[FFmpeg-devel] Add mpeg user_data CEA-608/708 extraction.

Daniel Kristjansson danielk
Sun Apr 11 21:17:02 CEST 2010

On Sun, 2010-04-11 at 14:20 -0400, Ronald S. Bultje wrote:
> Hi,
> On Sun, Apr 11, 2010 at 2:15 PM, Daniel Kristjansson
> <danielk at cuymedia.net> wrote:
> > This patch pulls CEA-608 and 708 data from the user data and puts it
> > in atsc_cc_buf buffer attached to each frame. The data passed in
> > atsc_cc_buf is CEA-708-D caption packets for both data encoded using
> > the ATSC user data and the SCTE-20 user data encodings. An example
> > of how to decode this for display is present in MythTV, ccextract,
> > etc.
> Shouldn't that go into a separate captions (=text) AVStream?

CEA-708/608 are not really text streams any more than MPEG-2 layer 2
is a text stream. CEA-708 especially, it specifies windows, fonts,
glyphs, colors, precise anchors and flow alignment anchor for the
specific frame that it is on. It could be put in another specialized
stream, but then the player would need additional layers of buffering
to remux this stream with the video stream to remarry each packet
with the video frame it belongs with so it can be parsed correctly.

-- Daniel

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