Closed Captions

Discussion in 'TiVo Home Media Features & TiVoToGo' started by bobfrank, Aug 30, 2011.

  1. bobfrank

    bobfrank Active Member

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    I need help in getting Tivo to show closed captions on videos uploaded from the computer.

    I have .mpg video files ripped from DVD (owned copies). Using VideoReDo or VLC I can play the files and turn closed captions on and off. So I know the captioning is still encoded into the mpg files.

    But, when I upload the files to my Tivo, either with Tivo Desktop or PyTivo I cannot turn on the closed captions on the Tivo.

    Is there a way to get Tivo to recognize the closed captions in the files?

    Thanks in advance.

    Bob
     
  2. dobbie1

    dobbie1 Member

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    I believe "Streambaby" will play the closed captions as it is streaming the files.
     
  3. txporter

    txporter One sec, almost done

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    The problem that you are having is that the captions that you are viewing from DVD rips seem to be somehow different than what the Tivo is expecting to see for captioning. I have had some success using T2SAMI to remux the captions into the mpg file correctly for Tivo. You will need to first extract the captions into another format (srt is usually the easiest to deal with) before you can do this. Using a program like CCextractor, you can accomplish this. I only tried this a few times as I saw some issues with timing. As far as I know though, T2SAMI is the only program that will remux the files correctly with captions for Tivos.

    Like dobbie1 said, if you can get the captions into a srt file, you can use streambaby to stream the file with captions.

    My wife and I always watch using captions so I have just gone to writing the captions right into the video (hardcoding). I just transcode my videos to H.264 now and hardcode the captions using x264.exe and avisynth scripts. Probably not what you were really wanting to hear.
     
  4. bobfrank

    bobfrank Active Member

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    I've already tried T2SAMI and found, like you did, that T2SAMI seems to create timing issues. So that makes it essentially unusable.

    I had already tried .srt files with StreamBaby. Unfortunately captions with StreamBaby are all or nothing. I wasn't able to turn them on or off as needed.

    Another problem with StreamBaby is that we boot into a separate partition when the Grandkids are here using the computer so StreamBaby isn't available all the time.

    Thanks for the suggestions. Sadly none of them help.

    Bob
     
  5. Dan203

    Dan203 Super Moderator Staff Member TCF Club

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    Bob can you upload a small sample (<100MB) of a file directly from a DVD that doesn't work, and then the same file processed with T2SAMI that does work (albeit off). I'd like to look at what exactly T2SAMI does to the captions to see if it's something we can incorporate into VideoReDo.

    Please use the FTP upload instructions on the VRD forum and make sure to send an email to support when you're done with the subject "Attn: Dan203 files for TiVo caption issue".

    Dan
     
  6. bobfrank

    bobfrank Active Member

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    I be happy to. I've deleted my previousT2SAMI tests, but I'll make another one later today.

    Bob
     
  7. jmemmott

    jmemmott New Member

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    Santa Cruz, CA
    That's the hard way to do it. Simpler to ask...

    T2Same was written for the Series 2. Series 2's only handled MPEG2 program streams and only understood EIA 608 and EIA 708 captions so T2Sami rewrote the program stream converting the incoming captions ( .srt, .sami, ... ) to a series of MPEG2 picture user data packets with 608 closed caption encoding and injected them into the frames in the correct order so that the Tivo would reconsturct them as standard broadcast closed captions. As you might imagine, it was a bit messy and subject to a number of constaints. The same approach would work with mpeg4 and transport streams but I never saw the point in doing the work. By that time, the two techniques that txporter discribes above were available and I felt they were simpler, faster and therefore better approaches to move forward with.
     
  8. Sep 1, 2011 #8 of 14
    bobfrank

    bobfrank Active Member

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    Dan,

    I've uploaded the files as you requested. They are in a folder called:

    Dan203FilesForTivoCaptionIssue

    An email has also been sent to support per your instructions above.

    If you can get this ability into VideoReDo I promise to name my next child after you. Of course at my age this is highly unlikely to happen so don't get your hopes up too much.

    Bob
     
  9. Sep 1, 2011 #9 of 14
    Dan203

    Dan203 Super Moderator Staff Member TCF Club

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    I'm not a caption expert, but don't DVDs use 608 captions stored as user data? If so then why wont a DVD retain it's captions when transferred directly to a TiVo? What's different?

    Dan
     
  10. jmemmott

    jmemmott New Member

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    They do but they are stored differently so the Tivo does not process them. On a DVD, the captions are all stored as a block at the beginning of the GOP. The DVD player then takes care of displaying them with correct timing. In broadcast video, the captions are spread across all of the picture frames, two characters per frame. Caption timing is derived from the frame timing so you have to pay attention to the frame types : I, P and B as well as the frame display time when you redistribute the captions from a DVD block format to the broadcast format...
     
  11. Dan203

    Dan203 Super Moderator Staff Member TCF Club

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    I'll have to talk to DanR about this but I bet there is a way we can handle this and make all CC output TiVo compatible.

    bob- I'm not sure which version of VRD you use, but if we do add this feature it will most likely only get added to TVSuite v4 w/H.264. Development for the other two versions is pretty much limited to critical bug fixes at this point.

    Dan
     
  12. bobfrank

    bobfrank Active Member

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    I've got them all. So adding this feature to v4 is fine with me.

    Boib
     
  13. txporter

    txporter One sec, almost done

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    This is interesting information. I always wondered why whenever captions had missing character it was always in multiples of 2. What do you mean that the captions are spread across all of the picture frames, two characters per frame?

    Surely that doesn't mean that "These closed captions are meant to be displayed all at once." would take 25 frames before all of that information is displayed?
     
  14. jmemmott

    jmemmott New Member

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    They can be displayed as they come in but remember the television frame rate is just under 30 frames per second so at two characters per frame that would be a maximum display rate of 60 characters per second. A little to fast to read in any sustained fashion. As the characters come in, they go into internal memory buffers. Characters can be allowed to build up in a buffer that is visible and displayed continuously - thus the illusion of typing on the screen with "scroll-on" captions. In other cases, the buffer can hidden or swapped with an offscreen buffer and the captions are accumulated for display all a once; called "pop-on" captions. In any case, in addition to the text itself, the stream contains control information for these and other operations to give the captioners control over what, how and where you see the captions.
     

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