[1001PX, Realtek ALC269, Green Headphone Out, Rear] Playback problem

[Francois Lambert]

When watching a movie (with Totem or VLC) and using headphones, I have the music and effects soundtracks correctly but not the language sountrack, or very weak.
I don't have the same problem when using internal speakers.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: alsa-base 1.0.25+dfsg-0ubuntu4
ProcVersionSignature: Ubuntu 3.19.0-42.48~14.04.1-generic 3.19.8-ckt10
Uname: Linux 3.19.0-42-generic i686
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: francois 1408 F.... pulseaudio
CurrentDesktop: XFCE
CurrentDmesg:
 [ 25.429481] init: plymouth-upstart-bridge main process (1046) terminated with status 1
 [ 25.429607] init: plymouth-upstart-bridge main process ended, respawning
 [ 190.184159] atl1c 0000:01:00.0: atl1c: eth0 NIC Link is Up<100 Mbps Full Duplex>
 [ 190.184189] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
 [ 241.433378] perf interrupt took too long (2520 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
Date: Thu Dec 24 17:29:41 2015
InstallationDate: Installed on 2015-12-24 (0 days ago)
InstallationMedia: Xubuntu 14.04.3 LTS "Trusty Tahr" - Beta i386 (20150805)
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:Intel successful
Symptom_Card: Audio interne - HDA Intel
Symptom_Jack: Green Headphone Out, Rear
Symptom_PulsePlaybackTest: PulseAudio playback test successful
Symptom_Type: None of the above
Title: [1001PX, Realtek ALC269, Green Headphone Out, Rear] Playback problem
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/07/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0403
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: 1001PX
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: x.xx
dmi.chassis.asset.tag: 0x00000000
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer INC.
dmi.chassis.version: x.x
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0403:bd04/07/2010:svnASUSTeKComputerINC.:pn1001PX:pvrx.x:rvnASUSTeKComputerINC.:rn1001PX:rvrx.xx:cvnASUSTeKComputerINC.:ct10:cvrx.x:
dmi.product.name: 1001PX
dmi.product.version: x.x
dmi.sys.vendor: ASUSTeK Computer INC.