AppImage Audio output


#1

Hi,

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?
Thanks


#2

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?


#3

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!


#4

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


#5

@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?


#6

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 store.kde.org 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.