[Matroska-devel] [Cellar] Colour Format proposal

Steve Lhomme slhomme at matroska.org
Thu Jan 14 13:14:30 CET 2016


2016-01-14 13:11 GMT+01:00 Hendrik Leppkes <h.leppkes at gmail.com>:
> On Thu, Jan 14, 2016 at 1:04 PM, Steve Lhomme <slhomme at matroska.org> wrote:
>> 2016-01-06 23:30 GMT+01:00 Frank Galligan <frankgalligan at gmail.com>:
>>>
>>>
>>> On Tue, Jan 5, 2016 at 1:58 PM, Jerome Martinez <jerome at mediaarea.net>
>>> wrote:
>>>>
>>>> Thanks for your detailed proposal.
>>>> It is a lot of items, I am not expert in all domains but I have some
>>>> comments:
>>>
>>> Neither am I, but I figured we might as well start from a proposal and
>>> iterate from there.
>>>
>>>>
>>>> Name: MatrixCoefficients (or Matrix. You don't use "Colour" with
>>>> "Primaries" element, so I would not use it here too)
>>>
>>>  Sounds good to me.
>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Element Name: BitsPerChannel
>>>> Level:        5
>>>> ID:           [55][A2]
>>>> Mandatory:    ma
>>>> Multiple:     -
>>>> Default:      8
>>>> Type:         u
>>>> Description:  Number of bits per channel. This number may be less for
>>>> specific
>>>>               channels depending on the ColourFormat and
>>>> ChromaSubsampling.
>>>>
>>>>
>>>>
>>>> BitsPerChannel is misleading, used to be the technical count of bits.
>>>> I propose QuantizationBits or ValidBitsPerChannel
>>>> Not mandatory, not default (this value is often unknown)
>>>
>>> When authoring the video, I'm not sure why the software would not know the
>>> bits per channel. Can you describe a use case where the this is unknown?
>>
>> When remuxing an older file. Either from Matroska source or AVI or other.
>>
>> Now if elements are mandatory with a default value to "unknown" it's fine.
>>
>
> Whats the point of a mandatory element with an "unknown" default? Just
> make it optional then?

True.

> - Hendrik
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-- 
Steve Lhomme
Matroska association Chairman


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