Input #0, concat, from 'test641464572510.9746237.txt':
  Duration: N/A, start: 0.000000, bitrate: 12 kb/s
    Stream #0:0(und): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuv444p, 74x57, 12 kb/s, 2 fps, 2 tbr, 16384 tbn, 4 tbc
    Metadata:
      handler_name    : VideoHandler
Output #0, mp4, to 'test64/main.mp4':
  Metadata:
    encoder         : Lavf57.25.100
    Stream #0:0(und): Video: h264 ([33][0][0][0] / 0x0021), yuv444p, 74x57, q=2-31, 12 kb/s, 2 fps, 2 tbr, 16384 tbn, 16384 tbc
    Metadata:
      handler_name    : VideoHandler
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
test641464572510.9746237.txt: Invalid argument
frame=   42 fps=0.0 q=-1.0 Lsize=      33kB time=00:00:20.50 bitrate=  13.0kbits/s speed=2.45e+04x
video:31kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 3.391250%