Video playback very laggy and no sound

REPRODUCIBILITY (% or how often): always
BUILD ID = OS VERSION (Settings > About product): 4.3.0.12
HARDWARE (XA2, X10, X10 II, …): X10 II
UI LANGUAGE: German
REGRESSION: (compared to previous public release: Yes, No, ?): Yes (but I noticed this behaviour in 4.2 as well before updating to 4.3, however everything worked ok in earlier versions)

DESCRIPTION:

Video playback is very slow / laggy and has no sound. This affects videos in the Gallery app, but also e.g. videos on Youtube (native browser as well as Opera Android app).

PRECONDITIONS:

STEPS TO REPRODUCE:

  1. record a video with camera app
  2. try to watch the video in gallery

EXPECTED RESULT:

the video plays in realtime

ACTUAL RESULT:

very slow playback without sound

ADDITIONAL INFORMATION:

I tried this solution

(store was listed as user added repository, so I removed it) but it didn’t help