)

Is there a viewable difference between Divx standard and YV12 and which should I use if I have the space for the additional quality?

Umm....not totally sure what you're asking here...in general YV12 refers to a method of encoding in which the colorspace is not changed from dvd --> encoder, which has speed and possible quality advantages.....read more in the avisynth forum....or if I misunderstood what you're asking, my apologies :)

[SeeMoreDigital]

Well xiaphan,

Is the benefit of that ~3%, but ~600MB of quality really worth it?

It's entirely up to you whether or not you think it's worth it. Generally the extra MB size should result in a better quality encode but that's only if you are happy with, 1: the original source and 2: the way your encoder software works.

1.5GB (1536MB) per hour (25.6MB per min) should generate excellent results with DivX.

It's also worth mentioning that with a little tweeking you can even make Mpeg2 look good at these speeds!

[midi]

1.5GB/ep!? How big are the vobs? Encoding barely seems worth it. Personally I would do 3-pass, around 640MB per ep (7 per DVD-R); still plenty of bitrate. But I also encode op/ed separately on my TV eps since those are huge bitrate hogs and will drag down the quality on the rest of the show. In other words, I vote not worth it.

YV12 doesn't really affect quality/ size (besides possibly saving some color conversions). If you're willing to redo all the experimentation to pick proper filters than go for it. But at that insane bitrate you probably don't need to filter much anyway. ^^ I don't think my computer could even play 1.5GB/ep properly. T.T

[XiS]

YV12 sometimes affect quality, especially when you're trying to play them with your directshow renderer (I've never seen any of them which support this format...) or with XMPEG (which invoke a YV12 overlay), you'll see that there is color artifact on pure blue and red colors (Normal!).
When now, if you use this format with DivX or Xvid encoding, it change absolutly nothing seeing the fact that it is the native color space format for MPEG-4 : With YV12 no color space transform, less CPU effort and maximum quality!
But, When WMP or DivX Playa plays the film you will not seen any of the artifacts you have when previewing your film in YV12 : The decoder will interpolate and transform your output frame in YUY2 format. The color information takes 2 times weight in the frame. Basically, it explains why YV12 is not supported by DirectShow renderers (Event the DirectX 9 for Windows XP...)

Conclusion : Use YV12 and enjoy! :)