[FFmpeg-user] Obviating for webcam startup times for live webcam recording?
mathieu.bosi at gmail.com
Mon Feb 5 20:40:57 EET 2018
I am successfully recording videos from my webcam using ffmpeg under
windows with the
Direct Show source type with the following command line:
ffmpeg -f dshow -video_size 640x360 -rtbufsize 4MB -framerate 30
-pixel_format yuyv422 -i video="Logitech BRIO" out.mp4
All is working nicely, however I encountered the following problem:
since the ffmpeg command line is launched, the webcam takes some time
(around 2-3 seconds) to start streaming.
I know that this is a limitation that depends on the webcam way of
functioning / driver,
since this will happen with any other software accessing it (e.g. Skype).
The thing is that I would need video recording start to be as fast as
possible since the command line is started.
I was thinking that a possible solution would be to use a first instance of
ffmpeg to read the webcam,
keeping it running and continuously "streaming" it to a second ffmpeg
instance that could then
access the live stream of data only when needed.
I thought that in this way webcam video recording startup delay would be
eliminated or greatly reduced.
A note: I need to record more than one video, so I would let instance 1
always run, and only launch instance 2 when I want to record a new video.
So, my question are the following:
1. is such two "ffmpeg instances" configuration possible?
2. if so, what is the most efficient way to stream / pipe the video data
from instance 1 (hot webcam) to instance 2 (save to disk) with minimal
video quality loss?
Thanks for your help!
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