Dan,
Here are the MLT and Sox versions I'm testing. 

Ubuntu 10.04:
   MLT 0.5.4
   Sox 14.3.0
   Frei0r 1.1.22

Ubuntu 10.10:
   MLT 0.5.6
   Sox 14.3.1
   Frei0r 1.1.22

Is there a way for me to get the installed version number of Sox and Frei0r at runtime (via melt or the Python API)?  I have a feeling the solution will involve me removing some of these incompatible features based on the version of Sox and Frei0r and MLT.

Also, I tried your command line example with the echo filter (melt -verbose test.wav -filter sox effect1="echo 0.8 0.88 6.0 0.4"), and it failed in the same way I described before (lots of error messages streaming down the terminal).

Thanks!
-Jonathan

On Thu, Sep 16, 2010 at 7:48 PM, Dan Dennedy <dan@dennedy.org> wrote:
On Thu, Sep 16, 2010 at 3:09 PM, Jonathan Thomas
<jonathan.oomph@gmail.com> wrote:
> Greetings!  OpenShot is preparing to release version 1.2.0 (our next
> version), and we are in the final stages of testing right now.  I just ran
> into some issues with Sox filters not working, and wanted to ask a few
> questions.
> First, is this the correct syntax for applying a Sox effect in MLT 0.5.4?

what is your version of sox? I have 14.3.0 on KXStudio and 14.3.1 on OS X.
Sox keeps changing interface between versions making it difficult to
support. My latest change that could affect this is limited to
versions 14.2.0+, but I only tested it on 14.3.

>> <filter in="0.0" mlt_service="sox" out="240.0" track="2">
>>
>>    <property name="effect1">echo 0.8 0.88 60.0 0.4</property>
>>
>> </filter>
>
> I can use the sox "play" command line to successfully apply the above sox
> effect.  But when using melt (or OpenShot) it gives me the following error
> over and over again, and does not apply the filter:
>>
>> echo: usage: gain-in gain-out delay decay [ delay decay ... ]
>
> Moving on to MLT 0.5.10, using the above syntax seems to cause a
> segmentation fault.  Is there a new XML syntax for applying Sox effects in
> MLT 0.5.10?  Here is some output from gdb, although I'm not sure how helpful
> it will be:
> Program received signal SIGSEGV, Segmentation fault.
> 0x00007fffec023196 in ?? () from /usr/local/lib/libmlt.so.2
> (gdb) backtrace
> #0  0x00007fffec023196 in ?? () from /usr/local/lib/libmlt.so.2
> #1  0x00007fffec0239c2 in mlt_properties_set () from
> /usr/local/lib/libmlt.so.2
> #2  0x00007fffec02426a in mlt_properties_inherit ()
>    from /usr/local/lib/libmlt.so.2
> #3  0x00007fffe40a77b8 in ?? () from /usr/local/lib/mlt/libmltxml.so
> #4  0x00007fffe3d904b5 in ?? () from /usr/lib/libxml2.so.2
> #5  0x00007fffe3d975ab in xmlParseElement () from /usr/lib/libxml2.so.2
> #6  0x00007fffe3d9788a in xmlParseContent () from /usr/lib/libxml2.so.2
> #7  0x00007fffe3d973cb in xmlParseElement () from /usr/lib/libxml2.so.2
> #8  0x00007fffe3d9788a in xmlParseContent () from /usr/lib/libxml2.so.2
> #9  0x00007fffe3d973cb in xmlParseElement () from /usr/lib/libxml2.so.2
> #10 0x00007fffe3d9e57a in xmlParseDocument () from /usr/lib/libxml2.so.2
> #11 0x00007fffe40a43ae in producer_xml_init ()
>    from /usr/local/lib/mlt/libmltxml.so
> #12 0x00007fffec02f25a in mlt_factory_producer ()
>    from /usr/local/lib/libmlt.so.2
> #13 0x00007fffea2baece in ?? () from /usr/local/lib/mlt/libmltcore.so
> #14 0x00007fffea2bb388 in producer_loader_init ()
>    from /usr/local/lib/mlt/libmltcore.so
> #15 0x00007fffec02f25a in mlt_factory_producer ()
>    from /usr/local/lib/libmlt.so.2
> #16 0x00007fffec76954e in Mlt::Producer::Producer(Mlt::Profile&, char
> const*, char const*) () from /usr/local/lib/libmlt++.so.3
> Any thoughts or suggestions would be appreciated.
> Thanks!
> -Jonathan
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