[FFmpeg-devel] [PATCH 1/3] closed caption decoder: accept and decode a new codec type of 'raw 608 byte pairs'

Roger Pack rogerdpack2 at gmail.com
Fri May 1 06:59:11 EEST 2020


On Thu, Apr 30, 2020 at 4:30 AM Kieran Kunhya <kierank at obe.tv> wrote:
>
> On Thu, 30 Apr 2020 at 07:22, Roger Pack <rogerdpack2 at gmail.com> wrote:
>
> > > > c9153590e5f167e41910d867639eb887164e28d2
> > 0001-closed-caption-decoder-accept-and-decode-a-new-codec.patch
> > > > From bf29fe5330e83e37cf064b18918185c6b00d9b9f Mon Sep 17 00:00:00 2001
> > > > From: rogerdpack <rogerpack2005 at gmail.com>
> > > > Date: Tue, 28 Apr 2020 05:15:15 +0000
> > > > Subject: [PATCH 1/3] closed caption decoder: accept and decode a new
> > codec
> > > >  type of 'raw 608 byte pairs'
> >
>
> How does this content exist? Are you defining your own file format with the
> byte pairs?

It's transmitted as "raw byte pairs" by analog TV broadcast in the US.
https://en.wikipedia.org/wiki/EIA-608 has  details.

I believe it transmits  one closed caption character (or control code)
per frame (basically a single byte pair on "line 21") so it can do 30
closed caption chars/second.  Anyway that's where it's originating
from.  Good question :)

Thanks!


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