maemo.org - Talk - mp4 video playback capabilities?

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- Nokia N810 (https://talk.maemo.org/forumdisplay.php?f=28)

- - mp4 video playback capabilities? (https://talk.maemo.org/showthread.php?t=12680)

Re: mp4 video playback capabilities?

Quote:

Originally Posted by Johnx (Post 104121)

jamiepda: This has been covered a couple times before on this forum, which is why you aren't seeing many people chime in. I'll try and answer this in hopes that people searching in the future find this post.
Executive summary: The bandwidth between the CPU and LCD controller on the N800 is the absolute limiting factor of what's theoretically possible. IIRC, 640x480@24fps would be close to the theoretical limit of that bandwidth. (See here for more info.) the N810 is almost exactly the same hardware, with the only real internal changes being some more flash memory, miniSD vs 2x SD, and a GPS, so it shares the same limitation.
Now onto, the good news: The LCD controller can do pixel "doubling" with no performance impact (arbitrary scaling, really). If you're going to transcode anyways, xvid/divx video with mp3 audio works great. 400x240 @ 800Kb/s or so is bulletproof. It looks great on the screen and plays flawlessly even with lots of fast motion. The builtin media player is decent and mplayer is available as well thanks to the excellent work of a forum member named Serge. Mplayer supports a couple of formats the builtin player doesn't and vice versa. AFAICT, one of the big things that might affect playback is actually the audio encoding. MP3 decoding usually happens on the DSP on the N800. Even if it's done in user space there are more than one fixed-point, ARM optimized mp3 codecs available. The situation for other codecs varies but I could definitely see AAC decoding taking siginificantly more CPU power. Anyways, that's someplace to start at least. Hopefully I don't have anything too horribly wrong in there. I'm sure someone will correct me if I do.

-John

Many thanks for the detailed information!

Re: mp4 video playback capabilities?

Quote:

Originally Posted by Johnx (Post 104228)

If you're going to transcode anyways, xvid/divx video with mp3 audio works great. 400x240 @ 800Kb/s or so is bulletproof. It looks great on the screen and plays flawlessly even with lots of fast motion.

Most encouraging news I've heard all day.

Re: mp4 video playback capabilities?

I'm particularly interested in how the n810 plays with Tivo2go. Anyone using this setup? I haven't purchased a Tivo, but I'm strongly considering the new HD box and being able to play the Tivo2go recordings on the 810 without additional transcoding.

Re: mp4 video playback capabilities?

Quote:

Originally Posted by Johnx (Post 104121)

How about H.264 instead of xvid? With everything else being equal (400x240, 800Kb/s, MP3 audio etc) could one still expect good results? In that situation it would just be a bump in CPU usage and not video bandwidth per se. Or would I not likely notice the difference between the two encodes?

I know I could just try it myself, but I'm hoping to start transcoding in advance of my N810 delivery sometime at the end of the month. I have a few hundred movies and TV episodes in full-res xvid and I thought I would get my mythtv box to slowly chew through them all. But I don't want to start that and find out the resulting files are sub-optimal.

I've searched the forum for a "definitive" answer to H.264 playback but can't seem to find one. I do realize that Nokia's manual states support for H.264 at "320x240" but others have suggested larger sizes will work.

Re: mp4 video playback capabilities?

Quote:

Originally Posted by exon (Post 104479)

I've searched the forum for a "definitive" answer to H.264 playback but can't seem to find one. I do realize that Nokia's manual states support for H.264 at "320x240" but others have suggested larger sizes will work.

I'd like to hear experiences with H.264 as well, both in the built in player or mplayer.

H.264 is supposed to give smaller file sizes with the same visual quality, right? :)

Has anyone done extensive testing?

Re: mp4 video playback capabilities?

Quote:

Originally Posted by Johnx (Post 104121)

Hello, what are you using to transcode? I've tried Dr. Divx (original) and Divx Converter, neither worked. Thanks!

Re: mp4 video playback capabilities?

I have no idea about h.264 . If i get a chance, maybe I'll try encodimg something in that format and see how it plays.

I run linux on my desktop so i use a command-line program called tablet-encode to encode things. i also use mediaserv to do on-the-fly converting for when i'm at home watching videos over wireless. apparently nokia released something called media converter for windows that has a nice gui, but i've never tried it.

anyways, what problem are you having with dr. divx?

Re: mp4 video playback capabilities?

Quote:

Originally Posted by weatherman (Post 104294)

Thanks, both to jamiepda for the question and Johnx for the thorough answer.
I'm trying to get some tivo to my device, but the 'cleaned' mp4 is about 1Gb for a 30 min show. I saw a how to convert to ipod, but wasn't sure if I wanted the .5 scaling they suggested. The file doesn't list any details so I don't know the encoding or resoluton even. I'll let you know when I get something that works.

Re: mp4 video playback capabilities?

Quote:

Originally Posted by Johnx (Post 104121)

Prevent this from happening again: Take this information and put it in the Wiki for all to see.

}:^j~
YARR!

Capt'n Corrupt

Re: mp4 video playback capabilities?

Quote:

Originally Posted by Capt'n Corrupt (Post 106061)

Prevent this from happening again: Take this information and put it in the Wiki for all to see.

Except that it doesn't work. Divx isn't a supported format. See the manual page 39.
I'm sure that JohnX's setup works for him, but not with the standard player.

p.s. found an encoder that works; https://garage.maemo.org/frs/?group_id=26
the only option there is bitrate. The rest of his information may still be useful to more advanced users.