[FFmpeg-trac] #1753(undetermined:new): Delay output for X seconds

FFmpeg trac at avcodec.org
Wed Sep 19 17:43:36 CEST 2012

#1753: Delay output for X seconds
             Reporter:  burek        |                     Type:
               Status:  new          |  enhancement
            Component:               |                 Priority:  wish
  undetermined                       |                  Version:
             Keywords:               |  unspecified
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
 It would be nice to add a feature where the output could be delayed for
 certain amount of time (specified in seconds or hh:mm:ss.mmm). One use
 case for this might be the case where we want to capture the video, only
 when a certain event occurs (like lightning bolt, robbery or trespassing
 for example). If we start capturing the output at that exact moment, we
 might loose some valuable time, but if the output was buffered, then
 capturing would start in the past, enabling people to record an important

 How to make use of the feature?

 Start one ffmpeg to capture and buffer the webcam input (the output will
 start after 10 seconds and will continue real-time, always being late for
 10 seconds, comparing to the current time):
 ffmpeg -f v4l2 -i /dev/video0 -vf delay 10 -af delay 10 -f mpegts

 Start another ffmpeg only when some important event occurs (triggered by
 the sensor or something similar):
 ffmpeg -f mpegts -i udp://localhost:1234 -map 0 -c copy capture.avi

 Obviously capture.avi will start recording from the past, considering the
 current time the event was triggered, which will allow the beginning of
 the event to get recorded as well.

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1753>
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