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Re: [MSE] F2F discussion items

From: Pierre-Anthony Lemieux <pal@sandflow.com>
Date: Tue, 29 Apr 2014 15:46:20 -0700
Message-ID: <CAF_7JxBSW8u-4iEeEec7eV4a4qqi+gR62H-RcrVthMdKdA-4LQ@mail.gmail.com>
To: David Singer <singer@apple.com>
Cc: Paul Cotton <Paul.Cotton@microsoft.com>, "public-html-media@w3.org" <public-html-media@w3.org>
Hi David,

> The MP4 file format discussion list.

Do you mean mp4-sys, or something else? Just trying to the reference
right so that I can understand the context of and provide input on
"but on the mpeg list there was exactly the opposite suggestion, that
there be only one box."

> Something for ‘debugging and inspection’ is quite unsuitable for being both
> syntax-constrained and constrained to a fixed vocabulary.

Ok. Well, I am sure a 'kind' box would have been used if one had
existed back then. I am merely pointing out that there will be ISO
BMFF files out there with 'kind' encoded elsewhere.

Thanks,

-- Pierre

On Tue, Apr 29, 2014 at 9:57 AM, David Singer <singer@apple.com> wrote:
>
> On Apr 29, 2014, at 9:48 , Pierre-Anthony Lemieux <pal@sandflow.com> wrote:
>
>> Hi David,
>>
>>> But on the mpeg list there was exactly the opposite suggestion,
>>> that there be only one box.
>>
>> Which MPEG list?
>
> The MP4 file format discussion list.
>
>>
>>> That’s inappropriate, I think.  And strange.
>>
>> Uh. Ok. Why?
>
> "name is a null-terminated string in UTF-8 characters which gives a human-readable name for the track type (for debugging and inspection purposes). “
>
> It explains the type of track.  Typical common practice is to put in a string from the spec.:
>
> ‘vide’   Video track
> ‘soun’   Audio track
> ‘hint’      Hint track
> ‘meta’      Timed Metadata track
> ‘auxv’      Auxiliary Video track
> ‘text’      Timed text track
> ‘subt’      Subtitle track
>
> Something for ‘debugging and inspection’ is quite unsuitable for being both syntax-constrained and constrained to a fixed vocabulary.
>
>>
>> Best,
>>
>> -- Pierre
>>
>> On Tue, Apr 29, 2014 at 9:42 AM, David Singer <singer@apple.com> wrote:
>>>
>>> On Apr 28, 2014, at 20:27 , Pierre-Anthony Lemieux <pal@sandflow.com> wrote:
>>>
>>>> Hi David,
>>>>
>>>> Some data points/questions below.
>>>>
>>>>> Quantity:          Zero or more
>>>>
>>>> Does this mean that more than one "kind" box can be associated with a
>>>> single track? A given timed text track can serve multiple purposes,
>>>> e.g. both SDH and subtitle, and hence be associated with multiple
>>>> kinds.
>>>
>>> OK.  But on the mpeg list there was exactly the opposite suggestion, that there be only one box.
>>>
>>>>
>>>>> contains the track ‘kind’ as defined <<by the W3C spec //
>>>>> section X of this spec. // whatever .>>.
>>>>
>>>> Also, the 'kind' defined in HTML might not be sufficient alone to
>>>> cover common kinds of timed text out there, e.g. 'commentary',
>>>> 'large'/'Text for the Visually Impaired', 'easyreader', 'karaoke',
>>>> etc…
>>>
>>> There has to be some agreement what the kinds mean;  we can’t have random communities inventing kinds and then finding they use the same word with different meanings.  I think that the w3c needs to document them, and if you are not in the w3c’s spec/radar, you are on your own.
>>>
>>>>
>>>>> Container:        User data box (‘udta’)
>>>>
>>>> At least one specification (Ultraviolet) use the 'name' field of the
>>>> 'hdlr' box to carry a comma-separated list of kinds for the timed text
>>>> track.
>>>
>>> That’s inappropriate, I think.  And strange.
>>>
>>>>
>>>> Thanks,
>>>>
>>>> -- Pierre
>>>>
>>>> On Wed, Apr 9, 2014 at 7:15 AM, David Singer <singer@apple.com> wrote:
>>>>>
>>>>> On Apr 9, 2014, at 15:25 , Paul Cotton <Paul.Cotton@microsoft.com> wrote:
>>>>>
>>>>>> [MSE] Summary of "Resolving Bug 24370" thread and proposed next steps, Aaron
>>>>>> http://lists.w3.org/Archives/Public/public-html-media/2014Apr/0043.html
>>>>>>
>>>>>
>>>>>
>>>>> I am checking with the MP4 experts at MPEG, but my inclination is that the box definition belongs in the W3C spec. anyway and would be registered at the MP4RA.  Something like
>>>>>
>>>>> 1.1.1.1       Definition
>>>>>
>>>>> Box Type:        ‘kind’
>>>>> Container:        User data box (‘udta’)
>>>>> Mandatory:      No
>>>>> Quantity:          Zero or more
>>>>>
>>>>> The kind box contains the track ‘kind’ as defined <<by the W3C spec // section X of this spec. // whatever .>>.
>>>>>
>>>>> 1.1.1.2       Syntax
>>>>>
>>>>> aligned(8) class TrackKindBox
>>>>>  extends FullBox(‘kind’, version = 0, 0) {
>>>>>  string   thekind;
>>>>> }
>>>>>
>>>>> 1.1.1.3       Semantics
>>>>>
>>>>> thekind is a null-terminated string in UTF-8 characters, giving a track kind as defined by <<section X of Y>>.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> David Singer
>>>>> Manager, Software Standards, Apple Inc.
>>>>>
>>>>>
>>>>
>>>
>>> David Singer
>>> Manager, Software Standards, Apple Inc.
>>>
>
> David Singer
> Manager, Software Standards, Apple Inc.
>
Received on Tuesday, 29 April 2014 22:47:08 UTC

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