crash when we do seek on mpv using mvtools

[4re]

This comes from this issue: mpv-player/mpv#1168

I got this debug info, not sure if anything there is really useful:

#0  0x00007ffff240be89 in raise () from /lib64/libc.so.6
#1  0x00007ffff240d217 in abort () from /lib64/libc.so.6
#2  0x00007ffff2405226 in ?? () from /lib64/libc.so.6
#3  0x00007ffff24052d2 in __assert_fail () from /lib64/libc.so.6
#4  0x00007fffb3b77590 in getReadPtr (frame=<optimized out>, plane=<optimized out>) at ../src/core/vsapi.cpp:64
#5  0x00007fffb2697597 in MVClipBalls::Update (this=this@entry=0x7fff9bffecc0, fn=fn@entry=0x0) at src/MVClip.cpp:92
#6  0x00007fffb26b9b12 in mvflowinterGetFrame (n=<optimized out>, activationReason=<optimized out>, instanceData=<optimized out>, frameData=<optimized out>, frameCtx=<optimized out>, core=<optimized out>, vsapi=0x7fffb3da0800 <vsapi>)
    at src/MVFlowInter.cpp:288
#7  0x00007fffb3b80ece in VSNode::getFrameInternal (this=this@entry=0x21a2a90, n=<optimized out>, activationReason=activationReason@entry=2, frameCtx=...) at ../src/core/vscore.cpp:509
#8  0x00007fffb3b8e318 in VSThreadPool::runTasks (owner=0x1f6f470, stop=...) at ../src/core/vsthreadpool.cpp:165
#9  0x00007fffb3b8f826 in _M_invoke<0ul, 1ul> (this=<optimized out>) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.9.1/include/g++-v4/functional:1700
#10 operator() (this=<optimized out>) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.9.1/include/g++-v4/functional:1688
#11 std::thread::_Impl<std::_Bind_simple<void (*(VSThreadPool*, std::reference_wrapper<std::atomic<bool> >))(VSThreadPool*, std::atomic<bool>&)> >::_M_run() (this=<optimized out>)
    at /usr/lib/gcc/x86_64-pc-linux-gnu/4.9.1/include/g++-v4/thread:115
#12 0x00007fffef9522c0 in ?? () from /usr/lib/gcc/x86_64-pc-linux-gnu/4.9.1/libstdc++.so.6
#13 0x00007ffff70a51b3 in start_thread () from /lib64/libpthread.so.0
#14 0x00007ffff24bd0ed in clone () from /lib64/libc.so.6

This is a script for use with mpv that can reproduce the crash:

import vapoursynth as vs
core = vs.get_core()


clip = src = core.std.BlankClip(clip=video_in, fpsnum=24, fpsden=1, length=3) + \
             core.std.Trim(clip=video_in, first=0, length=500000)

if clip.format.bits_per_sample != 8:
    clip = core.fmtc.bitdepth(clip, bits=8)

sup  = core.mv.Super(clip)
bv   = core.mv.Analyse(sup, isb=True)
fv   = core.mv.Analyse(sup, isb=False)
clip = core.mv.FlowInter(clip, sup, bv, fv, blend=False)

if src.format.bits_per_sample != 8:
    clip = core.fmtc.bitdepth(clip, bits=src.format.bits_per_sample)

clip = core.std.Interleave(clips=[src, clip])
clip = core.std.AssumeFPS(clip=clip, fpsnum=clip.fps_num, fpsden=clip.fps_den)
clip = core.std.Trim(clip=clip, first=5, last=500000)

clip.set_output()

[4re]

This is fixed in vapoursynth/vapoursynth@8ef3b6c