<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta name="Generator" content="Microsoft Word 14 (filtered medium)"> <style></style> </head> <body lang="EN-GB" link="blue" vlink="purple"> <div class="WordSection1"> Hi,<o:p></o:p> <o:p> </o:p> Yes indeed I only do buffer->get_pts() after demuxing.<o:p></o:p> Correctly assigning material to events is a good example. If I get an event saying “Foobar” is on at 9pm how can I determine from the (demuxed) TS when 9pm is in terms of the buffer mini objects I’m processing?<o:p></o:p> For testing I wish to playback a TS from a file as fast as possible rather than real-time. So all the time information must be in the TS somewhere. My guess is to use the TDT to get an absolute time-stamp and relate either the gstreamer PTS or the mpeg PCR & PTS to it somehow. <o:p></o:p> <o:p> </o:p> For a little more background I’m effectively monitoring live TS streams for events of interest detected by processing the audio (or video). I need to determine the absolute time of these events to associate them with events on other streams. The same code should work on a recorded TS as well. <o:p></o:p> <o:p> </o:p> At the moment it looks like I have to use the system clock for a live stream and provide a start time for a recorded TS. It seems like there ought to be an alternative way as the TS should know when it was recorded if, for example, it includes a TDT.<o:p></o:p> <o:p> </o:p> Regards,<o:p></o:p> <o:p> </o:p> Bruce.<o:p></o:p> <o:p> </o:p> <o:p> </o:p> <div> <div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm"> From: gstreamer-devel [mailto:gstreamer-devel-bounces@lists.freedesktop.org] On Behalf Of krzysztof.konopko@konagma.eu Sent: 09 May 2018 10:06 To: Discussion of the development of and with GStreamer Subject: Re: MPEG TS PCR and PTS<o:p></o:p> </div> </div> <o:p> </o:p> <div> Hi,<o:p></o:p> </div> <div> <o:p></o:p> </div> <div> To my understanding, `buffer->get_pts()` makes little sense in case of MPEG-TS as each GStreamer buffer will typically hold a number of TS packets which in turn can be part of different PES packets and elementary streams and relate to different access units (frames). So I do not find it particularly useful to indicate with GStreamer PTS when to "present" such ambiguous chunk of stream before demuxing it.<o:p></o:p> </div> <div> <o:p></o:p> </div> <div> Also to my understanding information like TOT/TDT is more useful when presenting programme events (EIT) for example in a guide and to synchronise intended start date and time of the events with the local time (for presentation or recording purposes). I can't see how it could be useful to relate it to the actual media time where it's not really useful to care about absolute values especially when timestamps can wrap.<o:p></o:p> </div> <div> <o:p></o:p> </div> <div> Kris<o:p></o:p> </div> <div> <o:p></o:p> </div> <div> On Fri, 2018-05-04 at 07:13 +0000, Adams, Bruce (KMLWG) wrote:<o:p></o:p> </div> <blockquote style="border:none;border-left:solid #1010FF 1.5pt;padding:0cm 0cm 0cm 4.0pt;margin-left:3.75pt;margin-top:5.0pt;margin-bottom:5.0pt"> <div> Hi,<o:p></o:p> I am trying to work out how to get absolute time-stamps from an incoming MPEG transport stream.<o:p></o:p> The basics seem to be that we get a presentation time-stamp via buffer->get_pts(). This is relative to the program clock reference PCR which is dictated by one of the elementary streams – typically the video. How do I get that base time out of gstreamer?<o:p></o:p> I note that if I use a tsparse element it can decode TOT and TDT sections for DVB inputs. However, I also notice that one of my inputs is a TSIP input which does not include these sections.<o:p></o:p> How can I tell if an absolute time reference is available and when it is what is the epoch? Is it the standard unix epoch 1970-01-01T00:00:00Z?<o:p></o:p> <o:p></o:p> Regards,<o:p></o:p> <o:p></o:p> Bruce.<o:p></o:p> </div> <a href="http://www.kantar.com/disclaimer.html">Kantar Disclaimer</a> <o:p></o:p> <pre>_______________________________________________<o:p></o:p></pre> <pre>gstreamer-devel mailing list<o:p></o:p></pre> <pre><a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a><o:p></o:p></pre> <pre><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.freedesktop.org_mailman_listinfo_gstreamer-2Ddevel&d=DwMFaQ&c=zdK58V2JKULZdB8nuBRpog&r=8VGOHR75e9VH5R2ry5VaPdkvUX6ll39esPT0cMlxEuA&m=Ap5BFPSzFHbHfSn4C4KVzBqfLpMpz_IPJGBz3wlvlk0&s=js5xzDojZ1uwum3WCMLmCBFm-6tYehT8F6YUiEZstZI&e=">https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a><o:p></o:p></pre> </blockquote> <div> <o:p></o:p> </div> </div> </body> </html>