N900 hd video encoding resolution
 

I was reading on the wiki for video encoding on de N900 and it told me that to encode HD content (Lets say 1280 X 720 16:9) the best resolution is 800 X 448 for 16:9 ratios.

In my opinion, this isn't correct.
The N900 has a max resolution of 800 X 450. This is in the 16:9 ratio, so why encode to 800 X 448? Why not use 800 X 450?

I've tried making a new image in photoshop with 1280 X 720, then i resized it to make the width 800, keeping the original aspact ratio. The height output was 480.

Am I wrong, or is the wiki wrong?

Re: N900 hd video encoding resolution
 

-add link to wiki
-n900 max resolution is 800x480

Re: N900 hd video encoding resolution
 

Oh damn, you're right. I made a miscalculation. The resolution from the N900 is indeed 800x480.
Got the wrong info somewhere i think.

But then again, why 800x448? 800x450 is, in my opinion, the better resolution.

Link to wiki: http://wiki.maemo.org/Video_encoding#HD_sources

Re: N900 hd video encoding resolution
 

I´m not sure but it might have something to do with resolution being multiple of 16. Don´t now remember whole thing but well that wiki article is bit of mess and if you have time then please make fixes.

Re: N900 hd video encoding resolution
 

Probably something to do with 8x8, 16x16 blocks that encoders use. I have not enough information on how using resolution that are not clean multiples of 16 affect different encoders & decoders. IIRC I have encoded with 800x450 h.264 and didn't notice anything special.

.edit
Some info here:
http://en.wikipedia.org/wiki/JPEG#Block_splitting

..edit
And more
http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Features

Re: N900 hd video encoding resolution
 

Well im going to convert a lot of mkv's to mp4, so it would be nice to have the optimal resolution.
With 800x448 you are throwing away vertical data; with 800x450 you're not.
But there are no problems with 800x450? the mediaplayer is very picky about it's formats and resolutions...

Then 800x450 = highest resolution for HD content conversion with 16:9 aspect ratio.

Re: N900 hd video encoding resolution
 

I do not know any "perfect" answer for you. Only thing I know is that it seems that encoders use these block while they do their tricks to pack stuff smaller. I don´t know how video resolution that is not multiple of 16 affects the final encoded video quality.

Understandably N900's HW video decoder is limited to screen resolution.

Re: N900 hd video encoding resolution
 

Well thank you for the help.
I'll encode my movies with H264 or Xvid with a resolution of 800x450 because that, is in my opinion, the ideal resolution.

Note: Divx acts buggy on default player(if player reaches end of movie, it will continue to play but keep the last frame of the movie.)

Re: N900 hd video encoding resolution
 

Actaully, the N900 can play videos with a resolution of 848x480 well if you use good settings. I have most of the videos on my N900 in that resolution/quality, though sometimes I also use 700x400.

Someone should try 848x576 widescreen if it works...

Re: N900 hd video encoding resolution
 

How do you record 700x400 videos on the N900? Or did you mean playing?

Re: N900 hd video encoding resolution
 

Most of my movies when scaled end up as 800x336 due to the original films 2.35:1 aspect ratio. If I have a 16:9, I would do 800x448, being closest multiples of 16. As for throwing away vertical data, the whole movie is usually being resized, I think its a decent tradeoff.

Re: N900 hd video encoding resolution
 

And to you quality junkies of resize knock yourself out:
http://forum.doom9.org/showthread.ph...73#post1211873
http://hermidownloads.craqstar.de/vi...ercomparasion/

Re: N900 hd video encoding resolution
 

Because we are dealing with mobile (battery powered) device, the optimal resolution may indeed push towards multiple of 16s if it enables more efficient decoding with CPU and DSP.

I do not know either details enough, but sounds reasonable to have 448 as a vertical resolution because it is multiple of 16.
http://wiki.maemo.org/Video_encoding

Would be interesting though to get real world data of decoding 800x448 vs 800x450 in N900 and monitor the decoded session with powertop.

Re: N900 hd video encoding resolution
 

Ok. I am miffed. I am downloading uTube videos on my PC and wanting them to play on the Nokia N900.

What is the definitive codec or resolution that I should be used to avoid the dreaded "cannot play media format" error?

I just want either a PC program or method to simply be able to port MP4 videos to the N900 without hassles. So far I think the issue comes down to video resolution size, as anything above 800 x 640 seems to be rejected. Is that true?

Is there a simple way of porting videos to the N900 without dread of coder hell? What should I be doing please?

UPDATE

It's all here baby!!

http://wiki.maemo.org/Video_encoding

Phew!

Re: N900 hd video encoding resolution
 

Also, check http://talk.maemo.org/showthread.php?t=77695