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IDProjectCategoryView StatusDate SubmittedLast Update
0002841KdenliveCapturepublic2012-11-19 20:372012-12-28 13:43
Assigned Toj-b-m 
PlatformOSOS Version
Product Version 
Target VersionFixed in Version 
Summary0002841: "Device busy" after first Audio monitor record
DescriptionUsing 64-bit Ubuntu 12.04 and Kdenlive version 0.9.2 from Ubuntu repository, I have occured an issue with audio capture via 'Record monitor'. I can only record audio once using Kdenlive, then the audio capture stops working (it produces silent .wav file, lasting several times longer than recording time).

I have only tested this with M-Audio FastTrack, connected as 'hw:1'. Recording from it via ffmpeg command line works perfectly as many times as I need.
Steps To ReproduceStart Kdenlive with default empty project. In Kdenlive - Configure - Capture, enable the 'Capture audio (alsa)' checkbox, set 'Device' to 'USB audio' (which is hw:1 in my case), and leave 'Encoding' at default 'Normal MPEG'. In 'Record Monitor' window, select 'FFmpeg', disable 'Video', and enable 'Audio'.

Now hit the Record button, recording starts, then hit the stop button. For the first time, this works correctly. However, the exact same thing doesn't work correctly second time. After the Record button is hit second time, Kdenlive keeps printing following to console:
    [alsa @ 0x7f7a64002360] cannot open audio device hw:1,0 (Device or resource busy)
    ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM alsa:hw:1,0
    [alsa @ 0x7f7a64002360] cannot open audio device alsa:hw:1,0 (No such file or directory)
until I hit the stop button.

The audio device remains busy, until I close Kdenlive. Apparently, something about the audio device is not released properly when the Stop button is hit.
TagsNo tags attached.
Build/Install MethodDistribution package
Attached Files

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j-b-m (administrator)
2012-12-28 13:43

Seems to be an MLT issue, I reported it on the mailing list. However in current git I introduced a workaround by adding "default" as ALSA device. For some reason, when selecting this "default" device, the bug is not present and you can record several times in a row.

- Issue History
Date Modified Username Field Change
2012-11-19 20:37 vid512 New Issue
2012-11-19 22:53 j-b-m Assigned To => j-b-m
2012-11-19 22:53 j-b-m Status new => acknowledged
2012-12-28 13:43 j-b-m Note Added: 0008921

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