btw with mine when the CBR is set after reset the bit rate does not increase to the value set. First you must set to VBR and then back to CBR.
To set to VBR change the BitRateControlSelect=1 to BitRateControlSelect=0
eg
VBR Set
curl -s --user 'adminass' '192.161.10.241/form/ExtVideoparaCfg?ie6need=on&Payload=0&resolution=37&framerate=25&IPRate=50&BitRateControlSelect=0&quality=4&BitRate=6048000&_=1703415212493'
then CBR Set to get correct bitrate.
curl -s --user 'adminass' '192.161.10.241/form/ExtVideoparaCfg?ie6need=on&Payload=0&resolution=37&framerate=25&IPRate=50&BitRateControlSelect=1&quality=4&BitRate=6048000&_=1703415212493'