Hello Laurie, On Sat, 8 Aug 2020 21:56:08 +0100 Laurence Tratt <lau...@tratt.net> wrote:
> On Sat, Aug 08, 2020 at 09:30:18PM +0200, Marcus Glocker wrote: > > Hello Marcus, > > >> I like your patch, which is better than my original! My only very > >> minor comment is whether we might want to document that it's safe > >> to put "0" in a "V4L2_CID_AUTO" settings, since the lowest value > >> one of those can be is 0x900 (judging by videoio.h)? At least, I > >> had to look to make sure it was safe :) > > Sorry, I lost you. Which control value exactly can be lowest > > 0x900? > > In this bit of your diff: > > #define CTRL_SHARPNESS 6 > - { "sharpness", 0, V4L2_CID_SHARPNESS, 0, 0, 0, 0, 0 }, > + { "sharpness", 0, V4L2_CID_SHARPNESS, 0, 0, 0, 0, 0, 0 }, > #define CTRL_WHITE_BALANCE_TEMPERATURE 7 > { "white_balance_temperature", > - 0, V4L2_CID_WHITE_BALANCE_TEMPERATURE, 0, 0, > 0, 0, 0 }, > + 0, V4L2_CID_WHITE_BALANCE_TEMPERATURE, > + V4L2_CID_AUTO_WHITE_BALANCE, 0, 0, 0, 0, 0 > }, > > it wasn't immediately obvious to me that the first "0" after > V4L2_CID_SHARPNESS wouldn't conflict with some other V4L2 setting. > But it turns out that all the V4L2_CID values are defined relative to > this: > > #define V4L2_CID_BASE (V4L2_CTRL_CLASS_USER > | 0x900) > > so "0" can't accidentally clash with anything. It's not a big deal :) Oh right, got it now :-) Yes, we should be safe by using '0' to indicate that a control has no auto control available without conflicting. > >> One other thing has occurred to me -- but can be done in a future > >> patch -- is that we probably want to be able to do: > >> > >> $ video white_balance_temperature=auto > > I was thinking about that as well but just not decided yet if we > > should introduce this or for now be compliant with the GUI where > > you would require to reset all settings to get back to auto. > > In a sense the command-line is already more expressive (you can, for > example, express arbitrary white balance temperatures when in the GUI > you have to use increments of 10), so I'm inclined to think that > allowing them to be more separate is no bad thing. Well yes, true. > [I personally think the GUI controls are very hard to use in > practise: they change so slowly that I find it almost impossible to > A/B anything. So I'm a bit biased against them!] I see your point. Lets add this to our backlog, as we say in Agile :-| > > Laurie > Marcus