> On Sunday 25 October 2009 04:55:36 Steve D wrote:
>
>> Gale Andrews wrote:
>>
>>> | From Steve D <
[hidden email]>
>>> | Sat, 24 Oct 2009 23:07:36 +0100
>>> | Subject: [Audacity-devel] Linux crash when adjusting playback
>>> | speed while playing
>>>
>>>> Gale Andrews wrote:
>>>>
>>>>> | From Steve <
[hidden email]>
>>>>> | Fri, 23 Oct 2009 09:19:28 +0100
>>>>> | Subject: [Audacity-devel] Linux crash when adjusting playback
>>>>> | speed while playing
>>>>>
>>>>>> Ubuntu 9.04, Audacity 1.3.9 / 1.3.10
>>>>>>
>>>>>> To reproduce:
>>>>>> 1) Generate a track
>>>>>> 2) Play
>>>>>> 3) Adjust the "Transcription Toolbar" slider to a slower speed
>>>>>> while track is playing.
>>>>>>
>>>>>> Audacity stops and locks up.
>>>>>>
>>>>>> This is a nasty crash as the entire Desktop stops responding,
>>>>>> requiring "F2 > killall audacity > Enter" (can't even click on
>>>>>> "OK").
>>>>>>
>>>>>> Increasing the playback speed will trigger the crash most of
>>>>>> the time. Reducing the playback speed triggers the crash 10
>>>>>> times out of 10.
>>>>>>
>>>>>> Does not seem to be a problem on Win XP.
>>>>>>
>>>>> I can't actually reproduce that on Ubuntu 9.04 in CVS HEAD
>>>>> Unicode Release from a couple of days ago. I tried both
>>>>> starting playback with the normal Play button and with
>>>>> Transcription Toolbar's own button, and playing a region and
>>>>> playing from the cursor.
>>>>>
>>>>> Are there any other factors such as length of track or region,
>>>>> playback device (ALSA default here) or the value on the toolbar
>>>>> slider before you change it?
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Gale
>>>>>
>>>> Just made a fresh install from cvs with all default settings -
>>>> just the same - still crashes.
>>>>
>>> OK, go to the Keyboard tab of Preferences, choose the "Command"
>>> category and add shortcuts for the last four items (Play at Speed
>>> and *playback speed). Does it still crash if you use the
>>> shortcuts, not the slider?
>>>
>> This gives a marked improvement, though I can still get it to lock
>> up if I go mad with it.
>>
>> I've looked more closely at what I am doing to create the issue and
>> it is when I DRAG the slider that the problem occurs. If I just
>> CLICK on the transcription slider scale, then the track playback
>> restarts from the original cursor position at the new speed (which
>> I presume is the correct behaviour).
>>
>> It looks like a rapid sequence of "change playback speed" commands
>> creates some kind of overflow that locks up Audacity.
>> I've just checked again in Audacity 1.3.7 and I can drag the slider
>> without any problem.
>>
>>
>
> I can reproduce this easily. As far as I can tell, there's no actual
> crash, just a hang. I'm working on figuring out exactly what's going
> on.
>
>
>>> Otherwise, compile with --enable-debug and run Audacity under
>>> gdb?
>>>
>>> gdb -ex run ./audacity
>>>
>>> If there's a crash, gdb will give you a prompt that allows
>>> further investigation. For example, the "bt" command prints a
>>> backtrace.
>>>
>>> See:
>>>
http://www.gnu.org/software/gdb/documentation/>>>
>>> Note, I've never done this, I'm just suggesting this may be the
>>> next step.
>>>
>>>
>>>
>>>
>>>
>>> Gale
>>>
>> Thanks, I'm packing to go away for a few days so I'll look into
>> that when I get back.
>>
>>
>
> Running Audacity (and other X11 apps) in GDB is perilous because of
> keyboard and mouse grabs. I added a section to the wiki about this:
>
>
http://wiki.audacityteam.org/index.php?title=Developing_On_Linux#Problems_with_GDB_and_keyboard.2Fmouse_grabs>
> Actually, the reason all your mouse clicks are getting swallowed until
> you kill audacity is that while you're dragging the slider Audacity
> grabs the mouse, not allowing other programs to get clicks. Because
> Audacity hangs, it never releases the mouse, so you're stuck until you
> kill Audacity. On the Wiki I suggest using a nested X server for
> running Audacity in GDB, and that might also make your life easier
> while testing this bug, since the mouse grab would only affect the
> inner server.
>
>
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