Exibir código-fonte para Audio 5.1

http://en.wikipedia.org/wiki/Dolby_Digital


~/.asoundrc
 pcm.!default {
 type plug
 slave.pcm "surround51"
 slave.channels 6
 route_policy duplicate
 }

* retirado de http://linux.p2pforum.it/wiki/Hardware_supportato#Abilitare_l.27audio_5.1


configurando arquivo no formato ac3 com multicanal (de 1 para 5)

com ffmpeg:
 ffmpeg -i l.wav -i r.wav -i sl.wav -i sr.wav -i c.wav -ab 192k -ar \
 48000 -ac 5 -acodec ac3 -y surround.ac3

$ apt-cache show aften
 Description: audio AC3 encoder
 Aften is an audio encoder which generates compressed audio streams based on
 ATSC A/52 specification. This type of audio is also known as AC-3 or Dolby®
 Digital and is one of the audio codecs used in DVD-Video content.
 Bugs: mailto:marillat@debian.org
 Homepage: http://aften.sourceforge.net/


usando:
 sox -M L.wav R.wav C.wav SL.wav SR.wav surround.wav
 aften -b 448 -cmix 0 -smix 0 -dsur 2 -acmod 7 surround.wav surround.ac3

sobre os parâmetros usados acima:
* -b 448 — Bitrate in kbps (4 channels: 384 kbps, 5 channels: 448 kbps)
* -smix 2 — Surround mix level ( 0: -3dB, 1: -6dB, 2: 0 )
* -dsur 2 — (2: Dolby surround encoded, 0: not indicated, 1: not Dolby surround encoded)
* -acmod 7 — Audio coding mode, or channel order (7: L,R,C,SL,SR)

com mplayer.
 mencoder -ovc copy video.avi -audiofile surround.ac3 -oac copy -o newvideo.avi

assistindo em mplayer com 6 canais, usando jack
 mplayer newvideo.avi -ao jack -channels 6
 mplayer -ao jack -channels 5 surround.wav

somente alsa:
 mplayer -channels 6 -ao alsa:mmap:noblock:device=hw=0.1  dvd://4

* retirado de [http://parumi.wordpress.com/2007/12/12/how-to-create-multichannel-51-ac3-audio-and-video-in-linux/ How to create multichannel (5.1) AC3 audio (and video) in Linux]


Mais sobre audio 5.1 no computador
* http://www.hardwaresecrets.com/article/268

Surround Sound
* http://alsa.opensrc.org/index.php/SurroundSound

* [http://www.linuxtricks.net/index.php/archives/121/how-to-set-up-surround-51-audio-in-linux-with-alsa/ How to set up surround 5.1 audio in Linux with Alsa]