android media framework 1

1.mfw has a graph
2.graph has nodes
3.nodes are source or sink they are encoder,decoder,parser,modifier
4.source or sink are software or hardware
5.frame comes from source and goes into sink
6.frames are put into command queue of each node
7.each hw/sw node has upper edge OMX interface
8.a node is a .so
9.init is done using .cfg files
10. .so contains cfg i/f, omx wrapper,
11. every .so contains player engine, player driver invoke this engine

12.fw searches ./system/etc/01_Vendor_ti_omx.cfg for hw codec
not found uses SW codecs from PVOMX components (picked up by ./system/etc/pvplayer.cfg)
You can disable Hardware acceleration by editing this file: platform/vendor/ti/zoom2/BoardConfig.mk
take a look at the supported OMX roles (tComponentName): platform/hardware/ti/omx/system/src/openmax_il/omx_core/src/OMX_core.c

13.hardware codec === hardware accelerators
14.they are different from display accelerators

android media framework

1.
level 1 -- MIO source/sink
level 0 -- OMX source/sink (decoder)
level -1(sink) -- surfaceflinger,audioflinger
level -1(source) -- raw hw,encoded stream,decoded stream,hw
2.MIO is like switch box
3.playback is determined by global clock and stream packet timestamps,at any momemt the timestamp
has to be in sync with relative clock value

gstreamer and android

1.get some version of android
2.get the gstreamer port
3.integrate
4.connect to android using adb
5.start gst-launch on adb
6.the video will appear on the android screen on the emulator

Desired checkpoints in android media framework
1.from source store stream into file
2.from file send stream into sink
3.list available sinks
4.list property of source stream
5.list relation between software sink and hardware sink and its properties

basics of audio and video

1.useful apps
mplayer
mencoder
aplay
arecord
amixer
2.stack
mythtv
alsa v4l
oss capture cards(/dev/video)
capture cards(/dev/dsp)
capture cards(/dev/master,/dev/mixer)

3.hardware cards encode raw stream and give back encoded format packet(mp4)
4.hardware has adc,dsp
5.a mixer is associated with a single audio card



6.the codec softwares are stored in specific folders in linux,all standard players will look
for them in these folders.It has both hardware and software codecs.

7.capture cards has analog inputs as wav,digital out as mp3,analog out as ac3, digital in as h264 etc

8.all hadware codec capture cards,will defenitely expose one interface through which raw packets can be obtained.

9.a capture card takes raw packet,encodes it and stores temporarily in pc,this is taken and later transcoded and played in player or given over network and routed back to capture card

10./dev/pcmxxx is mixer for individual card,/dev/master is root mixer of alsa made from different /dev/pcmxxx



11.multimedia ---- files, containers, data
files .... /abc.mp4
container ..... mp4
data ....... video rtjpeg/mpeg4,audio mp3

12.
xvid/divx
h264

practical devices

Develpment board ----- Arduino Mega 2560 ------------- price ~50$
uart camera module ----- µCAM529-TTL ------------- price ~4500Rs
uart gprs module --------- SIm300 Module ---------- price ~3000Rs
uart gps module --------- EM-408 GPS module -------- price ~4000Rs

hawk board ----~80$
moxa usb-4uart ---250$
and others

mythtv

1.has 3 software components
mythtv-setup
mythtvbackend
mythtvfrontend

mythtv-setup is run first
input tv tuner card
scan channels
input audio input device -- dsp
then mythfilldatabase

mythtvbackend is run next

in another system mythfrontend is run
in setup recording profile --->check video and audio codec

add a separate video card with S video out and connect to tv

microcotrl,microprocess,multi-cpu,dsp boards and breadboards

1.http://opencircuits.com/Demo_board
2.http://electronics.stackexchange.com/questions/5658/searching-for-atmel-arm-mcu-in-a-breadboard-setup-like-arduino-nano-but-obvio
3.http://www.embeddedrelated.com/usenet/embedded/show/115403-1.php
4.http://www.fpga4fun.com/
5.http://www.signalware.com/dsp/index.php
6.http://e2e.ti.com/support/dsp/tms320c5000_power-efficient_dsps/f/109/p/70468/255817.aspx
7.http://www.futurlec.com/SMD_Adapters.shtml
8.http://www.twinind.com/catalog_detail.php?id=163
9.http://sm-breadboard.eu/
10.http://8515.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=88345&view=next
11.http://thedailyreviewer.com/hardware/view/minipci-breadboard-fpga-111146072
12.http://www.electronics-related.com/usenet/design/show/142861-1.php
13.http://www.edaboard.com/thread19226.html