DivX optimized for TV output

[flooo]

because of the subject of the thread could cover several sections i posted it in this one...

has anyone played with the settings/methods for encoding a dvd to divx? i mainly watch my rips on tv. are there options you can use especially for that?



i'm very interested in these functions:
dvdavi v1.76 -> YUV vs. RGB, TV vs. PC Scale (Speed, Quality on TV)
avisynth v1.0b6 -> resize method like smooth, neutral, etc., the min. resolution for TV playback
virtualdub v1.4.10 -> any filters?
divx v5.02 -> psycho enhancements, pre-propressing

ok, i know, i could test these things on my own... i'm doing this already.. but i often have not the time for that. and maybe some has gathered some experiences here...

flooo

[hakko504]

My experience is that these things partly depends on what TV-out-card you use. I have a Matrox Marvel G400 that works very well for my purposes, i.e. playback on PAL TV. To avoid unnecessary resizing when playing back DivX they should have sizes that are compatible with the TV-out. In my case that means that 352x288 and 704x576 are best suited for 4:3 material. They will be slightly distorted on the computer moniotor but not very much and Zoom player is able to correct this when playing them. For 16:9 material I normally use 704x400 or 512x288. These sizes have also proven to be very good when I play them on TV. For other aspectratios I set the width to 704 and use whatever height that remains after cropping black borders.
I have also on a few occasions used the full 704x576 (crop(8,0,704,576)) and used Zoomplayer/TV-zoom functions to play at correct aspectratio on both TV and computer monitor. This will preserve as much as possible of the original source but requires a LOT of bitrate and I have not really found this to be a good solution: SVCD or miniDVD is better suited for that kind of settings. The inclusion of B-frames in DivX5.02 might have changed this situation though.

As a general rule, I try to use neutral bicubic for resizing. If I need better compression ratios (compresability check in GK) I sometimes change it to soft or simpleresize.
DVD2AVI should be set to YUV & TV-scale. RGB won't work with AVIsynth. TV-scale is preferable as it is better suited for TV. It should also be slightly easier to compress.
If you are using AVIsynth then you should never do any filtering in VD.
I haven't tried the options of DivX5.02 yet, but always use B-frames. They will lower the size of the file considerably without lowering quality. (Try run 2 single-pass-constant-quality encodings of same clip, one with b-frames, one without. Only difference you'll see is filesize.) I am so far very satisfied with the new codec though.

[trbarry]

I don't use TV-out for anything but I guess that won't stop me from jumping in with a dumb question here.

Do any video cards display the hardware overlay over TV-out? I see various posts on aspect ratios for TV etc., and it seems a TV-out user would want to make sure they could take advantage of the hardware scaling using an overlay provides and not have to be using a slower software resize filter.

So, which (any?) video cards can use hardware scaling to TV-out with, say, Zoom Player?

- Tom

[hakko504]

Originally posted by trbarry
So, which (any?) video cards can use hardware scaling to TV-out with, say, Zoom Player?Matrox cards definitively uses HW scaling to TV out. AFAIK this means that only some sizes are valid for TV-out, with a minimum requirement that they are mod-32 horizontal and mod-16 vertical. Zoom player and M$ media player 6.4 are both excellent choises for feeding video to TV-out on Matrox cards.

[avih]

@tom
where have u been?? :) any news with your new deinterlacer?? ;)

about your question, i use tnt2 with chrontel tv-out chip. it does use hardware overlay for tv out. all the major players (except wmpx.x which doesn't support custom AR) support hardware resize (=zoom player, bs player, powerdivx. bs player sometimes use it's own resize algos). the new ffdshow can use various resize and AR methods and it does well. so with ffdshow even wmpx.x can have custom size and ar.

best regards
avi

[trbarry]

Matrox cards definitively uses HW scaling to TV out. AFAIK this means that only some sizes are valid for TV-out, with a minimum requirement that they are mod-32 horizontal and mod-16 vertical

I thought there was some filter like Matrox-fix or something (almost certainly wrong name) that just padded black borders as needed for this. Still much faster than sofware resize. I'm actually using a G400, but don't use the TV-out functions so I haven't played with it.

I was actually asking because I occasionally think about making a fast SimpleResize dshow filter, but since I never use sofware resize on display anyway I haven't really worked up the justification. And I dislike dshow programming because you can't seem to run it in the VS6 debugging IDE. (and because I'm ignorant about it)

- Tom

[trbarry]

@tom
where have u been?? any news with your new deinterlacer??

avih -

Been here, been coding. ;)

Hopefully I'll release a test version this week sometime. I had an Avisynth version mostly working but in creating a DScaler version I broke it. I've rewritten the whole darn thing about 5 times. ;)

- Tom

[avih]

tom, that 'matrox filter' is called 'divxg400' and it can be used with any video card (or codec). it has become a general dshow filter (although still fixes the g400 issues). it has other nice tv-out features as framerate adjustments and more.

if you need dshow debugging method, PM me. i have working debugging method (not interactive though) for our mode2 dshow filter (which i've used also in my xvid postprocessing work).

it's as simple as printf, and u see the output in real time (with debugview).

cheers
avi.

[Emp3r0r]

To jump back to the topic here: First you need to consider the quality of TV you have. If your watching on a 13 inch TV then you could do some low bitrate encodes and still have watchable quality. Recently I watched some very poor encodes (60 meg Family Guy Episodes) on a 24 inch Zenith and even though the quality was pure shit, it didn't look too bad while relaxing in the lazy boy. I laughed my ass off despite the numerous macroblocks and motion artifacts. Generally, TV display is very forgiving and therefore, if encoding just for TV, you can lower your standards from what you would expect to see on your monitor, or any high resolution display. So unless your dealing with very high quality tv's or HDTV's, you can drop the bitrate and resolution of your encodes.