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Analog audio - stop the popping
02-13-2013, 12:38 PM
Post: #41
RE: Analog audio - stop the popping
I do have a shelved changelist which adds a config.txt property "audio_silence" which basically outputs silence continually (from the GPU side), meaning the audio hardware is never closed/opened.

It didn't fix the popping in all cases(*) for me which is why it got shelved, although it did improve some cases. I imagine it bahaves exactly the same as the method described here (although simpler to enable).

I'll try unshelving it for testing. Although I'd like to fully understand what's going on.

(*) I believe we get 3 pops when at start of audio from omxplayer, and one at end. You get one at start of alsa audio and one at end.
I think one pop in omxplayer is a bug in omxplayer that I think I can fix (it sends a rapid stop/start shortly after opening stream).
One is the expected turning on audio (which may be fixed by holding the audio channel open).
The other one I believe is the transition from audio being open and silence being output, and the switch to first valid samples being output.
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02-14-2013, 01:20 AM
Post: #42
RE: Analog audio - stop the popping
(02-13-2013 12:38 PM)popcornmix Wrote:  I do have a shelved changelist which adds a config.txt property "audio_silence" which basically outputs silence continually (from the GPU side), meaning the audio hardware is never closed/opened.

It didn't fix the popping in all cases(*) for me which is why it got shelved, although it did improve some cases. I imagine it bahaves exactly the same as the method described here (although simpler to enable).

I'll try unshelving it for testing. Although I'd like to fully understand what's going on.

(*) I believe we get 3 pops when at start of audio from omxplayer, and one at end. You get one at start of alsa audio and one at end.
I think one pop in omxplayer is a bug in omxplayer that I think I can fix (it sends a rapid stop/start shortly after opening stream).
One is the expected turning on audio (which may be fixed by holding the audio channel open).
The other one I believe is the transition from audio being open and silence being output, and the switch to first valid samples being output.

I've reverted to using the putsy monitor speakers until this is fixed, using the pulseaudio hack dosnt fix the issue with video skipping.

I installed omxplayer to do some testing and omxplayer test.wav always pops regardless of weather there is another stream playing or not

Willing to alpha test any possible fixs if that would help

It dosn't seem very likly that its fixable above the firmware level at this point but you never know I guess
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02-28-2013, 04:11 PM
Post: #43
RE: Analog audio - stop the popping
Some new info here:
http://www.raspberrypi.org/phpBB3/viewto...40#p299140
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03-04-2013, 01:16 AM
Post: #44
RE: Analog audio - stop the popping
New firmware with improvements for analogue audio popping has been released.

It should be safe to download start.elf and fixup.dat from here:
https://github.com/Hexxeh/rpi-firmware/r.../start.elf
https://github.com/Hexxeh/rpi-firmware/r.../fixup.dat

and replace the ones on boot partition of sdcard (backup the old ones first in case).
Hopefully it will be included on an updated image soon.
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03-04-2013, 01:25 AM
Post: #45
RE: Analog audio - stop the popping
I'll wait for some feedback here, and then move this onto the testing team and then push it as an update. You're probably looking at 3 days.
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03-04-2013, 08:21 AM
Post: #46
RE: Analog audio - stop the popping
(03-04-2013 01:16 AM)popcornmix Wrote:  New firmware with improvements for analogue audio popping has been released.

It should be safe to download start.elf and fixup.dat from here:
https://github.com/Hexxeh/rpi-firmware/r.../start.elf
https://github.com/Hexxeh/rpi-firmware/r.../fixup.dat

and replace the ones on boot partition of sdcard (backup the old ones first in case).
Hopefully it will be included on an updated image soon.


Thx

It works for meSmile
No more popping noise on video start/stop/seek
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03-04-2013, 12:49 PM
Post: #47
RE: Analog audio - stop the popping
I want to confirm the fix as well. No more plopping between audio tracks and skipping in videos becomes a more pleasant experience! Thnx for all the effort!
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03-04-2013, 04:54 PM
Post: #48
RE: Analog audio - stop the popping
Awesome! I didn't hope such a drastic improvement!
Thank you very much for your great effort, Dom Smile

Raspberry Pi 512MB - Super O.C. preset - PSU with solid 5.15V / Raspbmc Release
Sandisk Extreme Class 10 SD card in a USB->SD adapter. :e

Peripherals: Belkin USB Hub, D-Link DWA-131 Wi-Fi adapter, Hama MCE remote via GPIO receiver, PCTV nanostick 73ese DVB-T via VDR
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03-04-2013, 06:19 PM
Post: #49
RE: Analog audio - stop the popping
I also confirm - the pops are gone! Many thanks for all the work on this.

Don't know if it makes a difference, but my existing files were named start_x.elf and fixup_x.dat. I backed these up and copied over the non-x set linked below and another set that I renamed with x's, mostly cuz I don't know better. Smile Not sure which set i uses but one of them works. Rolleyes

Thanks again!
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03-04-2013, 07:21 PM
Post: #50
RE: Analog audio - stop the popping
Pops just once when starting a video after a reboot. Subsequent videos have no popping. My speakers are growling when nothing is playing now.
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