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