SUMMARY Importing a video clip or opening a previous project causes kdenlive (18.12.3) to hang when using the JACK audio server. DETAILS: After a recent upgrade of Opensuse, from 15.0 to 15.1, I created a new project in kdenlive (18.12.3) and tried to import a video clip which cased kdenlive to hang. I also tried with the 19.12.0a and 18.12.1b appimages from the kdenlive site, with the same issue, i.e. hanging when trying to import video clips. I also tried opening some previously created projects, with similar hangs. When importing clips, I will see the clip name appear in the Project Bin window along with a grey thumbnail and a partially completed project bar just underneath. On one occasion when starting the kdenlive-18.12.1b-x86_64.appimage, I noticed the following line in the console output: 'Switching audio backend to: "sdl2_audio" ' I normally run the jack server for audio applications, with the pulse audio passthrough (JACK D-Bus intrrface to allow pulse applications to go through jack), so I stopped jack, and kdenlive ran correctly. Then, I restarted jack followed by kdenlive and saw kdenlive hang when trying to import a clip. Then, in pavucontrol, I assigned kdenlive to the "Jack sink (PulseAudio JACK sink)" audio device instead of the direct device, and kdenlive un-hung. STEPS TO REPRODUCE 1. start JACK audio server with QJackCTL with the D-Bus Interaface and JACK D-Bus interface options enabled. Otherwise the jackd command line is: /usr/bin/jackd -dalsa -r44100 -p256 -n2 -Xseq -D -Chw:CODEC -Phw:CODEC,0 2. Start kdenlive 3. try to import a video clip OBSERVED RESULT kdenlive becomes unresponsive and must be terminated unless the audio device assignment in pavucontrol is changed to jack sink. EXPECTED RESULT Kdenlive successfully imports the video clip. SOFTWARE/OS VERSIONS OpenSuse 15.1 Linux/KDE Plasma: KDE Frameworks 5.55.0 Qt 5.9.7 (built against 5.9.7) The xcb windowing system ADDITIONAL INFORMATION
Tested here with 20.08.1 linux distro package and with kdenlive-20.11.70-8a08988-x86_64.appimage. jack2 version 1.9.14. Tested with SDL: Pulseaudio (on my system pulseaudio redirects to jack). Works good. and with RtAudio: * 20.08.1 linux distro package: Will work good with direct output to Jack (autodetects and autoconnects to jack's system output) and sound plays correctly. The distinct behavior is that when I select any frame on timeline, it produces continuous noise representing the audio frame. With SDL+pulseaudio it will produce only some ms of noise to do that representation. * kdenlive-20.11.70-8a08988-x86_64.appimage: RtAudio will detect and outputs to ALSA ( and on my system it will be than be redirected do pulseaudio, which sends to jack). I could not select the RtAudio output (it's grayed out). I could not reproduce the described behavior. Also, i didn't understood what you meant when said: > Then, in pavucontrol, I assigned kdenlive to the "Jack sink (PulseAudio JACK > sink)" audio device instead of the direct device, and kdenlive un-hung. Because if kdenlive outputs directly to jack, than Pulseaudio wont see kdenlive. But if kdenlive outputs to Pulseaudio, than I think the only way to the sound to go to jack is through PulseAudio JACK sink. What do you mean when you say "direct device" ?
By "Direct Device", I meant that Kdenlive was being routed, via pulse audio, directly to the audio device. In my case a USB audio device. I had to open pavucontrol and change the device selection from the usb audio device to jack in order to unhang kdenlive. I recognize that most applications, and kdenlive, will not automatically select the pulse-jack sink as the audio device, but I foud it interesting that kdenlive worked until it tried to import. I don't know what audio its trying to generate while importing, may a ding or some other alert bell, but that was the confusing part of this; I couldn't figure out while kdenlive was hanging on an import, and eventually I figured out that it was because jack was running, and kdenlive was trying to use the audio device that was effectively blocked by jack.
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This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!