Sound issues with my ATI Radeon HD 400 series on my HP G61 64 BITS.

I installed opensuse13.2 on my 64 Bits HP G61 . I wanted to output the sound to my Yamaha A/V 7.1 receiver through my HDMI port redirected sound to my HDMI and I got sound on my Yamaha receiver . while watching youtube videos ,pulse keeps using ‘PCM’ which was shown on my Yamaha Front panel . but using PCM causes a lot of sound interruption and my receiver front panel displays ‘’ Decoder Off " then the sound is restored and the PCM is displayed on the receiver panel. and it keeps going on …
tried to uncheck pcm in Pulse audio Volume Control and use instead DTS or AC3 or MPEG or EAC3?

“cat /proc/cmdline” gives
BOOT_IMAGE=/boot/vmlinuz-3.16.7-21-desktop root=UUID=a245840d-0753-4437-90af-ccaea765f76c resume=/dev/sda1 splash=silent quiet showopts

“lsmod | grep radeon” gives

  1. radeon 1502833 5

  2. i2c_algo_bit 13413 1 radeon

  3. drm_kms_helper 65670 1 radeon

  4. ttm 93506 1 radeon

  5. drm 335594 8 ttm,drm_kms_helper,radeon
    here is the output of /usr/sbin/ :

can’t I get rid of PCM and use other stable decoder instead ?