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

[From: Siarhei Siamashka]

Hello All,

I have just uploaded a new build of mplayer (mplayer_1.0rc1-maemo.3) to
garage, which implements some experimental and not yet clean video output
method using hardware YUV colorspace and direct access to framebuffer. It's
not quite usable as framebuffer access is not allowed when running mplayer 
as ordinary user (framebuffer device is owned by root:video with 660
permissions). Also right now there are problems with keyboard input and other
applications may cause some flicker effect (for example clock applet or google
search applet overlap fullscreen video when thay are redrawn). 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.

But having a plain framebuffer access creates an interesting possibility.
Looks like mplayer can coexist with other applicaitons nicely and if they
provide some rectangular area for video output, mplayer can be used from
them in slave mode (http://www.mplayerhq.hu/DOCS/tech/slave.txt). Mplayer
just needs to be extended to accept some command line option or slave option
to specify/change screen region that it will use for video playback. Also I 
noticed that there is some initiative to control video players using d-bus: 
http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2006-December/048067.html
So maybe someone can develop a more advanced gui frontend for mplayer with all
the eye candy and convenient gui controls. Let me know if you are interested
in this idea and need some help or more information from me.

Also thanks to Frantisek Dufka for Epson chip documentation, having full and
reliable information adds a certain level of confidence and encourages
development (I needed a confirmation that Epson chip supports only packed 
YUV formats and no planar formats are really available).

Next come current benchmark results (mplayer_1.0rc1-maemo.3) showing some
recent improvements, you can skip this part if you are not interested.

Tested with the following video file (its first 100 seconds):
VIDEO:  [DIV3]  640x480  24bpp  23.976 fps  779.1 kbps (95.1 kbyte/s)

Without hardware YUV colorspace support (-vo x11):
# mplayer -endpos 100 -benchmark -vo x11 -nosound -quiet
...
SwScaler: using unscaled yuv420p -> bgr565 special converter
BENCHMARKs: VC: 122.215s VO:  90.458s A:   0.000s Sys:   1.769s =  214.442s
BENCHMARK%: VC: 56.9918% VO: 42.1831% A:  0.0000% Sys:  0.8250% = 100.0000%


Now using framebuffer output with YUV422 colorspace (-vo nokia770):
# mplayer -endpos 100 -benchmark -vo nokia770 -nosound -quiet testfile.avi
...
SwScaler: using unscaled yuv420p -> yuyv422 special converter
BENCHMARKs: VC: 121.282s VO:  31.538s A:   0.000s Sys:   1.577s =  154.397s
BENCHMARK%: VC: 78.5517% VO: 20.4267% A:  0.0000% Sys:  1.0216% = 100.0000%

VC - is the raw time it took to decode this video fragment
VO - is the time it took to display it on screen (performing color conversion)
= - is a total time including decoding and displaying (preferably this number 
should stay below 100 seconds is we want to play this video in realtime)

So no playback for 640x480 videos yet, but we got a bit closer to it (and
lower bitrate/resolution videos should be supported better with less battery
power consumption).

Another interesting possibility is to relay video scaling and color conversion
(planer -> packed YUV) to DSP. This method is used by dspfbsink gstreamer
plugin and another nice feature is that dsp tasks are accessibe for ordinary
user. But I'll post some more details and thoughts a bit later in another 
message.