[gst-devel] audio playback shift in time

franchan francis.meyvis at gmail.com
Thu Sep 10 07:47:42 CEST 2009

Hello gstreamer developers,

Nobody knows an answer to my earlier question?

On Fri, Sep 4, 2009 at 5:23 PM, franchan <francis.meyvis at gmail.com> wrote:
> Hello,
> I have a custom mpegts demux. It gets data through the appsrc.
> Into the appsrc I push the mpegts coming from an UDP socket.
> This allows to do changing from UDP socket (other mpegts stream).
> When this happens I change the playbin2 first from playing to ready,
> Then back to playing again.
> The mpegts demux, when it sees the state change,
> removes its pads and waits for the new PAT/PMT information.
> When the mpegts sees the new PAT PMT, it recreates the new pads.
> Before the mpegts plugin sends out the PES data,
> I first send a flush-start, flush-stop and the new_segment event downstream.
> with the start and position time corresponding to the first PTS
> detected in the new mpegts data.
> For the first socket, when starting playback, all works fine: audio
> and video are in sync.
> When switching the socket the video starts playing fine after 1 to 2 seconds.
> However the audio behaves odd: its playback is delayed
> by the amount of time socket 1 has been playing.
> I verified the PTS timestamps on the input (in mpegts demux) and
> the output (audio/video decoders). These all seem fine;
> audio/video data is alternately push forward into the sinks.
> Still the alsa sink (or something else after the audio decoder)
> introduces this strange delay.
> Can somebody tell me what is going on and how to remove this delay for audio
> and still having the video play back as well?

(sorry I forgot to include my question again ...)


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