Video Playback virtually impossible on Neo Freerunner? (Re: Video of Qt 4.4 on Neo1973: brings iPhone like graphics)
Carsten Haitzler (The Rasterman)
raster at openmoko.org
Mon Apr 28 03:47:21 CEST 2008
On Mon, 28 Apr 2008 03:09:51 +0200 ramsesoriginal <ramsesoriginal at gmail.com>
> I'm not an expert, so maybe this question is silly, but it just popped
> to my mind: using mencod, couldn't you decode the video, store it in
> decoded form and then you have onyl to copy it? If this would be
> possible, you cold make some sort of video-transfere-applciation where
> you can set the desidred speed/size/ratio..
> again, i have no idea if it's possible, just 2 thoughts from my side..
yes. that's possible. of course your 100mb movie file becomes about 1-2gb
now :) maybe more...
in theory u should manage 512x384 at 24fps (24fps is movie framerate in the
cinemas). as u have almost no decode (though you have to read it from some IO
souce). so u need an IO source that can stream 7mb/sec to you (good luck
finding that!) but *IF* u did... a 2 hour movie would be about 46gb of data...
good luck finding that storage too! :)
in other words... "not practical to have it unencoded to avoid decoding".
i used a 2hr movie just as an example so you know just how much video
compression gets you... it saves an AMAZING amount of space. the numbers for
pure video source (that is zero quality loss original RGB data) is double that
for 512x384 at 24fps. (92gb)...
in the end beyond a "hey my phone is so cool i play high-res video" demos of 30
second clips (that woul still be enormous and u wouldnt be able to store more
than 1 or 2 anyway - but as a demo to show off its enough), it is just not
useful or practical.
yes - we can go for simpler compression schmes that still require decode, but
just less effort and eerything just adjusts. we spend less decode time, but
require more IO bandwidth and vice-versa. once decoded u have a tradeoff of
resolution vs frames per second as the pipe u have to send it down is fixed in
size. you choose your favorite tradeoff, but somewhere there you will need to
Carsten Haitzler (The Rasterman) <raster at openmoko.org>
More information about the community