GNOME Bugzilla – Bug 721112
gstreamer produces "scratchy" sound
Last modified: 2014-01-01 22:25:40 UTC
up-to-date fedora 20, x86-64, applications which use gstreamer produce "scratchy" sound: playing a movie, listening to music. mpv with direct pulseaudio backend does not produce "scratchy" sound.
Does this happen with any type of file or just some? (mp3, ogg/vorbis or webm) How about: gst-launch-1.0 audiotestsrc ! audioconvert ! pulsesink ? What version of GStreamer is this with? What version of liborc is being used? Have you filed this against Fedora's bug tracker as well?
I got scratchy sounds with .mkv video with an aac audio track, .flac audio files, .mp3 audio files, .ogg files with a vorbis audio track. gst-launch-1.0 audiotestsrc ! audioconvert ! pulsesink does produce scratchy sound (quite less than "normal" audio). fedora 20 up-to-date means: gstreamer-0.10.36-6.fc20.x86_64 and orc-0.4.18-1.fc20.x86_64 downstream bug report is here: https://bugzilla.redhat.com/show_bug.cgi?id=1046969
Do you also get this with other software that is not using GStreamer, e.g. vlc?
I used the other software: mpv
Do you also get this if you run (in which cases does it work, in which not? always just scratchy sound or other problems?): > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=S32LE,rate=44100,channels=2" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=F32LE,rate=44100,channels=2" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=S16LE,rate=44100,channels=2" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=S32LE,rate=44100,channels=1" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=F32LE,rate=44100,channels=1" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=S16LE,rate=44100,channels=1" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=S32LE,rate=48000,channels=2" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=F32LE,rate=48000,channels=2" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=S16LE,rate=48000,channels=2" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=S32LE,rate=16000,channels=2" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=F32LE,rate=16000,channels=2" ! pulsesink > gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! "audio/x-raw,format=S16LE,rate=16000,channels=2" ! pulsesink
All rate=44100 were scratchy. *None* of rate=48000 and rate=16000 were scratchy.
That's useful information. What happens if you play this file with paplay? > gst-launch-1.0 audiotestsrc num-buffers=1000 ! audioconvert ! audioresample ! "audio/x-raw,format=S16LE,rate=44100,channels=2" ! wavenc ! filesink location=test.wav > paplay test.wav
Very few scratches.
more information: the scratches are not consistent (they change location and strenght). mpv played test.wav with 0 scratch.
If paplay also produces scratches I would consider this a problem in PulseAudio or ALSA when doing 44.1kHz playback. mpv maybe resamples or does something else different to the other two.
opened a pulseaudio bug: https://bugs.freedesktop.org/show_bug.cgi?id=73209