Slashdot Mirror


Software to Buffer and Delay Audio Playback?

NaDrew asks: "Fox has seen fit to use two of its worst broadcasters (Joe Buck and the horrid Tim McCarver) for the upcoming World Series. I'd love to just turn down the TV and listen to the Giants' regular broadcast team (Duane Kuiper, Mike Krukow, Jon Miller) on my local Giants affiliate radio station, but as a DirecTV user this doesn't work. Why? Think about it: The radio signal traverses the 20-odd miles from Sutro Tower to my home in Palo Alto in a fraction of a second, but the video signal goes from KTVU's broadcast center in Oakland via satellite to DirecTV's operations center in Boulder, then via satellite again to my home--22,500 miles x 4 bounces equals almost 100,000 miles. Coupled with the MPEG processing done at DirecTV's operations center, this adds up to a delay of about six seconds. What I would like to do is buffer the audio from my radio for the appropriate amount of time and then play it back in sync with the video. Ideally I'd like a software solution that will run under Win32. A Google search yielded some specialized hardware solutions but nothing for my purpose. Ideas, pointers, even 'you idiot it's right here' flames are welcome. Thanks!"

8 of 86 comments (clear)

  1. Radio Delay by yasth · · Score: 5, Interesting

    Actually I am suprised that you aren't hit by a seven seccond radio delay. A simple way would be to write the data to disc, and use annother program to follow behind it. I.e. use some program to record the stream, and then 6 secconds later set winamp on the still recording stream, that should work, but no promises.

    --
    I'd do something interesting, but my server can't handle a slashdotting.
  2. Hmm, six seconds eh by gowen · · Score: 5, Funny

    Put your speaker about 1.167 miles away and turn them up *really* loud...

    --
    Athletic Scholarships to universities make as much sense as academic scholarships to sports teams.
  3. Multi-purpose audio tool by fingal · · Score: 5, Informative

    Why not download PD from here and have a play around. Creating a delay between the audio inputs and outputs is very easy...

    --

    The only Good System is a Sound System

  4. DMCA Violation by Anonymous Coward · · Score: 5, Funny

    Somebody Arrest this person.

    The modulation of an analog audio signal over a high frequency carrier wave is an "effective" copy control mechanism.

    By turning up your speakers really loud so that anybody can hear the broadcast is a circumvention technology that is not only illegal to implement under the DMCA but is also illegal to tell anybody else how to implement it.

    You sir are an INTELLECTUAL PROPERTY THIEF and are no better than the cranked up dope head that steals the purse of the poor widowed pensioner to pay for his next hit.

  5. Hardware solution for this by Geek+Boy · · Score: 5, Funny



    Get a spool of about 1,800,000 km of wire and use it to connect your speakers to the radio with carefully placed signal boosters/repeaters.
    YMMV

  6. Got a TiVo? by cybermage · · Score: 4, Interesting

    If you have, or can get, a TiVo that is seperate from your DirecTV receiver, you can try the following:

    1. Run the DirecTV Video straight to the tube.
    2. Connect the Audio from your Radio Tuner to the Audio In on the TiVo.
    3. Watch the DirctTV feed and listen to the TiVo feed.
    4. Pause/Fast Forward the TiVo until the audio is in sync with what you're seeing.

    To make sure the TiVo doesn't decide to change channels or anything, you might program it to record something as long as the game (like the game.)

  7. MPEG doesn't contribute to delay by MrResistor · · Score: 4, Informative

    All professional TV broadcasters have equipment that does MPEG processing in realtime (I'm one of the techs that fixes it when it breaks). Yeah, I guess maybe it could contribute a few ms of delay, but nothing you couldn't compensate for with the delay setting in a good reciever, and it is still probably less than the delay introduced by retransmitting, which still doesn't account for the 13-15s your talking about (6s + typical 7-8s delay on live radio).

    It's much more likely that KTVU has a playback delay set on their video server, mainly for the same reason that radio has one: bleeping out profanity before it hits the air.

    DirecTV certainly has a playback delay of at least 4s, which gives their automation system (which I also service) time to switch to an alternate stream if something goes wrong with the current one.

    Anyway, my point is your placing blame on the wrong parts of the process. That doesn't help with your case, of course. But my suggestion is to do exactly what the broadcasters are doing (except a lot cheaper):

    Run sound from your reciever to the line in on your soundcard. Record that with any sound recording program (the default Windows Sound Recorder will work just fine). Have a player up with the record target file ready to play, and start playback manually when you think the time is right.

    I haven't tried this so it might not work if Windows locks the record file during recording, but essentially that's exactly how it's being done on the video servers the broadcasters are using. I'm sure there's a better way to do this in Linux, but I haven't got around to playing with any of the Linux media tools yet.

    --
    Under capitalism man exploits man. Under communism it's the other way around.
  8. AudioMulch might just do the trick by i_am_nitrogen · · Score: 4, Informative

    I don't know if it's still around, but there was at one point a program called Audiomulch that worked kinda like a modular synthesizer setup. It has input and output modules, and a delay module, so you can just hook the audio out from the radio to your sound card, and connect the delay in-line between the input and output.