[x265] Issue #35: Crash when encoding yuv420p10le/yuv420p10be video using ffmpeg (multicoreware/x265)

[sfan5]

New issue 35: Crash when encoding yuv420p10le/yuv420p10be video using ffmpeg
https://bitbucket.org/multicoreware/x265/issue/35/crash-when-encoding-yuv420p10le

sfan5:

Segfaults immediately(before ffmpeg outputs the frame=... status text) when using yuv420p10le.
Segfaults after encoding 25 frames when using yuv420p10be.
I'm not sure whether this is an ffmpeg bug or libx265 bug.

libx265 version: 31731a78d994
ffmpeg version: b2880a3de9e3

Backtrace:

```
#!none

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff23b63b8 in x265::TComPicYuv::copyFromPicture (this=0xa285220, pic=..., pad=0x66c870) at /tmp/build/src/libx265/source/Lib/TLibCommon/TComPicYuv.cpp:291
291	                V[c] = (pixel)((v[c] >> shift) & mask);
(gdb) bt full
#0  0x00007ffff23b62b5 in x265::TComPicYuv::copyFromPicture (this=0xa278c20, 
    pic=..., pad=0x66c850)
    at /tmp/build/src/libx265/source/Lib/TLibCommon/TComPicYuv.cpp:279
        c = 832
        r = 982
        Y = 0x7fffdc518400
        U = 0x130800e0
        y = 0x7fffd904e980
        u = 0x7fffd8d20a70
        mask = 1023
        V = 0x131df120
        v = 0x7fffd8e2c090
        shift = 0
        pady = 9
        padx = 1
        width = 1920
        height = 1080
        rem = 8 '\b'
#1  0x00007ffff23046e4 in x265::Encoder::encode (this=0x66bf30, flush=false, 
    pic_in=0x7fffffffd470, pic_out=0x7fffffffd4c0, nalunits=0x7fffffffd410)
    at /tmp/build/src/libx265/source/encoder/encoder.cpp:323
        pic = 0x117ad820
        curEncoder = 0x66f500
        ret = 0
        out = 0x7ffff4dd74d0 <__GI___libc_malloc+96>
#2  0x00007ffff230aaaf in x265_encoder_encode (enc=0x66bf30, 
    pp_nal=0x7fffffffd468, pi_nal=0x7fffffffd464, pic_in=0x7fffffffd470, 
    pic_out=0x7fffffffd4c0)
    at /tmp/build/src/libx265/source/encoder/api.cpp:105
        encoder = 0x66bf30
        nalunits = {0x0, 0x0, 0x0, 0x0, 0x0}
        numEncoded = 119
#3  0x00007ffff67a558f in ?? ()
   from /home/stefan/Dokumente/ffmpeg-git/lib/libavcodec.so.55
No symbol table info available.
#4  0x00007ffff6906672 in avcodec_encode_video2 ()
   from /home/stefan/Dokumente/ffmpeg-git/lib/libavcodec.so.55
No symbol table info available.
#5  0x000000000041e95e in ?? ()
No symbol table info available.
#6  0x0000000000408117 in ?? ()
No symbol table info available.
#7  0x00007ffff4d75de5 in __libc_start_main (main=0x406ec0, argc=12, 
    ubp_av=0x7fffffffdea8, init=<optimized out>, fini=<optimized out>, 
    rtld_fini=<optimized out>, stack_end=0x7fffffffde98) at libc-start.c:260
        result = <optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {0, -7112016030735285240, 
                4234400, 140737488346784, 0, 0, 7112016031736120328, 
                7111996038656410632}, mask_was_saved = 0}}, priv = {pad = {
              0x0, 0x0, 0x4244c0, 0x7fffffffdea8}, data = {prev = 0x0, 
              cleanup = 0x0, canceltype = 4342976}}}
        not_first_call = <optimized out>
#8  0x0000000000409cc9 in ?? ()
No symbol table info available.

```