gstclock and absolute time

Tue Jun 26 09:49:58 PDT 2012

Hi all again,

Probably I found something interesting activating log for "rtpbin":

GST_DEBUG=rtpbin:5 gst-launch --gst-debug-no-color rtspsrc
location=rtsp://192.168.3.27/axis-media/media.amp?audio=0 latency=200
! rtph264depay ! ffdec_h264 ! ffmpegcolorspace ! shmframeserver
latency=200 ! ffmpegcolorspace ! fakesink

http://pastebin.com/ZqaN09MQ

it seems that rtpbin cannot read localtime....any clue? Is it a bug?

BR,

pz

2012/6/26 Pazzo Da Legare <pazzodalegare at gmail.com>:
> Dear Josh,
>
> I want just to add a bit of info. I'm trying to understand how to
> correlate data from signal "handle-sync"
> (http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-good-plugins/html/gst-plugins-good-plugins-gstrtpjitterbuffer.html#GstRtpJitterBuffer-handle-sync)
>  of GstRtpJitterBuffer and "stats" of rtpsession but I really don't
> understand what base-time is....
>
> This is what I get from GstRtpJitterBuffer "handle-sync" signal:
>
> application/x-rtp-sync, base-rtptime=(guint64)2490599386,
> base-time=(guint64)137714729, clock-rate=(uint)90000,
> sr-ext-rtptime=(guint64)2491725922,
> sr-buffer=(buffer)80c800069af6cadbd39457a5e959817b9484b862000003ed0010b1da81ca000c9af6cadb0116726f6f7440616f63632d617869732d646f6d656f6c640204726f6f7406094753747265616d6572000000;
>
> and at the same time from rtpsource "stats":
>
> application/x-rtp-source-stats, ssrc=(uint)2599865051,
> internal=(boolean)false, validated=(boolean)true,
> received-bye=(boolean)false, is-csrc=(boolean)false,
> is-sender=(boolean)true, seqnum-base=(int)-1, clock-rate=(int)90000,
> rtp-from=(string)192.168.3.27:50088,
> rtcp-from=(string)192.168.3.27:50089, octets-sent=(guint64)0,
> packets-sent=(guint64)0, octets-received=(guint64)1155650,
> packets-received=(guint64)1060, bitrate=(guint64)703428,
> packets-lost=(int)0, jitter=(uint)83, have-sr=(boolean)true,
> sr-ntptime=(guint64)15245907008652149115, sr-rtptime=(uint)2491725922,
> sr-octet-count=(uint)1094106, sr-packet-count=(uint)1005,
> sent-rb=(boolean)true, sent-rb-fractionlost=(uint)0,
> sent-rb-packetslost=(int)0, sent-rb-exthighestseq=(uint)18120,
> sent-rb-jitter=(uint)97, sent-rb-lsr=(uint)1470108312,
> sent-rb-dlsr=(uint)337017, have-rb=(boolean)false,
> rb-fractionlost=(uint)0, rb-packetslost=(int)0,
> rb-exthighestseq=(uint)0, rb-jitter=(uint)0, rb-lsr=(uint)0,
> rb-dlsr=(uint)0, rb-round-trip=(uint)0;
>
> Does anybody know how to obtain the damn time reference  from
> sr-rtptime/sr-ntptime to pipeline "absolute time" (aka the  one
> defined here http://cgit.freedesktop.org/gstreamer/gstreamer/tree/docs/design/part-synchronisation.txt)?
>
> TIA,
>
> pz
>
>
>
>
> 2012/6/26 Pazzo Da Legare <pazzodalegare at gmail.com>:
>> Dear Josh,
>>
>> Thank you very much for your links.
>>
>> I thought I couldn't find the right parameter to instruct rtspsrc to
>> propagate the time downstream (or better to say to use the rtsp source
>> time as clock reference) I was more than sure that it would have been
>> possible, but now you confirm that a "crazy" idea to manage sr-message
>> is the only (known) way to extract source reference: I'm trying to
>> follow exactly the same approach trying to extract absolute time from
>> rtspsrc and send a metadata event (GST_EVENT_TAG) through my pipeline.
>> The point is how to correlate internal absolute time (what you can get
>> with gst_clock_get_time()) and ntptime of RTCP protocol without
>> _error_ (i.e. taking into account source->rtspsrc transmission time)?
>>
>> I can intercept RtpSession information but I have no way to relate
>> (sr-ntptime, sr-rtptime) with the time (internal absolute time) of the
>> frame they are referring to. Any clue?
>>
>> BR,
>> pz
>>
>>
>>
>>
>> 2012/6/26 Josh Doe <josh at joshdoe.com>:
>>> On Tue, Jun 26, 2012 at 6:06 AM, Pazzo Da Legare
>>> <pazzodalegare at gmail.com> wrote:
>>>> Dear all,
>>>>
>>>> How can I convert gst_clock_get_time() value in an absolute time (with
>>>> year, month, day, ....). I'm playing with an rtsp camera, using
>>>> rtspsrc, and I would like to retrieve absolute time (ntp stream time)
>>>> across my pipeline. Is there an easy way to do that?
>>>>
>>>> from element's clock time now  (=Tue Jun 26 12:03:34 CEST 2012) I get
>>>> something like:
>>>>
>>>> 6112256969101111
>>>>
>>>> and it contains a bunch of thousands of seconds....
>>>>
>>>> I'm a little bit puzzled.
>>>
>>> gst_clock_get_time() will just give you a monotonically increasing
>>> integer. Subtracting the base time from that will give you the stream
>>> time:
>>> http://gstreamer.freedesktop.org/data/doc/gstreamer/head/manual/html/chapter-clocks.html
>>>
>>> If you're talking about the ISO 8601 timestamps that indicate the
>>> absolute UTC time, this doesn't appear to be implemented currently:
>>> http://cgit.freedesktop.org/gstreamer/gst-plugins-base/tree/gst-libs/gst/rtsp/gstrtsprange.c#n249
>>> http://tools.ietf.org/html/rfc2326#page-18
>>>
>>> A few issues. Not all servers support absolute time ranges. You can
>>> only get an absolute time if you requested the range in the same
>>> format, so rtspsrc would need to be given this information. Or you
>>> could extract a time range from SDP. Either way, you'd need a way to
>>> get the time to the application.
>>>
>>> This last part is what I'm interested. For now I'm sending a
>>> GST_TAG_DATE_TIME event to indicate the start time of the stream, so a
>>> buffer absolute time can be calculated from this absolute time and the
>>> stream time. If there's a better way (GstMeta?) then I'd like to hear
>>> it.
>>>
>>> -Josh
>>> _______________________________________________
>>> gstreamer-devel mailing list
>>> gstreamer-devel at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel