CODEWITHSUNDEEP
videoffmpegjpegrtspsnapshot
The Doctor
The Doctor

Reputation: 223

How to output a sequence of images in a loop with ffmpeg from rtsp stream

I am reading an RTSP stream from a surveillance camera and want to use ffmpeg to create a snapshot of the camera as jpeg. Principally it works to create a snapshot.jpg using the -update 1 option, but if it happens (what it does very often) that the client application reads the file while ffmpeg writes to it, the image is displayed only partially.

Hence I want to use ffmpeg to capture more than 1 images in a kind of ring buffer, so I can access the image captured just before the current one and have also the last n images as short history.

Though ffmpeg allows to create a series of jpgs, this seems infinite. Is it possible to tell ffmpeg to create images in a file pattern like this:

pic1.jpg, pic2.jpg, pic3.jpg, pic4.jpg, pic5.jpg and after pic5.jpg to start over again using pic1.jpg etc. This way it could consume a stream continuously without filling up my drive. Unfortunately something like -update 5 seems not to work (ffmpeg simply exits).

Principally I can also let it run infinitely and clean up all files older than n seconds, but that would introduce additional overhead and is IMHO not really clean programming compared to ffmpeg using this kind of ring buffer approach.

Any help would be appreciated.

Upvotes: 0

Views: 2899

Answers (1)

Gyan
Gyan

Reputation: 93068

You have to use the segment muxer.

ffmpeg -i input -f segment -segment_time 0.0001 -segment_format singlejpeg -segment_wrap 5 pic%d.jpg

Upvotes: 3

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