<p>There isn't support for taking the closed caption data from SDI and embedding it in the video stream. That's why it doesn't work.</p>

CC BY-SA 3.0
2012-12-19T02:40:48.073Z
Can you include a reference that supports your answer?
JoshP
CC BY-SA 3.0
2012-12-21T01:50:43.703Z
Well I wrote support for adding user data such as captions in x264 a long time ago and VLC doesn't use this API.
Kieran Kunhya
CC BY-SA 3.0
2012-12-19T00:50:55.003Z
2012-12-19T00:50:55.003Z
Kieran Kunhya
<p>I want to be able to stream live TV but also include the closed captions.  My workflow is to use a Blackmagic Designs Decklink card (video source is SDI) and use VLC to capture and transcode the video, then send that to a Wowza server to be packetized for HTTP streaming.  I have this working for Video, but I cannot figure out how to get the closed captions to appear in my player.  I am using a VLC Player, Quicktime, Flowplayer on a web page, iPad, and iPhone to view the streams, none of them show the closed captioning in the source video.  The closed captions are both 608 and 708.  I have spent the last 3 days reading everything I can about vlc and closed captions, wowza and closed captions, and x264 and closed captions, vbi, teltext, and even subtitles, but I am no where closer than when I started.  I sincerely that someone here will be able to help me.</p>

<p>I am using a core i7 with 4GB ram, runign ubuntu 10.04 64bit.  I compiled vlc with the following:</p>

<pre><code>./configure  '--enable-xvideo' '--enable-sdl' '--enable-avcodec' '--enable-avformat' '--enable-swscale' '--enable-mad' '--enable-a52' '--enable-libmpeg2' '--enable-dvdnav' '--enable-faad' '--enable-vorbis' '--enable-ogg' '--enable-theora' '--enable-mkv' '--enable-flac' '--enable-caca' '--enable-alsa' '--enable-qt4' '--enable-ncurses' '--enable-realrtsp' '--enable-twolame' '--enable-real' '--enable-x264' '--with-decklink-sdk=/home/bimls/bmd/Blackmagic_Decklink_SDK_9.6.4/Linux' '--enable-zvbi'
</code></pre>

<p>I use the following to capture and stream the live video:</p>

<pre><code>cvlc decklink:// --decklink-card-index="0" --decklink-mode="ntsc" --rtsp-timeout 0 --sout='#transcode{venc=x264{subme=1, ref=1, bframes=16, b-adapt=1, bpyramid=none, weightp=0 }, vcodec=h264, vb=1300, acodec=mp4a, ab=96, threads=4}:rtp{dst=127.0.0.1:8888,mux=ts}'' --vbi-page=100 --no-vbi-opaque --vbi-position=0
</code></pre>

<p>Some of the question I have are:</p>

<ul>
<li>Is this the proper way to get the closed captions to appear? if not please what am I doing wrong? </li>
<li>How does one
know what vbi-page to look for as the range seems to be "--vbi-page integer [-2147483648 .. 2147483647]>" </li>
<li>Does transcoding destroy
closed caption data?</li>
</ul>

<p>So, Please any help will be greatly appreciated! Thank you!</p>

<streaming><transcoding>
How to get closed captions to appear on a live stream
user1612292
# How to get closed captions to appear on a live stream

(Asked by: username_0 on 2012-12-14)

I want to be able to stream live TV but also include the closed captions.  My workflow is to use a Blackmagic Designs Decklink card (video source is SDI) and use VLC to capture and transcode the video, then send that to a Wowza server to be packetized for HTTP streaming.  I have this working for Video, but I cannot figure out how to get the closed captions to appear in my player.  I am using a VLC Player, Quicktime, Flowplayer on a web page, iPad, and iPhone to view the streams, none of them show the closed captioning in the source video.  The closed captions are both 608 and 708.  I have spent the last 3 days reading everything I can about vlc and closed captions, wowza and closed captions, and x264 and closed captions, vbi, teltext, and even subtitles, but I am no where closer than when I started.  I sincerely that someone here will be able to help me.
I am using a core i7 with 4GB ram, runign ubuntu 10.04 64bit.  I compiled vlc with the following:
./configure  '--enable-xvideo' '--enable-sdl' '--enable-avcodec' '--enable-avformat' '--enable-swscale' '--enable-mad' '--enable-a52' '--enable-libmpeg2' '--enable-dvdnav' '--enable-faad' '--enable-vorbis' '--enable-ogg' '--enable-theora' '--enable-mkv' '--enable-flac' '--enable-caca' '--enable-alsa' '--enable-qt4' '--enable-ncurses' '--enable-realrtsp' '--enable-twolame' '--enable-real' '--enable-x264' '--with-decklink-sdk=/home/bimls/bmd/Blackmagic_Decklink_SDK_9.6.4/Linux' '--enable-zvbi'

I use the following to capture and stream the live video:
cvlc decklink:// --decklink-card-index="0" --decklink-mode="ntsc" --rtsp-timeout 0 --sout='#transcode{venc=x264{subme=1, ref=1, bframes=16, b-adapt=1, bpyramid=none, weightp=0 }, vcodec=h264, vb=1300, acodec=mp4a, ab=96, threads=4}:rtp{dst=127.0.0.1:8888,mux=ts}'' --vbi-page=100 --no-vbi-opaque --vbi-position=0

Some of the question I have are:

Is this the proper way to get the closed captions to appear? if not please what am I doing wrong? 
How does one
know what vbi-page to look for as the range seems to be "--vbi-page integer [-2147483648 .. 2147483647]>" 
Does transcoding destroy
closed caption data?

So, Please any help will be greatly appreciated! Thank you!

**Tags:** streaming, transcoding


---

## 1 answers

### Answer by username_1 on 2012-12-19. Score: 1

There isn't support for taking the closed caption data from SDI and embedding it in the video stream. That's why it doesn't work.

> **Comments:**
> **username_2**: Can you include a reference that supports your answer?  
> **username_1**: Well I wrote support for adding user data such as captions in x264 a long time ago and VLC doesn't use this API.  

---

