AppImage Audio output


I am working on an AppImage for Kdenlive - a KDE based video editor. I managed to get it mostly work, but I am stuck with audio. I used the scummos/centos6.8-qt5.7 as base docker image.

The video framework used by Kdenlive uses the SDL libraries to output sound, and can be configured to use ALSA, PulseAudio and a few other backends. However, I always get an error message reporting that “SDL failed to open audio: No available audio device”

I tried compiling alsa-lib and even Phonon (using an updated cmake) but I always get this error message.

On the Qt part (less important for us) when the app tries to trigger an audio notification, I get this error:
WARNING: bool Phonon::FactoryPrivate::createBackend() phonon backend plugin could not be loaded
WARNING: Phonon::createPath: Cannot connect Phonon::MediaObject ( no objectName ) to Phonon::AudioOutput ( no objectName )

Does anybody have experience with audio output based on CentOs or advices on how to fix this?

Hi j-b-m,
unfortunately I have no expertise in this area and the problem you are describing doesn’t sound to be specifically coming from AppImage. So you are compiling on CentOS 6 and don’t get sound on CentOS 6, or on other systems? On Ubuntu, for example, the default sound system is PulseAudio, but I am sure you are aware of that.
Sorry I can’t be of more help here - someone else maybe?

Thanks a lot for your answer. I thought maybe there were some environment variables to adjust but as you said in this had nothing to do with AppImage, I just needed to install the alsa-lib-devel package in CentOs and recompile SDL to make alsa sound work. Qt audio not working yet but this is not a priority. So I now have a working Kdenlive AppImage, great!

Congratulations and be sure to test on many (Live ISO) systems.

@j-b-m just a short “thank you” - I’ve been running Kdenlive for some time now. The AppImage made the application accessible to me, and I really like it. Did you get some feedback about the AppImage from other users so far? What did you like about the format, what could we improve?

Thanks for your kind message. I am quite happy with the AppImage format, the only issue I have seen so far is the startup crash on Arch based distros if libselinux is not installed, but that’s not a blocking issue.

I plan to make several updates to the AppImage for users to test the development version before the 16.12 release, so I will probably have more feedback in the next month.

One thing I would love - I think you already launched the topic - is an easier way to distribute / update an AppImage. I would love to see something like or any other similar initiative allowing a centralized and easy way to install/update an app. Anyways, thanks for your great work on AppImage format and as I said I will probably come back with more feedback in the next weeks.