[maemo-developers] [maemo-developers] maemo mplayer development and its possible future use on Nokia 770

From: Frantisek Dufka dufkaf at seznam.cz
Date: Mon Dec 11 11:26:08 EET 2006
Siarhei Siamashka wrote:
> Surely all
> these problems can be fixed by implementing hybrid x11/framebuffer code 
> where x11 is responsible for keyboard input and sets video mode so that no
> other application draws over a screen area used by mplayer.

Yes, the result would look like video overlay works in windows or linux 
on PC - overlay draws over different windows when it shouldn't :-) We 
can live with that. As for framebuffer permissions, it may be better to 
relax device permissions than to run mplayer as root.

> I needed a confirmation that Epson chip supports only packed 
> YUV formats and no planar formats are really available

Well, the conversion is done on the fly while the data is transferred to 
internal epson video buffer. I guess it would be hard to do planar YUV 
-> RGB without additional memory. I still don't understand how it is 
done on the fly even in those packed formats since some color 
information (U,V) is common for more lines. Seems like tough task. There 
needs to be additional memory for remembering U,V parts from previous line.

> Another interesting possibility is to relay video scaling and color conversion
> (planer -> packed YUV) to DSP.

I'm not sure, is there some math involved in this or it is just memory 
shuffling? I guess DSP would be really bad for memory shuffling. From 
previous discussions it looks like when you add DSP to the mix all kinds 
of bottlenecks appears. I wonder if gstreamer/dspfbsink could keep up 
with mplayer speed doing just conversion and video output.

Oh BTW, it is off topic but I finally found what that cryptic 'Video 
hardware accelerators for DCT, iDCT, pixel interpolation, and motion 
estimation for video compression' feature on OMAP 1710 page means. Looks 
like the DSP really has some special instructions for performing those 
operations, google for spru098.pdf It is sad that default video player 
is still so bad with such features implemented in hardware.


More information about the maemo-developers mailing list