Video can be better than expected !
 

Hey everybody, i spent some time trying to get the best possible video playback on my N810 ... and managed to get some interesting results.

Most of the forums will tell you that the best definition you can get with smooth playback is something like 400x240. I had some luck to try a lot of different settings and find a better one (to my opinion) :

AVI ; MP4 video ; Single pass ; 640x352 pixels ; 24 fps ; 650 Kbps ; MP3 audio ; 44.1 KHz ; stereo ; 128 Kbps

I encode it on my Mac using Handbrake. It should work as well encoded with another software on a Windows or a LInux computer.

It's good only for 24 fps videos, but it's a lot more detailed than 400x240 and plays perfectly on the default video player. :cool:

EDIT :
HERE IS THE POST WITH THE BEST SETTINGS I GOT (post 40 in this thread):
http://talk.maemo.org/showpost.php?p...9&postcount=40

Re: Video can be better than expected !
 

does this affect CPU usage/battery life a lot? i mean, in comparison, is it worth having the better video quality if it sucks out your battery in 45min or isn't it really that bad?

have you tried scenes with a lot of motion? usually they are the ones that make the video stutter on playback even with moderate bitrates...

Re: Video can be better than expected !
 

I don't believe it sucks so much more battery ... didn't tested it yet but maybe you shouldn't fear so much about it.

For High motion scenes, you have 2 options :

1/ Two passes encoding will use higher bitrate for high motion scenes, giving less or no "Mosaïc" artefacts BUT then the bitrate will be too high for the tablet and the playback jerky on these scenes.

2/ One pass encoding (650 Kbps) will use a constant bitrate, High motion scenes will show some "mosaïc" effect but will play smoothly. The good thing is that scenes with average motion will be very detailed and beautifull on the NIT !

So maybe you should choose your encoding parameters depending on your movie ... if it's pure action style, with lots of exploding things, cars races ... Lower resolution maybe better.

I tested "my" settings on the Ice Age 3 trailer and the result was very good.

Re: Video can be better than expected !
 

Handbrake is awesome for this. People are always astonished at how crisp and smooth video playback is on my N810.

Tim

Re: Video can be better than expected !
 

Meh, I stick with 400x240 simply because I can't see any difference in the video playback above that, save for performance. Of course, I use 2 pass encoding too. hehe.

Re: Video can be better than expected !
 

Virtual dub is good too for this kind of task on Mac OSX, it's a pity it's not available anymore.

Lord Raiden, you really don't see any difference between videos in 400x240 and in 640 x 352 ? For me there is a huge difference in crispness, a lot more details ...

Re: Video can be better than expected !
 

I'm sorry, if we're talking about DVD widescreen ripping, and unless Handbrake is some magic elixir, your numbers suggest that you're robbing Peter to pay Paul. You're encoding a large data set with a relatively low bit rate and you don't mention anything about black band cropping. I have serious doubts or Handbrake is doing more work than you're telling us. Your 640x352 (1.81818) ratio tells me that either you're creating unnecessary artifacts (while encoding) or your distorting the picture (if scaling) or both. Also, from much discussion on this forum, you're most likely sacrificing quality by having any dimension greater than half the screen resolution. I'm happy to be wrong, but for now I don't think I am.

Re: Video can be better than expected !
 

Daperl,
You may be happy soon :D ... to be wrong :D:D:D

I don't think i'm sacrificing quality because i get a lot more details in final video on my N810 than with the usual 400x 240.
Upscaled 640x352 looks a lot better than upscaled 400x240.
The upscaling performed by the tablet is actually quite good, for such a device, it's not just pixel demultiplication, there is some real time treatment here. And it's efficient.

So why stick to a quarter screen definition ? When you watch a DVD on a full HD screen, do you keep it at original size ? Probably not, you upscale it, and, depending on your DVD or BlueRay player (or your screen too), upscaling can be very ugly or very nice ... thanks to the treatment ...

If i didn't mention black band cropping, it's because i think it's obvious. My source was a HD video file and the encoding software proposed me to keep the original aspect ratio. So i didn't distort anything.

You can probably test it by yourself very easily : go on itunes website, download Ice Age 3 trailer in HD, compress it with the parameters i gave in this thread ... and see by yourself.
:D

Re: Video can be better than expected !
 

Okay, I'm an idiot. Do I need QuickTime Pro to save this thing to a file? If so, I'm not sure that works for me. I'm just trying to get the 38MB 420p Trailer 1 file. The youtube trailer I found is only 9MB, so I'm guessing that's not the file you want me to try it on. Help!

Re: Video can be better than expected !
 

http://wiki.maemo.org/Video_encoding
http://wiki.maemo.org/Manual_video_encoding

These cover most everything you need to know about encoding.

Re: Video can be better than expected !
 

Daperl, no, you're not an idiot ... I am ... because, I don't know, maybe you need Qucktime pro to save the file ... (I have it). The sourcefile i chose was the highest quality one : 1080p HD. Re encodig a dirty video would not prove anything, i think.

GeneralAntilles, I read it, but my point in this topic is that it is possible and interesting to go beyond these guidelines ...
It says :
"Video data rate and resolution is limited to about 800Kbps and 400x240 (352x288 on the 770)."

But 640x352 works perfectly for me, and I don't believe my unit has anything special ...

So i wanted to share it ! :D

Re: Video can be better than expected !
 

Ice Age 3 1080p HD trailer: http://movies.apple.com/movies/fox/i...tlrn_1080p.mov Right click --> Save file as...

Yes, because you're lowering the bit rate. Not trying to put you down or anything, though. If you think this is better quality, congrats! And thanks for sharing :)

Re: Video can be better than expected !
 

Well, yes, for me it's better because it keeps a lot more details, even if when everything moves fast ... i can see compression artefacts due to the quite low bitrate for the resolution.

Re: Video can be better than expected !
 

On my mac in Safari and on linux with Firefox I get the same 83 bytes.

Re: Video can be better than expected !
 

Hmm... you're right. What about http://movies.apple.com/movies/fox/i...lrn_h1080p.mov

Re: Video can be better than expected !
 

If you use iTunes to download the trailer, the file should reside somewhere in the iTunes directory on your computer.

Tim

Re: Video can be better than expected !
 

Re: Video can be better than expected !
 

Edit :
I just tried 1 pass, 850Kbps and had very few stutters, so maybe 750 or 800 could do just fine.

Or maybe there is a better choice to make with 2 passes ... it would be nice to limit the bitrate of the second pass ... but i can't do that with Handbrake or VisualHub.

Re: Video can be better than expected !
 

I tried and I tried and I tried. I can't figure it out. I'm guessing you have QuickTime Pro.

Re: Video can be better than expected !
 

You sir, are the sh*t. Thank you.

Re: Video can be better than expected !
 

I also want to mention that 400x240 is the correct aspect ratio for the tablet's screen (1.66 or 16:10) , so it fills the whole screen and looks really good.

640x352 is 1.8 aspect ratio (close to widescreen cinema) not the tablet's aspect ratio, and so it fills less of the screen. (640 * 1.25 = 800, 352 * 1.25 = 440, not 480).

I'd be interested to see you compare apples to apples here. Please crop the width of your video from 640 to 576 and re-encode. It is still not perfect, because it is hard to find numbers that "fit" the tablet's aspect ratio in that range and also meet the "must be divisible by 16" rule that many mp4 players most mp4 encoders require... (EDIT: thanks sjgadsby!)

Re: Video can be better than expected !
 

Ain't got no QuickTimePro here; just right-clicked link in Post #15, saved-as (to my Windows machine) and double-clicked. Maybe you need to clear cache before you try again?

Re: Video can be better than expected !
 

I don't know how I missed that post. There's an hour I'd like back. Thanks to all.

Re: Video can be better than expected !
 

I tried 2 passes again in 640x352, same video.

- At 650 Kbps, plays smooth
- At 800 Kbps jerky on high motion scenes

Re: Video can be better than expected !
 

The divisible by 16 rule isn't an arbitrary choice made by player manufacturers, it's due to the codecs involved. More specifically, it is because the codecs use discrete cosine transformations for spacial compression. Because color channels are subsampled at 4:2:0, their 8x8 blocks actually represent 16x16 areas in the image. So, you get 16x16 macroblocks.

MPEG-4 Part 10 supports other block sizes, if I recall correctly, but I don't know that they provide the same compression efficiency.

Re: Video can be better than expected !
 

Qole, i just respected the ratio of my original video.

I generally prefer having black bands above and under the picture than to crop it and loose a significant part of the image to fill the screen ... For me the reference is the source's ratio, not the screen ...

But it's a matter of taste, i fought a lot with my boyfriend when we had a 82 cm tube TV ... he even used a special mode that stretch the 4:3 picture mainly on the right and left sides ... to fill the screen !!! Soooooo baaaad !!! ;)

Re: Video can be better than expected !
 

totololo: I understand that you're using the original aspect ratio.

But those black bands can affect performance. That's why I wanted to "compare apples to apples" and have you crop your video.

I always crop to the tablet's screen size because a big 4.3" screen full of vibrant video is always a real shock-and-awe experience for people. Especially computer animated kids movies -- they tend to be bigger, brighter and more in-your-face.

PS: I agree with you about stretching 4:3 video to fit a wide screen. That's just WRONG.

Re: Video can be better than expected !
 

Qole, my video doesn'have black bands in it, it's the player that add very thin black bands up and down ... do you think it can degrade performance ? OOOOOH, i will try it !

Re: Video can be better than expected !
 

No, actually, I think the black bands probably are improving performance. The more "unused" screen space that you have, the better the performance.

That's why I'd like to see you crop 5% (32 px) off of both sides of your video; the video will then fill the screen and we can see how high you can push the bitrate with full screen video.

Re: Video can be better than expected !
 

Qole, I tested it :
576x352 (small cropping on both sides)
2 passes
700Kbps

And it runs very well !
The picture is gorgeous, vibrant, full of details. It's even more amazing than with the small black bands up and down.

Except when everything moves very fast : mosaïc, but i find it acceptable, because it's a trailer, it moves a lot more than in the real movie (trailers always are quite epileptic don't you think ?).

Re: Video can be better than expected !
 

Okay, for this particular clip I couldn't have been more wrong. Off the top of my head here's a first stab at a crazy person's explanation:

This is a very high quality computer generated animation for children. All motion and lighting are highly syncopated with smooth accelerations. Almost like a ballet. It's eye candy, not an eye sore. This ain't the "The Blair Witch Project." This kind of stuff is probably a codec's dream. Most of the movements, large and small, seem to be low-order polynomials of shapes of low-order.

I have so much to do, but this high quality footage makes me want to find out where that demon lives.

Re: Video can be better than expected !
 

After some more tests, i finally obtained this setting as the best :
Encoding with HandBrake (mac os) gives a lot less mosaic,
576x352 (slightly cropped on both sides), MP4, 750 Kbps
MP3 44.1 KHz, 128 Kbps

I then get very nice fullscreen and detailed playback.

Qole, thankyou for suggesting 576 instead of 640 ... it was for testing, but finally, it seems to work better than 640 ...

Daperl, what you suggest is very interesting, i suppose a real movie, and even more a "dirty" one would give more compression artefacts, not necessarily a less good performance, what do you think ?

I will try to make another test with a real movie.

Re: Video can be better than expected !
 

Well, final test, I tried with a real movie.
Just converted a chapter of a DVD with Handbrake. I chose a movie with some grainy pictures (Happy Together - Wong Kar Waï). Same settings than before, 576x352 was perfectly fitting the movie without any cropping.
And the result is ...
...
...
Very good !
Not jerky, not blocky ... just nice !

Frankly 576x352 is a loooooot better than 400x240.

Can somebody try and confirm these findings ?

Re: Video can be better than expected !
 

That is very interesting. I would much rather encode for 576x352 if our tablets can handle it. I wonder if the fact that I've been encoding XviD instead of MP4 has anything to do with it?

Re: Video can be better than expected !
 

Maybe ... I noticed that AVI MP4 seems to work better than other filetypes ... don't know why !

Now i'm very pleased by the video ability of the N810 ... it's better than iPod touch !

NIT ROCKS !

Re: Video can be better than expected !
 

I think it's as simple as, "garbage in, garbage out." But animators control every pixel. No need for any blurry image stabilization software. What's funny, is after the first seen, where there aren't any animals, there's no more weather for the rest of the clip. No wind, no clouds and no real contrast. I'm not sure there's one black pixel. When something shakes, everything shakes. Other than that, the backdrop doesn't budge. There's same mild dust when the tree trunk starts rolling, but it's so fine that it's more like haze. They're very stingy with their moving pixels. And the mammoths are easy 'cause they move so slow.

Re: Video can be better than expected !
 

Daperl, I think you are too much negative. :(
Ice Age 3 is supposed to be a fun movie, and the trailer lets hope it really is. It's not supposed to be a show of technical prowess.

Regarding of its ability to be compressed in higher resolution than expected, its nature of 3D movie doesn't change anything, it works the same on our tablets with a real movie too. :cool:

I'm happy that we can finally have better video support, because the "official" guidelines doesn't provide a very good quality. :D

Aren't you happy too ? :confused:

Re: Video can be better than expected !
 

I'm not negative; I'm fascinated. Yes, I'm happy. Thanks for starting this thread.

Re: Video can be better than expected !
 

You are welcome.

I learnt so much in this forum to help me use my tablet, I would be happy to share any usefull information too !

Re: Video can be better than expected !
 

I made some extensive testing at home these 2 last days.

Here are the resolutions that worked well for me, depending the source video format (ratio and framerate)

For sources at 24 or 25 fps (24 is cinema, 25 is PAL video)

16:9 > 576 x 352
Wide > 640 x 272
4:3 > not tested


For sources at 30 fps (NTSC video)

16:9 > 480 x 288
Wide > 576 x 240
4:3 > 400 x 304

Encodings with Handbrake, from various DVD i have.
File were encoded to AVI with MP4 video
2 passes can be used, but bitrate should be kept as low as possible, around 600 to 750 kbps for video
(I prefer to keep single pass, because 2 passes will sometimes exceed the maximum bandwith ang give somewhat choppy video in full screen high speed action).
All audio was 44.1 MP3 128 Kbps