[LAU] Using your Nokia N9/N950 as a Dolby surround processor

[Niels Mayer]

[[ Orig from http://forum.meego.com/showthread.php?t=5233&page=2 ]]

In http://karoliinamaemoblog.blogspot.com/2011/12/how-to-use-nokia-n9-as-music-production.html
"How to use Nokia N9 as music production tool - encoding your
sequencer's tracks with Dolby Headphone using the Nokia N9"
I found the following gem:
...............
gst-launch filesrc location=input.wav ! decodebin ! nokiadhmmix !
wavenc ! filesink location=output.wav
...................

~ $ gst-inspect-0.10  | grep mix
pulseaudio:  pulsemixer: PulseAudio Mixer
nokiadhmmix:  nokiadhmmix: Dolby Headphones Mobile mixer
videomixer:  videomixer2: Video mixer 2
videomixer:  videomixer: Video mixer
..................

Anybody know whether this can be used to be able to mix and position
soundsources in the headphones and how effective it is? Seems like it
would significantly offload CPU in music apps on the handset if they
could use the DSP to do some rudimentary mixing, unless you  have to
waste a bunch of CPU packing separate audio streams into a single
multichannel just to get it mixed back to stereo via the DSP....

...............
~ $ gst-inspect-0.10 nokiadhmmix
Factory Details:
Long name: Dolby Headphones Mobile mixer
Class: Filter/Effect/Audio
Description: Nokia AC-3/e-AC-3 decoder
Author(s): Nokia Corporation <multimedia at maemo.org>
Rank: primary (256)

Plugin Details:
Name: nokiadhmmix
Description: Nokia Dolby Headphones Mobile
Filename: /usr/lib/gstreamer-0.10/libgstnokiadhmmix.so
Version: 0.10.0
License: Proprietary
Source module: gst-nokia-dolby
Binary package: gst-nokia-dolby-mobile
Origin URL:

GObject
+----GstObject
+----GstElement
+----GstNokiaDhmMix

Pad Templates:
SINK template: 'sink'
Availability: Always
Capabilities:
audio/x-raw-int
endianness: 1234
width: 16
depth: 16
signed: true
rate: [ 8000, 48000 ]
channels: [ 1, 6 ]

SRC template: 'src'
Availability: Always
Capabilities:
audio/x-raw-int
endianness: 1234
width: 16
depth: 16
signed: true
rate: [ 8000, 48000 ]
channels: 2


Element Flags:
no flags set

Element Implementation:
Has change_state() function: 0x3ab1331c
Has custom save_thyself() function: 0x3ab134e8
Has custom restore_thyself() function: 0x3ab0f9d8

Element has no clocking capabilities.
Element has no indexing capabilities.
Element has no URI handling capabilities.

Pads:
SRC: 'src'
Implementation:
Has custom eventfunc(): 0x3ab27968
Has custom queryfunc(): 0x3ab231cc
Has custom iterintlinkfunc(): 0x3ab22cec
Has getcapsfunc(): 0x3ab4dd28
Has acceptcapsfunc(): 0x3ab236d8
Pad Template: 'src'
SINK: 'sink'
Implementation:
Has chainfunc(): 0x3b0ba7b8
Has custom eventfunc(): 0x3b0b9bbc
Has custom queryfunc(): 0x3ab231cc
Has custom iterintlinkfunc(): 0x3ab22cec
Has getcapsfunc(): 0x3b0b9e08
Has setcapsfunc(): 0x3b0b9868
Has acceptcapsfunc(): 0x3ab236d8
Pad Template: 'sink'

Element Properties:
name : The name of the object
flags: readable, writable
String. Default: null Current: "nokiadhmmix0"
mobile-surround : Enable MobileSurround
flags: readable, writable
Enum "GstNokiaDhmMixMsr" Default: 1, "on" Current: 1, "on"
(0): off - Off
(1): on - On
(2): auto - Auto (on for multichannel streams, off for mono/stereo)
mobile-surround-applied: Indicate current MSR status
flags: readable
Boolean. Default: false Current: false
brightness : MobileSurround timbre effect
flags: readable, writable
Integer. Range: 0 - 4 Default: 2 Current: 2
room-size : MobileSurround envelope effect
flags: readable, writable
Integer. Range: 0 - 4 Default: 0 Current: 0
stereo-matrix-pl2 : Process stereo input as Pro-Logic II encoded
flags: readable, writable
Boolean. Default: true Current: true

-- Niels
http://nielsmayer.com

PS: Also interesting:
http://lists.maemo.org/pipermail/maemo-developers/2011-December/028767.html
--> http://code.google.com/p/gst-dsp/