Author Topic: Sound with clicking noise  (Read 5980 times)

Offline odin4242

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Sound with clicking noise
« on: September 18, 2012, 07:56:36 »
Hi Marten,

i compiled the latest version yesterday evening. Since i use an HDMI to DVI Converter i play the sound through the analog jack. On some channels i have a clicking noise that get worse in the course of time. Switching channels usually solves the problem for a short time.  I'll have a look in the debug.log next time i try. I deactivated the SD Deinterlacer and had the feeling, that it was a bit better. But the clicking is audible on HD channels, too.

Do you have any idea? Is there a similar problem with HDMI output?

Thanks for all your efforts
Till
M3N78-VM | 64GB SSD + 2TB WD Green | NetCeiver 2xDVB-S2-Dual 1xDVB-S Dual | SoftHDDevice
LG 37" Full-HD per HDMI
MediaMVPs | WinVDRStreamer | SMT 7020s | Raspberry Pi
easyVDR 1.0

Offline MartenR

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Re: Sound with clicking noise
« Reply #1 on: September 18, 2012, 13:45:36 »
Quote
Do you have any idea? Is there a similar problem with HDMI output?
No there is no problem with HDMI audio, I solved a few problems at weekend.

It may be that the audio buffers runs empty, this is normally a clicking noise.
I did not try analog audio before, may be the hardware is not buffering so much audio as in the hdmi case.

The analog audio is handled by a pwm modulator in the graphics chip, may be there is a load problem.. I do not know, I have to try this myself, there are multiple stages were it can happen.

But before can you first try, if it is really an analog audio issue so please test with hdmi.

Marten

Offline davep

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Re: Sound with clicking noise
« Reply #2 on: September 19, 2012, 17:47:12 »
There is a new release of firmware for the RPi which is claimed to give improved audio quality through the analogue output as well as fewer clicks.

http://www.raspberrypi.org/archives/2008

Technical discussion on the audio problems is here:
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=38&t=10538

Offline odin4242

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Re: Sound with clicking noise
« Reply #3 on: September 19, 2012, 20:21:49 »
I tried to update my Pi with apt-get update and apt-get upgrade but unfortunately that killed my /boot on the SD card...
That finishes my testing for today since the download will take another 2 hours  :o

With HDMI sound is fine, but the volume control is not working.

I traced the clicking on the analog jack with debug logging, but found nothing. The ffmpeg is printing "incorrect frame size" over and over again to the console, but that seems to be a known thing (googled it)

So next try in a few days when the SD card is ready again.

Till
M3N78-VM | 64GB SSD + 2TB WD Green | NetCeiver 2xDVB-S2-Dual 1xDVB-S Dual | SoftHDDevice
LG 37" Full-HD per HDMI
MediaMVPs | WinVDRStreamer | SMT 7020s | Raspberry Pi
easyVDR 1.0

Offline odin4242

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Re: Sound with clicking noise
« Reply #4 on: September 20, 2012, 20:35:04 »
So,

the new Wheezy Image is installed and it's much better! The OSD is more responsive and the analog output is ok now.
Now, how about HD Deinterlacer for Servus TV? ;)
M3N78-VM | 64GB SSD + 2TB WD Green | NetCeiver 2xDVB-S2-Dual 1xDVB-S Dual | SoftHDDevice
LG 37" Full-HD per HDMI
MediaMVPs | WinVDRStreamer | SMT 7020s | Raspberry Pi
easyVDR 1.0

Offline MartenR

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Re: Sound with clicking noise
« Reply #5 on: September 21, 2012, 06:48:49 »
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Now, how about HD Deinterlacer for Servus TV?
Well you can just test it for yourself, replace in Videoomx.cc
Code: [Select]
        if (deinterlace!=0 && demux->getHorizontalSize()<=720) { with
Code: [Select]
       if (deinterlace!=0 /*&& demux->getHorizontalSize()<=720*/) { then you can see if it works, but I doubt it, since it seems that no internal communication is used for the deinterlacer in image_fx.
This is only a quick hack and not the way it should be implemented, since in this way also 720 p is deinterlaced.

Marten

Btw. one solution is to use 1080i as video mode, another solution might be to not use fullscreen mode, it seems that some kind of deinterlacer is also activated then....
« Last Edit: September 21, 2012, 07:02:50 by MartenR »