title: Parsing NAL units using FFMPEG
body: <p>I am new to MPEG-4 and taking baby steps to learn it. I am using FFMPEG as reference.</p>
  
  <ol>
  <li><p>I understand that all mpeg-4 are encoded into NAL units and wrt to FFMPEG av_read_frame() function returns one NAL unit, Am I right? Is frame a NAL unit? (though it can be a combination of multiple NALs)</p></li>
  <li><p>I also saw that h264_parser.c implements a function called h264_parse which is calling parse_nal_units() inside, If i need to get NAL units how can I use this parse_nal_units from my main function?</p></li>
  <li><p>What is av_parse_Parse2() function do? does it return decoded NAL units?</p></li>
  <li><p>OR  FFMPEG has -vbsf h264_mp4toannexb switch to dump raw NAL units, Can somebody help me understand how I can use the same from my main function?</p></li>
  </ol>
  
  <p>Please help me out here...
  -ash5</p>