As far as I understand, Fremantle mplayer hasn't been optimised yet for the OMAP chipset. VLC has been optimised a bit, it uses NEON, but it doesn't use the DSP.

If one of those players could use both the optimisations and the DSP, I bet we could get 720p video...

Yes, but the screen is not 720p, so we would need more power to scale the video down, along with require extra space for the video.

DVD quality seems idea for the tablets IMO.

So why is the i8910 able to play them but not the N900? Maybe not out of the box, but i think it should be able to handle such vids...

Why was MKV support not built-in? I understand the issues surrounding OGG support, but surely MKV does not have the same issues?

That said I think all the MKV files I have seen are 720p, SD people usually seem to prefer XVID/DIVX than H264. That said I am not even sure why MKV is preferred over AVI or MP4 containers (perhaps MP4 as it has patent issues).

It would be useful if the N900 could play these 720p .mkv files and output the result by DLNA/uPNP. And if you have a TV/Receiver that can receive it and display it.

HD output by composite should be fairly useless, keeping in mind how crap composite is. Showing it on the N900 screen aswell as it is to small to even notice the difference against a lower resolution XviD.

mkv offers chapter metadata, sane vorbis support, sane vfr (variable framerate) support, and softsub support, as well as multiaudio and subtitle support.

vfr is nice for animated content, and softsubs are nice when your target audience is split between those that want subtitles and those that do not.

avi actually has multiaudio too, but few players support it. Vfr and vorbis are also possible, but very few players support vorbis in avi, and even fewer encoders can create it properly. Both vfr and vorbis in avi is horribly inefficient, with huge overhead.

I encoded a bunch of videos for someone on irc with n900. Iirc, h264 only worked if it was baseline, and properly identified itself as baseline. What worked perfectly for 480p didn't work with same settings in 720p, came up with an error message.

I think time is better spent on reporting performance issues, profiling and improving the current gstreamer setup. There are already dsp accelerated mpeg4, h264 base profile, divx, wmv, h263 gstreamer elements on the n900 and I believe at least the h264 one could be made faster and that we'll see 720p files play without much of a sweat. Also with the qos handling in gstreamer it is possible to make the codecs not decode fully and just have macroblocks with same pixel colour when the load is too high and so not skip.

The scaling down is done by the gpu so is not really a cpu drain. however of course working on 720p frames means more memory access etc.

Rygel will export them if you do the tracker-register-mimetype i mentioned in a previous post on thread over dnla/upnp. If you have a dnla client that supports mkv like the new samsung lcds then you will be able to watch mkvs stored on your n900 on your tv.

is there any mkv player now?

This didn't help?