On Thu January 31 2013 00:02:22 Devin Heitmueller wrote:
> Add a new possible value to the V4L2 API for embedded VBI data,
> which allows for embedding of CC and teletext data in the userdata
> section of the GOP. This allows for compatibility with applications
> such as VLC which already have code to read captions out of the
> userdata area for ATSC A/53 compliant streams.
>
> This will be used by the cx18 driver to embed closed captions for NTSC
> streams.
Looks good, but if possible a bibliography entry for the relevant standard(s)
would be helpful.
Regards,
Hans
>
> ---
> Documentation/DocBook/media/v4l/controls.xml | 4 ++++
> Documentation/DocBook/media/v4l/dev-sliced-vbi.xml | 9 +++++++++
> include/uapi/linux/v4l2-controls.h | 1 +
> 3 files changed, 14 insertions(+)
>
> diff --git a/Documentation/DocBook/media/v4l/controls.xml
> b/Documentation/DocBook/media/v4l/controls.xml
> index 9e8f854..4b41b32 100644
> --- a/Documentation/DocBook/media/v4l/controls.xml
> +++ b/Documentation/DocBook/media/v4l/controls.xml
> @@ -862,6 +862,10 @@ are:</entry>
> <entry>VBI in private packets, IVTV format (documented
> in the kernel sources in the file
> <filename>Documentation/video4linux/cx2341x/README.vbi</filename>)</entry>
> </row>
> + <row>
> +
> <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_USERDATA_GOP</constant> </entry>
> + <entry>VBI in user_data section of GOP for MPEG2 streams
> (to embed closed captions that comply with ATSC A/53)</entry>
> + </row>
> </tbody>
> </entrytbl>
> </row>
> diff --git a/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml
> b/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml
> index 548f8ea..d295252 100644
> --- a/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml
> +++ b/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml
> @@ -696,4 +696,13 @@ Sliced VBI services</link> for a description of the line
> payload.</entry>
> </table>
>
> </section>
> +
> + <section>
> + <title>MPEG Stream Embedded, Sliced VBI Data Format: USERDATA_GOP</title>
> + <para>The <link linkend="v4l2-mpeg-stream-vbi-fmt"><constant>
> +V4L2_MPEG_STREAM_VBI_FMT_USERDATA_GOP</constant></link> embedded sliced VBI
> +format injects EIA-608 closed captions or Teletext into the Userdata GOP
> area of the MPEG2 stream. This format allows for caption embedding which
> complies with the ATSC A/53 specification (the same format used for ATSC
> digital television streams in the United States).</para>
> + <para>This format is not as flexible as the IVTV format as it does not
> allow for embedding of arbitrary sliced VBI data. However it does have the
> advantage of being the same format used for ATSC digital television streams,
> meaning any application which can render captions for digital streams should
> be able to render captions for these streams as well with no additional code
> changes.</para>
> + </section>
> +
> </section>
> diff --git a/include/uapi/linux/v4l2-controls.h
> b/include/uapi/linux/v4l2-controls.h
> index 4dc0822..ad4901e 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -166,6 +166,7 @@ enum v4l2_mpeg_stream_type {
> enum v4l2_mpeg_stream_vbi_fmt {
> V4L2_MPEG_STREAM_VBI_FMT_NONE = 0, /* No VBI in the MPEG stream */
> V4L2_MPEG_STREAM_VBI_FMT_IVTV = 1, /* VBI in private packets, IVTV
> format */
> + V4L2_MPEG_STREAM_VBI_FMT_USERDATA_GOP = 2, /* Inject VBI into
> user_data GOP */
> };
>
> /* MPEG audio controls specific to multiplexed streams */
>
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
