[Elphel-support] Software flow for recording uncompressed/raw video

[Elphel Support]

Hello Shashank,

There is no "uncomressed" video in the camera, the video that is recorded is compressed. But with Elphel cameras it is possible to record video/images in such a way, that after processing (uncompressing) each pixel value differs from the 12-bit original sensor data by less than the sensor (unavoidable) noise for that pixel.

For high quality recording (design for post-processing) we use JP4 format
https://wiki.elphel.com/wiki/JP4
http://community.elphel.com/jp4
Each frame is recorded separately, making it ~2MB/frame when using 98% compression quality, 3-4MB for 100% (lossless)
Yes, it is possible to trigger camera, but as the recording time is measured in minutes, I would recommend to use software trigger (over the network) - latency is quite low and the less wires you use the better overall reliability of the system you get.
There are no other limits for the duration of recording but the SSD capacity. There are 2 ways to record - directly to the SSD partition (faster) or through the file system. When recording with the file system the data is recorded into the files of specified size (it is easier to manage reasonably sized ones), but when switching files there is no frame losses - 1st frame of the second file is the actual next captured frame after the last one in the first file.

Andrey


---- On Thu, 14 Sep 2017 02:28:20 -0700 Shashank Mutha<shashankmutha at gmail.com> wrote ---- 

Hello,    Please guide us on the software flow to record raw video. Also, what is the video quality and bit rate of the raw video and is it configurable. Further, is there an upper limit on the duration of recording (apart from the capacity of the SSD).
Can we also have a hardware trigger to start the recording (the stop time can be a few minutes from start).
Thank you for your time,
Regards,
Shashank

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