let the player do the resizing?

[kilg0r3]

this thread, of course, concerns only peole who are not bothered by 2 or even 3 cd rips.

the codecs like divx and xvid are already so good that about any film with no more than 120 min playing time can comfortably be burned onto two cds. with clean, i.e. low-noise, sources it seems that even one and a half cd :grin: would suffice. leaving one with the feeling to waste bandwidth. on the other hand, we have the frequent claim that particularly the divx codec tends to smooth the picture a bit too much, even with high bitrates.

for this reason, i wanted to see if i could get even more image detail into my rips by giving the codec some more pixels to work with. did that by encoding a anmorphic source pal source (Shadow of the Vampire) but did not resize it during the encode. The image without black bars, hence, had a resolution of 704(cropped)x 512 instead of 704x400. The resizing was done only by the player.

as far as picture quality was concerned, the result was quiet positive. the divx and xvid codec produced very sharp and detailed pictures while not adding too much additional blocks. the only downside for me was that my machine (athlon 700@856mhz) was too slow to play the divx movie while the xvid stream played at about 80-95% cpu usage, which also resulted in some slight jitter.

in my opinion this method is apt for everybody who wants to get the most detailed picture possible while caring too much about the number of cds or some additional blocks. unfortunately, i have neither the hardware nor the time to make extensive testing on this matter. Perhaps somebody else cares and would then post his results her in this thread.

[Acaila]

the codecs like divx and xvid are already so good that about any film with no more than 120 min playing time can comfortably be burned onto two cds.
Make that one CD :D. Two CD's is overkill for only 120 mins.

[kappa]

You can also try oversizing, so that you don't have to worry about aspect ratio correction if some player does not support it.

[raistlin2k]

WHY should the picture quality be better?? When the player resizes the picture it also interpolates for example from 440 lines to 312.

Moreover, encoding takes much longer (more pixels to encode), there is less bitrate for each pixel and so picture quality gets only worse.

I'm also quite sure that a resizer on transcoding way works more accurate than on playback, there is no need for real-time, so resize filter doesn't have to worry about time he has and can take all the time he needs for making a perfect resize.

Raist

[bb]

I'd rather spend the space for an AC3 track instead of MP3. I don't have an audio card with digital out, so I get Dolby Surround during playback, but who knows: one day I might upgrade my audio hardware...

bb

[wlp5]

I totally agree with kilg0r3. Not resizing an anamorphic source will result in better quality. Let's see an example

Suppose the movie is 704x480. Resizing during the encode would get that to 704x368. raistlin2k is not right. A player would not resize the movie real time to 368. It would rather resize to your screen resolution (1024x768 perhaps). Therefore the player always resizes real time. On an anamorphic source however it would have 480 lines to play with rather than 368 therefore resulting in better quality.

Also , if like me, watch movies on your tv, you get to tranfer the movie in anamorphic and let the tv do the resizing. Modern tv resizing doesn't lose any resolution, just compresses the image, so you get even better IQ.

Actually I always play my movies in anamorphic from my pc to tv even those that are encoded in correct aspect ratio. I use DVOBSUB to extend picture to 16:9 (adding small black bars on 2.35 movies), zoom player to resize them to 4:3 (streched image) and then recompress it at the tv. Since as I explained earlier the player always resizes, I don't lose anything on the pc side, and I get to use the cable bandwidth more efficiently "losing" less picture on the way. The result really shows up (if you have a good tv)

[raistlin2k]

I AM RIGHT!

Never heard about possibility to use your graphic adapter in 720x576, TV resolution?! NO resizing is needed on playback!
800x600 shouldn't be used, resizing decreases playback-quality a lot on a TV-set in this resolution, 640x480 is even worse, because you need a much faster CPU for downsizing the movie in realtime than for blowing it up to 800x600 or higher!


On which TV can you use 1024x768, I can only do this on my beamer:) , but even there I can't see an advantage for resizing on playback so I'm used to run the beamer in 720x576 for movie-playback and use XGA only for playing games :cool:

SO, 720x576 is the resolution to go for, go and buy a ATI RADEON, Geforce-chips don't have such a good TV output (they flicker a lot, without crappy TVTool,720x576 can't even be used! CRAP!)

Raist

[wlp5]

Well, you are right about not resizing in 720x576 resolution. But...

1) For monitor use.

If I understand this correctly you suggest to encode in correct aspect ratio and then use 720x576 res to view it, so that the player doesn't do any resizing. That seems ok, but are you sure you get a better result than encoding in full res (anamorphic) and then viewing on a high res (1024 and higher). That way you lose something over the player resizing but you have a higher encoded res to begin with. So if I'm correct on this in your way you get a clear 720x368 , but in the other way you could get more horizontal lines (true resolution) something between 368 and 480 depending on how good the resizing of the original 480 movie to 768 lines is. Of course you would also lose on the vertical by the resizing.

I'm not sure which way is best.
All this, of course, assuming you have excess bitrate for the movie (1cd encodes are out of the question)

2) For TV use, I think there's only one best way to do this. Encode in anamorphic (full res) , view on 720x576 (if your vid card supports it) and send to tv, and let the TV do the resizing.

P.S. I second the use of a Radeon based card. TV out is much better than all other cards.

[kvs]

I have experimented with this before, a good while ago. The conclusion I came to was that it was actually better to resize to real aspect ratio than to keep it squeezed. Although it sounded like a very good idea to virtually keep more of the resolution by keeping it anamorphic and having it resized by player, my frame-by-frame comparison just showed that a resized clip (bicub 0.6) with less resolution but correct aspect ratio blown up to fullscreen on high resolution desktop looked sharper than the anamorphic clip desqueezed onto fullscreen. My testing was only limited, and since I did really want to use the correct aspect size to begin with, I left it at that.
Because I suppose it really could be of potentially higher quality if the desqueezing(resizing) is done better/more correct in the player.. I don't know. And maybe it's subjective as well :)

All I want to say is that test carefully before you decide on anything.

[wlp5]

Keeping it anamorphic was certainly a bad idea, back in the old days (I've been encoding movies since the early days of mpeg2avi). However while your tests could be right, it doesn't make much sense. I don't know which part of the playing process does the resizing but I'm guessing it's the decoder filter. So perhaps a next step to better quality is to make some filters with good resizing (by the way, I'm using ffdshow at the moment).

Could someone who knows more stuff about resizing while playing, tell us a few things?

Since DVDs contain that resolution (and that's the most important reason they look great on my TV), it would be a shame to just throw it away, even if it's only useful for tv viewing.

P.S. By the way, I think my post counter got resetted. Last time I remember it was about 30

[ivanova]

Originally posted by kvs
...my frame-by-frame comparison just showed that a resized clip (bicub 0.6) with less resolution but correct aspect ratio blown up to fullscreen on high resolution desktop looked sharper than the anamorphic clip desqueezed onto fullscreen. My testing was only limited, and since I did really want to use the correct aspect size to begin with, I left it at that....

Just wanted to add that the bicubic resizing has a sharpening effect on video so this could explain why it looked sharper.

I think the issue here should not be the sharpness of the video anyway. This afterall can be done on the fly with the player. The issue has to do with how much information is retained in the video, and keeping the full res and resizing with the player (or tv) will assure the maximum picture information retention.
:eek: