Tested on Dahua cams only, doesn't work on HiWatch DS-N241W
Extracting absolute timestamp of each frame for RTSP stream(H.264)
Compiled FFMpeg and sources, since timestamp extraction requires internal <libavformat/rtsp.h>
header file.
export ff_src=$HOME/ffmpeg_sources
export ff_bld=$HOME/ffmpeg_build
PKG_CONFIG_PATH="$ff_bld" ./configure --prefix="$ff_bld" --pkg-config-flags="--static" --extra-cflags="-I$ff_bld/include" --extra-ldflags="-L$ff_bld/lib" --bindir="$ff_bin" --enable-gpl --enable-nonfree
PKG_CONFIG_PATH="ff_bld/lib/pkgconfig/" gcc -I$ff_src/ main.c -o main.out `pkg-config --cflags --libs libavformat libswscale` -lvdpau -lX11 -lva-x11 -lva-drm