avconv silently fails when input file count is over 50,000

Code:

    EMail=""
    SourceFolder="/home/astump/Desktop/var/www/Get/Cams/Archive/"
    UnpackFolder="/dev/shm/mp4tmp"   I am stepping through each process to  show where it fails:

    mkdir -p $UnpackFolder
    # Works
    unzip  -j $SourceFolder/"*.zip" -d $UnpackFolder
    # 719 archives were successfully processed. Works - had to change  /dev/shm to 12 GB in /etc/fstab
    CamImgQty=$(ls -l  $UnpackFolder/*.jpeg | wc -l)
    # Retus 57623
    CamSizeSum=$(du  -c $UnpackFolder/*.jpeg | sed -n "$s/\t.*//p")
    # Retus 8565616
    bash /dev/shm/Sequence.sh $UnpackFolder/ jpeg
    # This script  renames all files to avconv's %05d format. File count remains 57623,  size remains 8565616.
    ls /dev/shm/mp4tmp/00*
    # says display all 999  possibilities. It works.
    avconv -threads 8 -framerate 24 -i  $UnpackFolder/%05d.jpeg -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" -vcodec  libx264 -pix_fmt yuv420p /var/www/Get/Cams/MP4/$(date -d "yesterday  12:00" +'%y%m%d').mp4
    # Fails.  Here is what avconv retus - does  not help at all!

ffmpeg version 2.8.6-1ubuntu2 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.3.1 (Ubuntu 5.3.1-11ubuntu1) 20160311
  configuration: --prefix=/usr --extra-version=1ubuntu2 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
[mjpeg @ 0x224e8a0] Changeing bps to 8
Input #0, image2, from '/dev/shm/mp4tmp/%05d.jpeg':
  Duration: 00:40:00.96, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: mjpeg, yuvj422p(pc, bt470bg/unknown/unknown), 1152x1006 [SAR 1:1 DAR 576:503], 24 fps, 24 tbr, 24 tbn, 24 tbc
[swscaler @ 0x22751e0] deprecated pixel format used, make sure you did set range correctly
[libx264 @ 0x225d320] using SAR=1/1
[libx264 @ 0x225d320] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x225d320] profile High, level 3.2
[libx264 @ 0x225d320] 264 - core 148 r2643 5c65704 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=24 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to '/var/www/Get/Cams/MP4/160513.mp4':
  Metadata:
    encoder         : Lavf56.40.101
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1152x1006 [SAR 1:1 DAR 576:503], q=-1--1, 24 fps, 12288 tbn, 24 tbc
    Metadata:
      encoder         : Lavc56.60.100 libx264
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
Press [q] to stop, [?] for help
frame=   44 fps=0.0 q=-1.0 Lsize=     118kB time=00:00:01.75 bitrate= 551.1kbits/s    
video:117kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.982486%
[libx264 @ 0x225d320] frame I:1     Avg QP:20.90  size: 24312
[libx264 @ 0x225d320] frame P:35    Avg QP:21.33  size:  2330
[libx264 @ 0x225d320] frame B:8     Avg QP:21.33  size:  1605
[libx264 @ 0x225d320] consecutive B-frames: 63.6% 36.4%  0.0%  0.0%
[libx264 @ 0x225d320] mb I  I16..4: 19.7% 72.6%  7.7%
[libx264 @ 0x225d320] mb P  I16..4:  1.4%  5.1%  0.1%  P16..4: 11.2%  0.9%  0.8%  0.0%  0.0%    skip:80.6%
[libx264 @ 0x225d320] mb B  I16..4:  0.3%  0.3%  0.0%  B16..8: 11.1%  0.5%  0.1%  direct: 2.2%  skip:85.5%  L0:50.0% L1:49.5% BI: 0.6%
[libx264 @ 0x225d320] 8x8 transform intra:76.1% inter:92.7%
[libx264 @ 0x225d320] coded y,uvDC,uvAC intra: 15.6% 15.7% 1.7% inter: 2.3% 2.8% 0.1%
[libx264 @ 0x225d320] i16 v,h,dc,p: 57% 25%  6% 11%
[libx264 @ 0x225d320] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 24%  6% 64%  1%  1%  1%  1%  1%  1%
[libx264 @ 0x225d320] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 32% 24% 15%  4%  5%  5%  5%  4%  5%
[libx264 @ 0x225d320] i8c dc,h,v,p: 83% 11%  6%  0%
[libx264 @ 0x225d320] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x225d320] ref P L0: 53.3%  4.0% 27.5% 15.2%
[libx264 @ 0x225d320] ref B L0: 47.7% 52.3%
[libx264 @ 0x225d320] kb/s:517.97