ffmpeg framemd5 format explanation
According to the framemd5 muxer documentation:


  This muxer computes and prints the MD5 hash for each audio and video
  packet. By default audio frames are converted to signed 16-bit raw
  audio and video frames to raw video before computing the hash.
  
  The output of the muxer consists of a line for each audio and video
  packet of the form:

stream_index, packet_dts, packet_pts, packet_duration, packet_size, MD5

  
  MD5 is a hexadecimal number representing the computed MD5 hash for the
  packet.


If you want to omit a particular stream or stream type use the -map option. This example will only process the video stream while ignoring audio:

ffmpeg -i input -map 0:v:0 -f framemd5 -