Save record files by start time and end time from hikvision nvr.
# workspace
mkdir -p /home/nvr/lib
cd /home/nvr
# download sdk
wget http://download.hikvision.com/UploadFile/SDK/CH-HCNetSDKV6.0.2.2_build20181213_Linux64.zip
unzip CH-HCNetSDKV6.0.2.2_build20181213_Linux64.zip
#copy the so lib we need
cp CH-HCNetSDKV6.0.2.2_build20181213_Linux64/lib/lib* lib/
cp -r CH-HCNetSDKV6.0.2.2_build20181213_Linux64/lib/HCNetSDKCom/ lib/
# modify lb_library_path
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/nvr/lib:/home/nvr/lib/HCNetSDKCom
source ~/.bashrc
# compile
g++ -o yohonvr yohonvr.cpp -lhcnetsdk -lHCCore -lhpr -lHCCoreDevCfg -L ./lib -L ./lib/HCNetSDKCom# example: ./yohonvr 127.0.0.1 admin 123456 33 1553045839 1553045939 /tmp/save.mp4
./yohonvr [IP] [PORT] [USER] [PASSWORD] [CHANNELNO.] [START_TIMESTAMP] [END_TIMESTAMP] [SAVE_PATH]Please notice that hikvision IPCamera's start channal number is 33.
# using ffmpeg to encode as mp4.
# see as: https://trac.ffmpeg.org/wiki/Encode/H.264
# remove the audio by [-an]
# crf: The range of the CRF scale is 0–51, where 0 is lossless, 23 is the default, and 51 is worst quality possible. A lower value generally leads to higher quality, and a subjectively sane range is 17–28. Consider 17 or 18 to be visually lossless or nearly so; it should look the same or nearly the same as the input but it isn't technically lossless.
# A preset is a collection of options that will provide a certain encoding speed to compression ratio. A slower preset will provide better compression (compression is quality per filesize).
# example:
ffmpeg -i test.mp4 -preset fast -crf 19 -an -codec:v libx264 -maxrate 4M -bufsize 8M encoded_test.mp4
author: andybrier@qq.com