Re: [RFC] DV timings spec fixes at V4L2 API - was: [PATCH 1/8] v4l: add macro for 1080p59_54 preset

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em 04-07-2011 19:47, Laurent Pinchart escreveu:
> Hi Mauro,
> 
> On Monday 04 July 2011 18:09:18 Mauro Carvalho Chehab wrote:
> 
> [snip]
> 
>> 1) PRESET STANDARDS
>>    ====== =========
>>
>> There are 3 specs involved with DV presets: ITU-R BT 709 and BT 1120 and
>> CEA 861.
>>
>> At ITU-R BT.709, both 60Hz and 60/1.001 Hz are equally called as "60 Hz".
>> BT.1120 follows the same logic, as it uses BT.709 as a reference for video
>> timings.
>>
>> The CEA-861-E spec says at item 4, that:
> 
> [snip]
> 
>> At the same item, the table 2 describes several video parameters for each
>> preset, associating the Video Identification Codes (VIC) for each preset.
> 
> This might be a bit out of scope, but why aren't we using the VICs as DV 
> presets ?

I had the same question after analyzing the specs ;)

That's said, abstracting from the spec could be a good idea if we have newer
versions of the spec re-defining the VICs.

Maybe the right thing to do would be to rename the presets as:

V4L2_DV_CEA861_VIC_16
V4L2_DV_CEA861_VIC_35_36
...

(or course, preserving the old names with compatibility macros)

Cheers,
Mauro