How to debug Gstreamer on Windows

[David Ing]

Since you are switching from mingw to msvc ... watch out for weird issues
with the plugin cache.

http://gstreamer-devel.966125.n4.nabble.com/msvc-build-can-t-find-elements-in-playback-plugin-td4691649.html

On Mon, Mar 30, 2020 at 10:27 AM Daniel Sperka <djsperka at ucdavis.edu> wrote:

> I made an attempt at migrating my build on windows to MINGW, but gave up
> for reasons I cannot remember.
>
> I've wrestled with it, but have stuck with MSVC in my Qt+gstreamer
> application. One issue I ran into that sounds similar to what yours is had
> to do with the scanner running at startup. It searches a hard-coded path,
> but if I use an embedded gstreamer lib I had to set some env variables.
> Here is a portion of my code - the usage is a bit messy and intertwined
> with other stuff.
>
> In my app, I distribute gstreamer libs with the application using the
> *.msm modules. The directory structure is slightly different on
> mac/windows. (I chose not to require a full gstreamer installation when
> installing my application). I had various issues until I got these env vars
> sorted out - my code defines these env vars relative to the location of the
> exe file, and the msm files are installed in a subfolder of the file the
> exe is in.
>
> I distribute a plugin for drawing on a Qt widget (pulled it out of old
> Qt-Gstreamer dist). I put that plugin into the GST_PLUGIN_SYSTEM_PATH
> folder with the official ones rather than create another folder for my
> plugins, so I do not define GST_PLUGIN_PATH here.
>
>
> Dan
>
>
>
> // Initialize gstreamer
>
> // Debug  builds (HABIT_DEBUG) use system-defined gstreamer libs.
>
> // Release builds (HABIT_RELEASE) _can_ use the system-installed (whatever
> we link against) gstreamer libs,
>
> // but the -n flag tells us to run as NOT installed.
>
> //
>
> // When running "installed", we assume that the gstreamer framework is
> embedded in the bundle, and we set two
>
> // env variables to point that direction:
>
> // GST_PLUGIN_SYSTEM_PATH - where gstreamer finds plugins. Note that I
> stick the gst-qt plugin there.
>
> // GIO_EXTRA_MODULES - some glib thing
>
> // GST_PLUGIN_SCANNER - scanner checks local plugin cache??
>
>
> *if* (bNotInstalled)
>
> {
>
> qDebug() << "Run as NOT installed, exe file is " << argv[0];
>
> }
>
> *else*
>
> {
>
> qDebug() << "Run installed, exe file is " << argv[0];
>
>
> //#ifdef HABIT_RELEASE
>
> qDebug() << "exePath " << QCoreApplication::applicationDirPath();
>
> QDir dirScanner(QCoreApplication::applicationDirPath());
>
> QString sRelPathToScanner;
>
> QString sRelPathToSystemPlugins;
>
> QString sRelPathToGioModules;
>
> *#if* defined(Q_OS_MAC)
>
> sRelPathToScanner = "../Frameworks/GStreamer.framework/Versions/1.0/
> libexec/gstreamer-1.0";
>
> sRelPathToSystemPlugins = "../Frameworks/GStreamer.framework/Versions/1.0/
> lib/gstreamer-1.0";
>
> sRelPathToGioModules = "../Frameworks/GStreamer.framework/Versions/1.0/lib
> /gio/modules";
>
> *#else*
>
> sRelPathToScanner = "gstreamer-1.0/libexec/gstreamer-1.0";
>
> sRelPathToSystemPlugins = "gstreamer-1.0/lib/gstreamer-1.0";
>
> sRelPathToGioModules = "gstreamer-1.0/lib/gio/modules";
>
> *#endif*
>
> *if* (dirScanner.*cd*(sRelPathToScanner))
>
> {
>
> qDebug() << "Set GST_PLUGIN_SCANNER=" << dirScanner.*filePath*("gst-plugin
> -scanner");
>
> *qputenv*("GST_PLUGIN_SCANNER", dirScanner.*filePath*("gst-plugin-scanner"
> ).*toLocal8Bit*());
>
> }
>
> *else*
>
> {
>
> qCritical() << "Cannot navigate to relative scanner path " <<
> sRelPathToScanner << " from exePath ";
>
> }
>
> QDir dirPlugins(QCoreApplication::applicationDirPath());
>
> *if* (dirPlugins.*cd*(sRelPathToSystemPlugins))
>
> {
>
> qDebug() << "Set GST_PLUGIN_SYSTEM_PATH=" << dirPlugins.*path*();
>
> *qputenv*("GST_PLUGIN_SYSTEM_PATH", dirPlugins.*path*().*toLocal8Bit*());
>
> }
>
> *else*
>
> {
>
> qCritical() << "Cannot navigate to relative system plugin path " <<
> sRelPathToSystemPlugins;
>
> }
>
> QDir dirGio(QCoreApplication::applicationDirPath());
>
> *if* (dirGio.*cd*(sRelPathToGioModules))
>
> {
>
> qDebug() << "Set GIO_EXTRA_MODULES=" << dirGio.*path*();
>
> *qputenv*("GIO_EXTRA_MODULES", dirGio.*path*().*toLocal8Bit*());
>
> }
>
> *else*
>
> {
>
> qCritical() << "Cannot navigate to relative gio module folder " <<
> sRelPathToGioModules;
>
> }
>
>
> *#ifdef* Q_OS_WIN
>
> QString sRelPathToHabitPlugins("gstreamer-plugins");
>
> QDir dirHabitPlugins(QCoreApplication::applicationDirPath());
>
> *if* (dirHabitPlugins.cd(sRelPathToHabitPlugins))
>
> {
>
> qDebug() << "Set GST_PLUGIN_PATH=" << dirHabitPlugins.path();
>
> qputenv("GST_PLUGIN_PATH", dirHabitPlugins.path().toLocal8Bit());
>
> }
>
> *else*
>
> {
>
> qCritical() << "Cannot navigate to relative Habit plugin path " <<
> sRelPathToHabitPlugins;
>
> }
>
> *#endif*
>
> }
>
>
> // Initialize gstreamer
>
> qDebug() << "Initialize gstreamer...";
>
> *gst_init*(&argc, &argv);
>
> qDebug() << "Initialize gstreamer...Done.";
>
> On Mon, Mar 30, 2020 at 9:28 AM David Ing <ding at panopto.com> wrote:
>
>> FWIW -- The mingw binaries are built with a very old toolchain:
>> https://gitlab.freedesktop.org/gstreamer/cerbero/-/blob/1.16/recipes/toolchain/mingw-w64.recipe#L3
>>
>> On Mon, Mar 30, 2020 at 8:59 AM erikherz <erik at vivoh.com> wrote:
>>
>>> David,
>>>
>>> I will try out this code too ... assuming that simply putting all of the
>>> plugins in the same directory is not sufficient.
>>>
>>> Thank you!
>>>
>>> Erik
>>>
>>>
>>>
>>> --
>>> Sent from: http://gstreamer-devel.966125.n4.nabble.com/
>>> _______________________________________________
>>> gstreamer-devel mailing list
>>> gstreamer-devel at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>>
>> _______________________________________________
>> gstreamer-devel mailing list
>> gstreamer-devel at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>
>
>
> --
> Daniel J. Sperka, Ph. D.
> UC Davis Center for Neuroscience
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
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