blog-selfprogramming

Tuesday, December 11, 2012 - 08:07:05

guy, would you release a new raspi os / new xbmc which could support airplay & airtunes ?

we all wait that

Sunday, December 16, 2012 - 12:41:31

hello
as time is getting up, it is time to share with you some of my findings regarding XBMC builds.
all the time i build inside of my pi, no cross compile at all. in fact, all i do is inside pi, including source code examination/modification.

if you can, use external HDD. my SD was fried by swap! also, old slow PATA, pulled from some old laptop, work faster compared to my class 10 SD card.
use reliable power supply, not GSM charger. also, use powered USB hub without current limiting on its outputs. do not use USB cables for power lines. i use switching PSU 5V 5A. i shortcut-ed all power lines in my hub. for all external power lines i use at least 0.75 square cables, tied with plugs. if you can, set PSU output to 5.3V or similar.

i use preload. i can’t bet it help for build, but for sure affect boot and other times.
apt-get install -y preload
sed -i ’s/sortstrategy = 3/sortstrategy = 0/g’ /etc/preload.conf

if you can, disable wired lan. this prevent kernel from hanging with strange messages all the time, especially during high HDD loads.
sudo sh -c ‘echo 1-1.1:1.0 > /sys/bus/usb/drivers/smsc95xx/unbind’
i use only WIFI. smsc95xx lan driver dies all the time!!!

use partition swap instead of file. i thing this will speed LD between 1 and 3 times. my swap partition is first partition of my HDD. also i changed my swappiness to 30. create this partition big enough. mine is 3GB… yes, i know …

for build you will need JAVA. yes, now XBMC build require JAWA!
sudo apt-get install openjdk-6-jre

use libboost1.50-dev instead of libboost1.49-dev. along with other bugfixes, it is better optimized and support intrinsics ( no more “swp{b} was deprecated” ).

now you must use new version of libcec. build it locally.

add –disable-libtool-lock to ./configure parameters. it seems to speedup things too. if not, it will not hurt.

instead of copying /opt/vc/include i use ./configure line. i put BEFORE ./configure following:
CFLAGS=”-I/opt/vc/include -I/opt/vc/include/interface/vcos/pthreads”
CXXFLAGS=”-I/opt/vc/include -I/opt/vc/include/interface/vcos/pthreads”
LDFLAGS=”-L/opt/vc/lib” LIBS=”-lbcm_host”
./configure …

in my configure/configure.in i set use_texturepacker=no. this lead to little bigger SD/HDD space usage for uncompressed images, but saves time for compilation and after that XBMC work slightly faster.

for test builds i use external ( last, localy built ) ffmpeg. i thing it can be safely used for production to. to be able to compile with external ffmpeg, you must add PKG_CONFIG_PATH=/usr/lib/pkgconfig line again before ./configure.

most likely i miss a lot of optimisations i made, but this is just starting point.

sadly, last XBMC can’t work with ALSA on rpi. yes, i enable it manually bu code modifications with idea to get external audio card with spdif working. both aplay and mplayer works great over spdif, so problem is in XBMC itself. i will continue to work on this. also i am working on patch for EDEN to get it on rasbpi. i like it more that FRODO and hope it will play thry spdif, as it do not use socalled AudioEngine.
from user perspective ( and not only ), last git version of frodo do not offer something realy better compared to your last build. yes, there are a lot of commits, but without any real footprint.

happy building!

Friday, December 21, 2012 - 16:41:54

Is it possible you share your newest build with us? :–) thanks.

Friday, December 21, 2012 - 16:54:08

Sounds great, thanks!

Friday, December 21, 2012 - 17:10:01

one question. I would like to use a usb soud card (aureon 5.1 mkII) for the 6ch output. Will it be possible to use this soundcard with your compilation? the official raspbmc does it (a usb sound card support ist installed by default since the beginning of december), but the kernel is not installing the right modules. You even can not install raspi-config on this distri. The raspbian installs them without any problems. Or maybe do yu have any tips for me how to get it working? Thanks for your advice.

Saturday, December 22, 2012 - 13:40:16

korzyn, raspbmc creates a ‘new’ player by mixing code of 2 of existing ones and use it for video player. while this idea is not wrong in general, it imposes more limits than it solves. this way they completely eliminate hardware acceleration of audio decoding. this approach works great for pass-through audio, but software decoding of even simple mp3 in pi is problem. for default audio player they set a regular papplayer. my tests with it shows that i get chunky mp3s. it is able to play only 2 channels and decodes even 5.1 ac3 to 2 pcm, ignoring pass-through. other code they use for their ‘new’ player can’t handle mp3 software decoding at all, but works with pass-throughs.
their player is not supported by mainstream. also code they use and papplayer are disabled in mainstream just because pi do not have enough power to deal with software decoding.

real resolution is different. i know where the problem lies, but i don’t have knowledge with used technologies and linux at all. i am trying to do something, till now without success. i keep learning in hard way and keep trying.

finally, personally i am not a fen how raspbmc does the things. by creating this new player they break all relations/compatibility with mainstream code. there is a way to do this without breaking anything, but no, they does this in their usual way. also, they integrate some ‘fixes’ in remaining code, which again break any relations/compatibility and are not clear if works at all. till now i get only troubles from them, and decided to forget about them. all the time for all the mess they do they pretend that problems are in their users, venting all of his gall and haughtiness on them, while it is clear that raspbmc made problems. i can speak long time about this, but it doesn’t worth. i am developer, not just usual user, i can see root of such things. i thing people at mainstream agree with me, that is why they do not accept ( poor ) fixes from raspbmc team in their repository.