Demuxer png_pipe [piped png sequence]:
png demuxer AVOptions:
  -frame_size        <int>        .D....... force frame size in bytes (from 0 to INT_MAX) (default 0)
  -framerate         <video_rate> .D....... set the video framerate (default "25")
  -pixel_format      <string>     .D....... set video pixel format
  -video_size        <image_size> .D....... set video size
  -loop              <boolean>    .D....... force loop over input file sequence (default false)


