Input #0, x11grab, from ':0.0':
  Duration: N/A, start: 1518987964.931243, bitrate: N/A
    Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 640x480, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
Input #1, lavfi, from 'anullsrc':
  Duration: N/A, start: 0.000000, bitrate: 705 kb/s
    Stream #1:0: Audio: pcm_u8, 44100 Hz, stereo, u8, 705 kb/s
[h264_omx @ 0x72f530] libOMX_Core.so not found
[h264_omx @ 0x72f530] libOmxCore.so not found
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (h264_omx))
  Stream #1:0 -> #0:1 (pcm_u8 (native) -> aac (native))
Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height