Collection of some interesting pre-calculations regarding resolutions, frame rates and speeds.
Lets see the options for resolution and frame rate of the GoPro Hero 3. Beware that the camera will be oriented vertical. Two things would be interesting to know.
- what would be the resolution and size of the result of an one-minute long clip after processing
- JPEG's can't have more than 65.536 pixels in any dimension - how long does the clip need to be to exceed this value.
Horizontal Resolution of 1 minute clip = Frame Rate * 60s JPEG Limit time = 65.536px / Frame Rate
of 1 minute clip
|WVGA||848 px||240 fps||14.400 x 848 ~ 12.2MP||4min 33s|
|720p||1280 px||120 fps||7.200 x 1.280 ~ 9.2MP||9min 6s|
|1080p||1920 px||60 fps||3.600 x 1.920 ~ 6.9MP||18min 12s|
|1440p||2560 px||48 fps||2.880 x 2.560 ~ 7.4MP||22min 45s|
|4K||3840 px||15 fps||900 x 3.840 ~ 3.5MP||1h 12min 49s|
|4K Cinema||4096 px||12 fps||720 x 4.096 ~ 2.9MP||1h 31min 1s|
Personally I believe that the best results would be achievable with 720p, 1080p or 1440p. The vertical resolution of WVGA is too small and might get pixelated. For 4K issues caused by the slow frame-rate might arise.
How does the speed of the GoPro Mount (e.g. car) affect the outside-world resolution?
v = 1 m/s
v = 5 m/s
v = 10 m/s
v = 30 m/s
v = 50 m/s
v = 220 m/s
|WVGA||848 px||240 fps||4 mm||21 mm||42 mm||0,13 m||0,21 m||0,92 m|
|720p||1280 px||120 fps||8 mm||42 mm||83 mm||0,25 m||0,42 m||1,8 m|
|1080p||1920 px||60 fps||17 mm||83 mm||0,17 m||0,50 m||0,83 m||3,7 m|
|1440p||2560 px||48 fps||21 mm||0,10 m||0,21 m||0,63 m||1,0 m||4,6 m|
|4K||3840 px||15 fps||67 mm||0,33 m||0,67 m||2,0 m||3,3 m||14,7 m|
|4K Cinema||4096 px||12 fps||83 mm||0,42 m||0,83 m||2,5 m||4,2 m||18,3 m|
What the heck are these numbers? Lets say I set the GoPro to mode 720p making 120 frames per second. It is mounted in a car which is driving with 10 m/s through the city. The table indicates an outside-world resolution of 83mm per pixel (frame). The camera moves 83mm between each two frames. To make more practical sense here: You are drving by a house with that setup. The house is e.g. 8,3 meters wide. With an outside-world resolution of 83mm the house would be 100 pixels wide in the final result. Which isn't actually very much.