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Thread: IOS Captions Doubling-Up

  1. #1

    Default IOS Captions Doubling-Up

    Hello -

    I have noticed that when media is recorded sever-side that has the 608-style captions in it (that is, in the video track, as implemented by the Wowza-supplied code to accomplish the live stream captions in IOS), if one wishes to "override" that with a sidecar file in the URL for subsequent OnDemand playback, one receives BOTH captions - the sidecar and the embedded 608-style.

    Is there a method by which either (i) the sidecar can override the embedded or (ii) the 608 captions may be selected to not write to disk when recording server-side?

    Kind Regards

    --dan

  2. #2
    Join Date
    May 2011
    Posts
    456

    Default

    We do not currently support removing CEA-608 captions from a VOD asset if the captions are present. We have passed on this feature request to our product management team.

    -Lisa

  3. #3

    Default

    Quote Originally Posted by lisa_w View Post
    We do not currently support removing CEA-608 captions from a VOD asset if the captions are present. We have passed on this feature request to our product management team.

    -Lisa
    Lisa

    Thanks for the reply! Okay so that's half of it - will be a nice feature. For the other part, is there a method by which the 608 captions can be "not" recorded server side? Alternatively could they be injected after the recorder instead of before? Mite be a quick stopgap...?

    Thanks again!

    --dan

  4. #4
    Join Date
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    Based on other posts, you are using LiveStreamRecord so there is actually a parameter to turn data recording off,
    though it is not available in the UI, it can be triggered when recording using the http provider:

    example:
    http://[wowza-address]:8086/livestreamrecord?app=live&streamname=myStream&action=startRecording&recorddata=false
    All available url params are in this article http://www.wowza.com/forums/content....#userinterface
    Under the heading "Recording live streams using URL queries"

    See if that helps at all.

    Daren
    Last edited by daren_j; 03-19-2013 at 12:15 PM.

  5. #5

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    Quote Originally Posted by daren_j View Post
    Based on other posts, you are using LiveStreamRecord so there is actually a parameter to turn data recording off,
    though it is not available in the UI, it can be triggered when recording using the http provider:

    example:
    http://[wowza-address]:8086/livestre...corddata=false

    All available url params are in this article http://www.wowza.com/forums/content....#userinterface
    Under the heading "Recording live streams using URL queries"

    See if that helps at all.

    Daren
    Daren:

    Thanks for your reply - however, this will turn off Data Recording for all the streams. Since the 608 captions are baked into the video track and there are a sum total of zero tools to remove them, it's difficult to go this route, as you might imagine.

    If I turn off the recording of all data, I would lose (assuming I get it to work; see other thread) the data track in the MP4 as well.

    To illustrate why this is a problem, consider the following scenario:
    1. Media is streamed Live with Video and Audio.
    2. Closed captions are injected as above.
    3. Closed Captioning is enabled, for Flash as well as IOS (using the Wowza libs)
    4. Files are recorded server-side.

    Now we have file(s) with (ostensibly) _both_ 608 captions in the video track, AND a data track with those same captions. It's trivial to remove that data track and generate an srt (or some other file) from it, if so desired, but that darn 608 track is still there - and there seems to be no good way to get it removed.

    If the captioning is perfect every time, then this is no issue. However, if one wishes to re-caption something, or if there's junk data in the 608 portion, there's no way to show something else in the IOS presentation, even if you try and override with a sidecar file - you get doubled-up captions if a sidecar is used.

    Make sense?

    The crux of the matter here is that the 608 data that is sent with Live stream gets recorded to the file. If that were a toggle somewhere, all of this could be eliminated, and we could use available tools for dealing with the lifecycle of the media.

    Thanks so much for your help here - anything that I've missed, please feel free to point out!

    --dan

  6. #6
    Join Date
    Jun 2011
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    So is this the actual workflow (just want to confirm)?

    1. Media is streamed Live with Video and Audio.
    2. Closed captions are injected as above.
    3. Closed Captioning is enabled, for Flash as well as IOS (using the Wowza libs)
    4. Files are recorded server-side.

    Does the incoming stream in in (1.) above already have the CEA-608 at all ?

    Or you are you (2.) only adding OnTextData and having that converted to CEA-608, as the ModuleClosedCaptionLive provides?

    Unfortunately we don't have a way to remove the CEA-608 from the stream before recording, so actually the above property provided would only exclude text tracks from the recording and would still keep the muxed data.

    Daren

  7. #7

    Default

    Quote Originally Posted by daren_j View Post
    So is this the actual workflow (just want to confirm)?

    1. Media is streamed Live with Video and Audio.
    2. Closed captions are injected as above.
    3. Closed Captioning is enabled, for Flash as well as IOS (using the Wowza libs)
    4. Files are recorded server-side.

    Does the incoming stream in in (1.) above already have the CEA-608 at all ?

    Or you are you (2.) only adding OnTextData and having that converted to CEA-608, as the ModuleClosedCaptionLive provides?

    Unfortunately we don't have a way to remove the CEA-608 from the stream before recording, so actually the above property provided would only exclude text tracks from the recording and would still keep the muxed data.

    Daren
    Daren:

    First, you guys are great - thanks so much for the wonderful support here. Any offer of help in this area is very welcomed. Captioning is so new and with the impending legal issues we're all scrambling as fast as we can. I'm thankful for your work so far and look forward to getting something going.

    Okay, so on to your question - no, the 608 is not present in the Live feed. But, when it's recorded, it _is_ in the resultant OnDemand file - and there's no way to tell Wowza "do not record the 608 captions, but show them in the Live stream".

    Also, I understand what you say that the text tracks are excluded but the 608 is still there, so we are _really_ stuck with it, at least in the IOS world. I'm working in another thread relative to not having the text tracks being captured in the server-side record files, so we're going thru this one step at a time - right now it seems I have the worst of all worlds, but we'll get it sorted...

    We'll stick a pin in this one for now, and I'll be sure to come back when I have more info that may be beneficial for others. I hope others will do the same (or at least point out where I'm crazy!).

    Anyhow, thanks again for the good work.

    --dan

  8. #8
    Join Date
    Jun 2011
    Posts
    1,037

    Default

    We did a few updates to make this better by adding the property closedCaptionLiveRemoveExistingCEA608
    To use this you'll need the latest Wowza Media Server build:
    http://www.wowza.com/forums/content....lopment-Builds

    And then re-download the latest ClosedCaptionLive.zip package:
    http://www.wowza.com/forums/content.php?447

    Additional info about the property is in the included README.html file.

    Daren

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