I encounter problems when playing H.264 (not tested with others) encoded videos with VLC or others players (tested MPlayer, Totem not playing the video just the sound). I'm sure it's about driver but I don't know how to fix it. I tried to install proprietary drivers from AMD but after rebooting I can't log in (only Terminal). My graphics card is an AMD Radeon HD 8 series. I don't know if it's related, I boot with nomodeset option.
Thanks for your help.

Edit : here the result of :

lspci -nnk



00:00.0 Host bridge [0600]: Intel Corporation Haswell-ULT DRAM Controller [8086:0a04] (rev 09)

Subsystem: Hewlett-Packard Company Device [103c:2164]

00:02.0 VGA compatible controller [0300]: Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a16] (rev 09)

Subsystem: Hewlett-Packard Company Device [103c:2164]

 00:03.0 Audio device [0403]: Intel Corporation Device [8086:0a0c] (rev 09)

Subsystem: Hewlett-Packard Company Device [103c:2164]

Kernel driver in use: snd_hda_intel

00:14.0 USB controller [0c03]: Intel Corporation Lynx Point-LP USB xHCI HC  [8086:9c31] (rev 04)

Subsystem: Hewlett-Packard Company Device [103c:2164]

Kernel driver in use: xhci_hcd

00:16.0 Communication controller [0780]: Intel Corporation Lynx Point-LP HECI #0 [8086:9c3a] (rev 04)

Subsystem: Hewlett-Packard Company Device [103c:2164]

Kernel driver in use: mei_me

00:1b.0 Audio device [0403]: Intel Corporation Lynx Point-LP HD Audio Controller [8086:9c20] (rev 04)

Subsystem: Hewlett-Packard Company Device [103c:2164]

Kernel driver in use: snd_hda_intel

00:1c.0 PCI bridge [0604]: Intel Corporation Lynx Point-LP PCI Express Root Port 1 [8086:9c10] (rev e4)

Kernel driver in use: pcieport

00:1c.1 PCI bridge [0604]: Intel Corporation Lynx Point-LP PCI Express Root Port 2 [8086:9c12] (rev e4)

Kernel driver in use: pcieport

00:1c.2 PCI bridge [0604]: Intel Corporation Lynx Point-LP PCI Express Root Port 3 [8086:9c14] (rev e4)

Kernel driver in use: pcieport

00:1c.3 PCI bridge [0604]: Intel Corporation Lynx Point-LP PCI Express Root Port 4 [8086:9c16] (rev e4)

Kernel driver in use: pcieport

00:1c.4 PCI bridge [0604]: Intel Corporation Lynx Point-LP PCI Express Root Port 5 [8086:9c18] (rev e4)

Kernel driver in use: pcieport

 00:1d.0 USB controller [0c03]: Intel Corporation Lynx Point-LP USB EHCI #1 [8086:9c26] (rev 04)

Subsystem: Hewlett-Packard Company Device [103c:2164]

Kernel driver in use: ehci-pci

 00:1f.0 ISA bridge [0601]: Intel Corporation Lynx Point-LP LPC Controller [8086:9c43] (rev 04)

Subsystem: Hewlett-Packard Company Device [103c:2164]

Kernel driver in use: lpc_ich

 00:1f.2 SATA controller [0106]: Intel Corporation Lynx Point-LP SATA Controller 1 [AHCI mode] [8086:9c03] (rev 04)

Subsystem: Hewlett-Packard Company Device [103c:2164]

Kernel driver in use: ahci

 00:1f.3 SMBus [0c05]: Intel Corporation Lynx Point-LP SMBus Controller [8086:9c22] (rev 04)

Subsystem: Hewlett-Packard Company Device [103c:2164]

08:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8188EE Wireless Network Adapter [10ec:8179] (rev 01)

Subsystem: Hewlett-Packard Company Device [103c:197d]

Kernel driver in use: rtl8188ee

09:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E     PCI Express Fast Ethernet controller [10ec:8136] (rev 08)

Subsystem: Hewlett-Packard Company Device [103c:2164]

Kernel driver in use: r8169

 0a:00.0 Display controller [0380]: Advanced Micro Devices, Inc. [AMD/ATI] Sun XT [Radeon HD 8670A/8670M/8690M] [1002:6660]

Subsystem: Hewlett-Packard Company Device [103c:2164]