ffmpeg amerge wo video

ffmpeg -i bbb.mov  -filter_complex "amovie=loop1.aac:loop=0[loop],[0:a][loop]amerge=inputs=2,pan=stereo|c0<c0+c2|c1<c1+c3[aout]"  -map [aout] -shortest -y  atest6.mp4
ffmpeg version 2.7.2 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.8.3 (GCC) 20140911 (Red Hat 4.8.3-9)
  configuration: --prefix=/tools --extra-cflags=-I/tools/include --extra-ldflags=-L/tools/lib --pkg-config-flags=--static --enable-gpl --enable-nonfree --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libvpx --enable-libx264 --enable-libx265
  libavutil      54. 27.100 / 54. 27.100
  libavcodec     56. 41.100 / 56. 41.100
  libavformat    56. 36.100 / 56. 36.100
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 16.101 /  5. 16.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.100 /  1.  2.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'bbb.mov':
  Metadata:
    major_brand     : qt  
    minor_version   : 512
    compatible_brands: qt  
    encoder         : Lavf56.36.100
  Duration: 00:09:56.52, start: 0.042667, bitrate: 5291 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1280x720, 5146 kb/s, 24 fps, 24 tbr, 19200 tbn, 38400 tbc (default)
    Metadata:
      handler_name    : DataHandler
      encoder         : H.264
      timecode        : 00:00:00:00
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 139 kb/s (default)
    Metadata:
      handler_name    : DataHandler
    Stream #0:2(eng): Data: none (tmcd / 0x64636D74)
    Metadata:
      handler_name    : DataHandler
      timecode        : 00:00:00:00
[aac @ 0x2fee100] Estimating duration from bitrate, this may be inaccurate
[Parsed_amerge_1 @ 0x30400c0] No channel layout for input 1
[Parsed_amerge_1 @ 0x30400c0] Input channel layouts overlap: output layout will be determined by the number of distinct input channels
Output #0, mp4, to 'atest6.mp4':
  Metadata:
    major_brand     : qt  
    minor_version   : 512
    compatible_brands: qt  
    encoder         : Lavf56.36.100
    Stream #0:0: Audio: aac (libfdk_aac) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, s16, 139 kb/s (default)
    Metadata:
      encoder         : Lavc56.41.100 libfdk_aac
Stream mapping:
  Stream #0:1 (aac) -> amerge:in0
  pan -> Stream #0:0 (libfdk_aac)
Press [q] to stop, [?] for help
size=   10279kB time=00:09:56.52 bitrate= 141.2kbits/s    
video:0kB audio:10169kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.082452%