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?