ONVIF Bridge/RTSP Server Reverse Playback and GoToTime Support

MIP
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1

Hi,

in ONVIF Bridge 2017 R2, it doesn’t appear that the reverse playback functions correctly.

In addition can you confirm that the Go To Time (6.9) command from the ONVIF spec referenced in the getting started guide also works?

2

Can you please provide working examples of how we can play in reverse, because following the info in the document does not work.

 But reverse playback does not work if Scale: -1.0 is set

  Rate-Control: yes 

 Scale: -1.0
3

Hi Josh,

I am unable to find any information about Go To Time command on the ONVIF spec, can you please provide a link to the documentation?

I will comeback you for reverse playback exmaple.

4

Hi Josh,

Here is a working exmaple:

Scale: -1.0

Range: npt=-\r\n

The end point of the range should be empty, so that it points to the begging of the playback footage.

If you want to control the speed, then set

Rate-Control: yes

then use the Scale header to set the speed value. Example

Scale: -1.5 for backwards

Scale: 1.5 for forwards.

Regards

5

Hi Josh,
When you start RTSP playback stream it is positioned at the beginning of the db (npt=0). If you start playing backwards from there, stream will just stop (and close). Therfore you should seek before that. Just have to add Range header in the play command. It could be either in relative time compared to db start (npt) or in absolute one - utc time (clock).
Tsvetomira alredy gave you an example about relative seek.
For the absolute it should look something like:
Range: clock=YYYYMMDDThhmmss.mmmZ-
Example:
Range: clock=20170807T142005.123Z-

6

Just to mention that npt is in seconds since db start.
There could be glitches if there are no continues recordings.

7

Hi,

can you provide an updated example of how to test/verify the reverse playback in vlc? The scale -1.0 is not working for us when testing with vlc, as per your quick start guide.

8

Hi Josh,

as per the Getting started guide, you can use the vlc command lines. Here is an example:

>vlc.exe --rate=-1.0 --start-time= “rtsp://:@/vod/”

I sniffed the communication between VLC and the Onvif Bridge. It seems that VLC is sending two consecutive PLAY commands without PAUSE command in between. One with Scale: -1.0 header and one with Range: npt=65000.000-\r\n. Preferably, you can send both headers in one PLAY command as well. Make sure that the start time you are pointing is the end of the recording you want to reverse play.