[FFmpeg-trac] #2343(avformat:new): Stream is blocked by 20 seconds or more when reading an mjpeg stream at low resolutions
FFmpeg
trac at avcodec.org
Sun Mar 10 23:11:07 CET 2013
#2343: Stream is blocked by 20 seconds or more when reading an mjpeg stream at low
resolutions
-------------------------------------+------------------------------------
Reporter: virtuald | Owner:
Type: enhancement | Status: new
Priority: wish | Component: avformat
Version: git-master | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+------------------------------------
Comment (by DonMoir):
I found with IP cameras, there can be a long delay on open. Generally
speaking, each IP camera has it's own best way of opening and sometimes
multiple ways of opening for same camera. There are some generic types
like: rtsp:// http:// These URL's are good enough for basic playback but
allow no additional control like pan,tilt,zoom (PTZ) and can introduce an
unwanted delay. I am finding it necessary to provide a special open call
for IP cameras. For testing I am setting max_analyze_duration to 0. In the
case of the camera I am testing with, I know it's mjpeg, how to control
PTZ, etc. So it boils down to 'knowing' the camera. There have been some
attempts to formalize but its not complete. The IP camera interfaces are
all over the place.
I have a long way to go on the above, but one thing for sure is I don't
want delayed video for a real time LAN based camera. For testing, I ignore
all timing and display the frames as fast as they arrive. The timing
itself is not to much of an issue, but the initial delay can throw things
way off in terms of seeing real time video. Like if I wave my hand in
front of the camera I want to see it as soon as possible and not 5 to 10
seconds later.
A generic open in this case is just not going to work well.
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2343#comment:2>
FFmpeg <http://ffmpeg.org>
FFmpeg issue tracker
More information about the FFmpeg-trac
mailing list