Filter readeia608
  Read EIA-608 Closed Caption codes from input video and write them to frame metadata.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
readeia608 AVOptions:
  scan_min          <int>        ..FV..... set from which line to scan for codes (from 0 to INT_MAX) (default 0)
  scan_max          <int>        ..FV..... set to which line to scan for codes (from 0 to INT_MAX) (default 29)
  mac               <float>      ..FV..... set minimal acceptable amplitude change for sync codes detection (from 0.001 to 1) (default 0.2)
  spw               <float>      ..FV..... set ratio of width reserved for sync code detection (from 0.1 to 0.7) (default 0.27)
  mhd               <float>      ..FV..... set max peaks height difference for sync code detection (from 0 to 0.5) (default 0.1)
  mpd               <float>      ..FV..... set max peaks period difference for sync code detection (from 0 to 0.5) (default 0.1)
  msd               <float>      ..FV..... set first two max start code bits differences (from 0 to 0.5) (default 0.02)
  bhd               <float>      ..FV..... set min ratio of bits height compared to 3rd start code bit (from 0.01 to 1) (default 0.75)
  th_w              <float>      ..FV..... set white color threshold (from 0.1 to 1) (default 0.35)
  th_b              <float>      ..FV..... set black color threshold (from 0 to 0.5) (default 0.15)
  chp               <boolean>    ..FV..... check and apply parity bit (default false)
  lp                <boolean>    ..FV..... lowpass line prior to processing (default false)

This filter has support for timeline through the 'enable' option.

