GNOME Bugzilla – Bug 647326
[pulsesink] Produces crackling sound
Last modified: 2011-04-15 17:36:57 UTC
I have been playing multiple 16 bit flac files flawlessly with Banshee over spdif/iec958. But when I try to play 24 bit flac I get a slightly cracking/popping sound. It sounds like playing an old LP record... I have tried multiple 24 bit flac files and they all produce the same result. When playing the exact same files with mplayer the sound is perfect, without any cracking sounds. I hope you can reproduce it. Listen carefully, the cracking sound is relatively quiet, but definitely loud enough to make it unpleasent to listen to.
Can you try with Totem or Rhythmbox (or gst-launch playbin2 uri=..) and see if the problem still occurs? If so, it's a GStreamer issue. If not, do you have a View -> Equalizer enabled in Banshee?
You are right! Exactly the same behaviour in Rhythmbox and gst-launch, so I guess that it is a gstreamer problem. Should have thought about that. How do you handle gstreamer bugs that affect Banshee. Do you close the bug on Banshee and should I open a new bug report on gstreamer? Or do you keep track on the problem by letting this bug refer to the bug on gstreamer?
Changing product to GStreamer
Does this only happen when playing over spdif and does it also happen with other 24 bit audio files? I can't test this here unfortunately
I have tried playing over analog output as well, gives the same result. After I converted the flac-file to wav and ogg the sound from gst-launch was clear, without cracks/pops. However, I was unable to confirm that the audio was still 24 bit. Couldn't find a tool that could verify this.
Does this also happen if you do gst-launch-0.10 audiotestsrc ! audioconvert ! "audio/x-raw-int,depth=24,width=24" ! alsasink and does it go away if you do gst-launch-0.10 filesrc location=/path/to/flac/file ! decodebin2 ! audioconvert ! "audio/x-raw-int,depth=16,width=16" ! alsasink (Please replace alsasink with the sink you're really using)
I didn't manage to get this command to work: gst-launch-0.10 audiotestsrc ! audioconvert ! "audio/x-raw-int,depth=24,width=24" ! alsasink It complains that it "Could not negotiate format" However, both the following two plays nicely: gst-launch-0.10 filesrc location=/path/to/flac/file ! decodebin2 ! audioconvert ! "audio/x-raw-int,depth=16,width=16" ! alsasink gst-launch filesrc location=/path/to/flac/file ! decodebin ! audioconvert ! alsasink While the "standard" way of playing does not: gst-launch playbin uri=/uri/to/flac/file I was surprised to learn that decodebin does the job better than playbin does. I assumed that playbin was using the decodebin logic somehow.
playbin2/playbin is using decodebin internally. The problem here must be caused by something between the decoder and before your sink... or in your sink. It's weird that the pipeline without specifying the audio caps works. Which sink have you set in gstreamer-properties?
Oh never mind. the automatically selected sink works too in your case. What's the output of gst-launch-0.10 -v playbin2 uri=file:///path/to/your/flac/file And I assume this doesn't work either?
Created attachment 185970 [details] Output from gst-launch -v playbin2 uri=... As the output is quite verbose I added it as an attachment. I hope it helps. I noticed that the width was 32, don't know if that has anything to do with this though. And, as you suspected, it does not work any better than playbin.
Ok, then let's try a few other combinations ;) Note that you're using pulsesink, not alsasink. gst-launch-0.10 filesrc location=/path/to/your/flac ! decodebin2 ! audioconvert ! "audio/x-raw-int, signed=(boolean)true, width=(int)32, depth=(int)24" ! pulsesink gst-launch-0.10 filesrc location=/path/to/your/flac ! decodebin2 ! audioconvert ! "audio/x-raw-int, signed=(boolean)true, width=(int)32, depth=(int)32" ! pulsesink gst-launch-0.10 filesrc location=/path/to/your/flac ! decodebin2 ! audioconvert ! "audio/x-raw-float, width=(int)32" ! pulsesink And the same with audiotestsrc instead of filesrc and decodebin2. If one produces cracking sound, does it work if you replace pulsesink by alsasink?
Also good to test: alsasink device=hw:0 - there was a bug a while back in the conversion layers in alsa that caused crackling for some formats/widths.
After having tested the various combinations it seems like the error is in the pulsesink. When using the alsasink (which in turn go to pulse via the alsa plugin) the sound is without crackling. The various audioconversions does not seem to help. Not even when I tried to do a conversion to width=16, depth=16.
If you play something with paplay or a non-gstreamer based audio player that uses pulseaudio, do you still have the problem?
No, when I play using "paplay <flac-file>" the sound is without crackles. The same goes for XBMC which also manages to play the file flawlessly.
Ok, great... could you get the debug output with GST_DEBUG=pulse*:5? For example GST_DEBUG=pulse*:5 GST_DEBUG_NO_COLOR=1 gst-launch-0.10 audiotestsrc ! pulsesink &> log
Created attachment 186040 [details] GST_DEBUG=pulse*:5 GST_DEBUG_NO_COLOR=1 gst-launch filesrc location=... Attached the debug output. There seem to be quite a few underflows... can that be the reason? I counted 126 underflows during the 13 seconds I played. Can't say that I heard that many crackles though.
Which version of gst-plugins-good are you using?
It is the one that comes with Ubuntu 11.04, i.e. 0.10.28-0ubuntu6 I have both a gstreamer0.10-pulseaudio and a gstreamer0.10-plugins-good.
I see, that's a bug in your distro packages unfortunately... added in 0.10.27-1ubuntu1 * debian/patches/07_pulsesink_allow_larger_packets.patch: - allow larger packets to be sent, prevents pulseaudio from crashing on low-end machines See bug #646999 and bug #641072. *** This bug has been marked as a duplicate of bug 646999 ***