crash log for WebKitWebProcess (pid 15616):

[New LWP 15616]
[New LWP 15626]
[New LWP 15646]
[New LWP 15628]
[New LWP 15627]
[New LWP 15645]
[New LWP 15625]
[New LWP 15651]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/home/clopez/webkit/webkit/WebKitBuild/Release/bin/WebKitWebProcess 16'.
Program terminated with signal SIGABRT, Aborted.
#0  0x00007f52ca89a067 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
[Current thread is 1 (Thread 0x7f52c172ca80 (LWP 15616))]

Thread 8 (Thread 0x7f52637ff700 (LWP 15651)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f52cb1dac7c in _ZNSt18condition_variable4waitERSt11unique_lockISt5mutexE () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#2  0x00007f52d23c9955 in _ZN3WTF10ParkingLot21parkConditionallyImplEPKvRKNS_12ScopedLambdaIFbvEEERKNS3_IFvvEEENSt6chrono10time_pointINSC_3_V212steady_clockENSC_8durationIlSt5ratioILl1ELl1000000000EEEEEE () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#3  0x00007f52d2080842 in _ZN3JSC11JITWorklist9runThreadEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#4  0x00007f52d2080bac in _ZNSt17_Function_handlerIFvvEZN3JSC11JITWorklistC1EvE3$_0E9_M_invokeERKSt9_Any_data () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#5  0x00007f52d23ccaf4 in _ZN3WTFL16threadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#6  0x00007f52d23f633a in _ZN3WTFL19wtfThreadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#7  0x00007f52cf44a0a4 in start_thread (arg=0x7f52637ff700) at pthread_create.c:309
#8  0x00007f52ca94d87d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 7 (Thread 0x7f52c113d700 (LWP 15625)):
#0  0x00007f52cf45118d in nanosleep () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f52d23fdec5 in _ZN7bmalloc4Heap8scavengeERSt11unique_lockINS_11StaticMutexEENSt6chrono8durationIlSt5ratioILl1ELl1000EEEE () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#2  0x00007f52d23fdc42 in _ZN7bmalloc4Heap18concurrentScavengeEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#3  0x00007f52d24000b6 in _ZN7bmalloc9AsyncTaskINS_4HeapEMS1_FvvEE13threadRunLoopEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#4  0x00007f52d23ffd36 in _ZN7bmalloc9AsyncTaskINS_4HeapEMS1_FvvEE16threadEntryPointEPS4_ () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#5  0x00007f52cb1de970 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#6  0x00007f52cf44a0a4 in start_thread (arg=0x7f52c113d700) at pthread_create.c:309
#7  0x00007f52ca94d87d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 6 (Thread 0x7f527a1db700 (LWP 15645)):
#0  0x00007f52ca944d3d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f52cdbba0c4 in g_main_context_poll () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4103
#2  g_main_context_iterate () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:3803
#3  0x00007f52cdbba442 in g_main_loop_run () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4002
#4  0x00007f52d23f86d0 in _ZN3WTF7RunLoop3runEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#5  0x00007f52d23f7d78 in _ZNSt17_Function_handlerIFvvEZN3WTF9WorkQueue18platformInitializeEPKcNS2_4TypeENS2_3QOSEE3$_0E9_M_invokeERKSt9_Any_data () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#6  0x00007f52d23ccaf4 in _ZN3WTFL16threadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#7  0x00007f52d23f633a in _ZN3WTFL19wtfThreadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#8  0x00007f52cf44a0a4 in start_thread (arg=0x7f527a1db700) at pthread_create.c:309
#9  0x00007f52ca94d87d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 5 (Thread 0x7f527b7fc700 (LWP 15627)):
#0  0x00007f52ca944d3d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f52cdbba0c4 in g_main_context_poll () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4103
#2  g_main_context_iterate () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:3803
#3  0x00007f52cdbba442 in g_main_loop_run () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4002
#4  0x00007f52d23f86d0 in _ZN3WTF7RunLoop3runEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#5  0x00007f52d23f7d78 in _ZNSt17_Function_handlerIFvvEZN3WTF9WorkQueue18platformInitializeEPKcNS2_4TypeENS2_3QOSEE3$_0E9_M_invokeERKSt9_Any_data () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#6  0x00007f52d23ccaf4 in _ZN3WTFL16threadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#7  0x00007f52d23f633a in _ZN3WTFL19wtfThreadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#8  0x00007f52cf44a0a4 in start_thread (arg=0x7f527b7fc700) at pthread_create.c:309
#9  0x00007f52ca94d87d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 4 (Thread 0x7f527affb700 (LWP 15628)):
#0  0x00007f52ca944d3d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f52cdbba0c4 in g_main_context_poll () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4103
#2  g_main_context_iterate () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:3803
#3  0x00007f52cdbba442 in g_main_loop_run () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4002
#4  0x00007f52d23f86d0 in _ZN3WTF7RunLoop3runEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#5  0x00007f52d23f7d78 in _ZNSt17_Function_handlerIFvvEZN3WTF9WorkQueue18platformInitializeEPKcNS2_4TypeENS2_3QOSEE3$_0E9_M_invokeERKSt9_Any_data () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#6  0x00007f52d23ccaf4 in _ZN3WTFL16threadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#7  0x00007f52d23f633a in _ZN3WTFL19wtfThreadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#8  0x00007f52cf44a0a4 in start_thread (arg=0x7f527affb700) at pthread_create.c:309
#9  0x00007f52ca94d87d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 3 (Thread 0x7f52789ff700 (LWP 15646)):
#0  0x00007f52ca944d3d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f52cdbba0c4 in g_main_context_poll () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4103
#2  g_main_context_iterate () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:3803
#3  0x00007f52cdbba442 in g_main_loop_run () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4002
#4  0x00007f52d23f86d0 in _ZN3WTF7RunLoop3runEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#5  0x00007f52d23f7d78 in _ZNSt17_Function_handlerIFvvEZN3WTF9WorkQueue18platformInitializeEPKcNS2_4TypeENS2_3QOSEE3$_0E9_M_invokeERKSt9_Any_data () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#6  0x00007f52d23ccaf4 in _ZN3WTFL16threadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#7  0x00007f52d23f633a in _ZN3WTFL19wtfThreadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#8  0x00007f52cf44a0a4 in start_thread (arg=0x7f52789ff700) at pthread_create.c:309
#9  0x00007f52ca94d87d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f527bffd700 (LWP 15626)):
#0  0x00007f52ca944d3d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f52cdbba0c4 in g_main_context_poll () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4103
#2  g_main_context_iterate () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:3803
#3  0x00007f52cdbba442 in g_main_loop_run () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4002
#4  0x00007f52d23f86d0 in _ZN3WTF7RunLoop3runEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#5  0x00007f52d23f7d78 in _ZNSt17_Function_handlerIFvvEZN3WTF9WorkQueue18platformInitializeEPKcNS2_4TypeENS2_3QOSEE3$_0E9_M_invokeERKSt9_Any_data () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#6  0x00007f52d23ccaf4 in _ZN3WTFL16threadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#7  0x00007f52d23f633a in _ZN3WTFL19wtfThreadEntryPointEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#8  0x00007f52cf44a0a4 in start_thread (arg=0x7f527bffd700) at pthread_create.c:309
#9  0x00007f52ca94d87d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f52c172ca80 (LWP 15616)):
#0  0x00007f52ca89a067 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1  0x00007f52ca89b448 in __GI_abort () at abort.c:89
#2  0x00007f52cdbdefc5 in g_assertion_message () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gtestutils.c:2356
#3  0x00007f52cdbdf04a in g_assertion_message_expr () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gtestutils.c:2371
#4  0x00007f52d57a50c1 in owr_video_renderer_get_element () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/openwebrtc/local/owr_video_renderer.c:314
#5  0x00007f52d57a518d in owr_video_renderer_constructed () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/openwebrtc/local/owr_video_renderer.c:360
#6  0x00007f52cdcbf514 in g_object_new_internal () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/gobject/gobject.c:1814
#7  0x00007f52cdcc10d5 in g_object_new_valist () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/gobject/gobject.c:2033
#8  0x00007f52cdcc13e4 in g_object_new () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/gobject/gobject.c:1617
#9  0x00007f52d469feaf in _ZN7WebCore30MediaPlayerPrivateGStreamerOwr15createVideoSinkEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#10 0x00007f52d469f492 in _ZN7WebCore30MediaPlayerPrivateGStreamerOwr4loadERNS_18MediaStreamPrivateE () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#11 0x00007f52d42d9613 in _ZN7WebCore11MediaPlayer23loadWithNextMediaEngineEPKNS_18MediaPlayerFactoryE () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#12 0x00007f52d42d9921 in _ZN7WebCore11MediaPlayer4loadEPNS_18MediaStreamPrivateE () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#13 0x00007f52d3fedf0e in _ZN7WebCore16HTMLMediaElement12loadResourceERKNS_3URLERNS_11ContentTypeERKN3WTF6StringE () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#14 0x00007f52d3fed381 in _ZN7WebCore16HTMLMediaElement19selectMediaResourceEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#15 0x00007f52d3fe5cb8 in _ZN7WebCore16HTMLMediaElement23pendingActionTimerFiredEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#16 0x00007f52d4286fa6 in _ZN7WebCore12ThreadTimers24sharedTimerFiredInternalEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#17 0x00007f52d23f89ea in _ZZN3WTF7RunLoop9TimerBaseC1ERS0_EN3$_38__invokeEPv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#18 0x00007f52cdbb9d8d in g_main_dispatch () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:3122
#19 g_main_context_dispatch () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:3737
#20 0x00007f52cdbba128 in g_main_context_iterate () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:3808
#21 0x00007f52cdbba442 in g_main_loop_run () at /home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/glib-2.44.1/glib/gmain.c:4002
#22 0x00007f52d23f86d0 in _ZN3WTF7RunLoop3runEv () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-4.0.so.18
#23 0x00007f52d3ae7a5d in _ZN6WebKit16ChildProcessMainINS_10WebProcessENS_14WebProcessMainEEEiiPPc () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-4.0.so.37
#24 0x00007f52ca886b45 in __libc_start_main (main=0x400d30 <main>, argc=2, argv=0x7fff3bb3e2b8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff3bb3e2a8) at libc-start.c:287
#25 0x0000000000400c59 in _start ()

STDERR: 
STDERR: warning: core file may not match specified executable file.
STDERR: 56	../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory.
STDERR: **
STDERR: ERROR:/home/clopez/webkit/webkit/WebKitBuild/DependenciesGTK/Source/openwebrtc/local/owr_video_renderer.c:314:owr_video_renderer_get_element: assertion failed: (flip)