Possiamo rifarci ai suggerimenti sul manuale della vecchia DCS-5300G A1 802.11g risalente al 2004. All'epoca con lo standard WiFi G a 54Mbps & con le velocità ADSL il produttore si spendeva a scrivere dei dettagli in più per l'utente riguradanti queste impostazioni.
Recommendations for setting video for the best performance:
"Best performance" means the image refresh rate should be the fastest possible and the video quality should be the best possible at the lowest network bandwidth possible. Three factors, Maximum frame rate, Fix bit rate, and Fix quality in the Video Configuration page, are related to performance.
Recording settings for real-time motion images
To achieve a real-time visual effect, the network bandwidth should be large enough to transmit 20 image frames per second (fps) or more. If you are on a broadband network over 1Mbps, you can set Fix bit Rate to 1000Kbps or 1200Kbps, or set Fix quality to achieve the maximum frames. The maximum frame rate is 25 in 50Hz system and 30 in 60Hz system. If your network bandwidth is more than 384Kbps, you can adjust Fix bit rate according to your bandwidth and set the maximum frame rate of 25 to 30. If the images vary dramatically in your environment, you may slow down the maximum frame rate to 20 to decrease the transmitted data for better video quality. Since the human eye could not easily differentiate between 20 and 25 or 30 frames per second, the slower frame rate will not be noticed. If your network bandwidth is below 384 Kbps, you should adjust the bit rate according to your bandwidth and experiment to allow for the best frame rate that can be achieved. The faster frame rate in a slow network will blur the images. You may also try to choose 352x240 in size option for better images or 704x480 for
larger image size. Because the network has burst constraints and everyone's environment is not the same, any poor connection will impair normal performance.
Fonte: D-link DCS-5300G Manual pag. 49
La soglia indicata coincide con le misurazioni di questo caso. Purtroppo il traffico dati deve viaggiare oltre i confini nazionali accumulando ritardi e degradazioni. Di sicuro intorno a quella soglia non è possibile usare né la massima risoluzione né tantomeno la massima frequenza di fotogrammi al secondo; anzi, come consigliato, occorre vagliare con delle prove sul campo la migliore combinazione di questi due fattori in funzione della velocità risultante.
