cannot play video

[lightmtl]

After my tablet upgrade 5.1.1, it can not play video. It can only play the video I saved before update. I am Montreal canada. There is no repir center , so I can not get flash tool to downgrade.  Any one can help me ? 

[lightmtl]

I just bought a new Z3 tablet from ebay for over one month. I do not use earphone often.  Yesterday suddenly I hear the radio frequency "click" noise come from my right side of the earphone as soon as plug in the headphone jacket.   I tried HTC earphone, the problem keeps the same. But as soon as music or video starts, the click noise is gone. It is very annoying.  Very strangly, if I use my BOSE noise cancellation headset, once it was turned on, I could not hear this noise even though the tablet is on silence. 

Anybody know how to fix this problem ? Thanks.

[Uliwooly]

@lightmtl

can you recreate this on safe mode?

[Phy]

Do you have Ok Google from any screen on?

[Phy]

1. settings
2. language & input
3. Google voice typing
4. Ok Google detection
5. From any screen
6. Turn it off

[lightmtl]

I turned off OK  Google, problem still exist. As soon I turn on the table, i can hear the click noise. 

How can i downgrade to 4.x , i think it related to upgrade, I can not downgrade any more once I update to 5.11, even I have done reset .

[Uliwooly]

@lightmtl

You could contact your Local support or use flashtool to downgrade.

[Uliwooly]

@lightmtl

can you play the video on a computer?

[Uliwooly]

@lightmtl

I've merged the threads bc you want to downgrade 

[lightmtl]

Yes, I can. it can play the video I saved before upgrade, no matter what format. Most of my vidoe are .mkv hd file, after i transfer them to my tablet, i am not able to play them.  Before the transfer, the tablet will tell me format not support, and ask me if i continue. I chose continue anyway, so it actually played by VLC player. Now it does not work anymore.  

Thank you uliwooly