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Paul Libbrecht | 26 May 2012 10:27
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Video media-types insufficient?


hello dear Media-types' expert,

the other day, I played with the nifty new video element of HTML5 which seems to be fairly well implemented.
This element allows a list of sources together with their media-type so that the browser can find the
"video format" that it can play.
This element is perfectly following the idea of a media-type's characterization of an exploitable format.

However, this characterization is insufficient: the same media-type for videos can be encode data in
multiple codecs and these are not encoded in media-types:

I met this while using the video/mp4 media-type and realized that our default encoding, the mpeg4 codec,
did not play in iPad.
So I used the same video element, with a src of media-type pointing to an mp4 file that uses the h264 codec.
This one plays on iPad.

To me, this is a clear failure of the media-type video/mp4: it does not express sufficiently the
playability on a device.

Is this something well known?
Are there maybe media-type parameters that could help?
Are newer video media-types better on this respect?

thanks in advance

Paul
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Roni Even | 26 May 2012 11:53
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Re: Video media-types insufficient?

Hi,
I think this should be discussed in payload WG
Roni Even

> -----Original Message-----
> From: ietf-types-bounces <at> ietf.org [mailto:ietf-types-bounces <at> ietf.org]
> On Behalf Of Paul Libbrecht
> Sent: Saturday, May 26, 2012 11:28 AM
> To: IANA Media types
> Subject: [ietf-types] Video media-types insufficient?
> 
> 
> hello dear Media-types' expert,
> 
> the other day, I played with the nifty new video element of HTML5 which
> seems to be fairly well implemented. This element allows a list of
> sources together with their media-type so that the browser can find the
> "video format" that it can play.
> This element is perfectly following the idea of a media-type's
> characterization of an exploitable format.
> 
> However, this characterization is insufficient: the same media-type for
> videos can be encode data in multiple codecs and these are not encoded
> in media-types:
> 
> I met this while using the video/mp4 media-type and realized that our
> default encoding, the mpeg4 codec, did not play in iPad.
> So I used the same video element, with a src of media-type pointing to
> an mp4 file that uses the h264 codec. This one plays on iPad.
>
(Continue reading)

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Magnus Westerlund | 28 May 2012 08:43
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Re: [payload] Video media-types insufficient?

Hi,

Roni, if I understand correctly this is about the ISO based mp4 file
format and not the RTP payload format. Thus not really a question for
the Payload WG.

My question to Paul, does you and the browser use the codecs and
profiles parameter that are defined for this type. Please see
http://www.rfc-editor.org/rfc/rfc6381.txt

That is intended to more detailed express which profiles and codecs that
are included in the media type.

Cheers

Magnus

On 2012-05-26 11:53, Roni Even wrote:
> Hi,
> I think this should be discussed in payload WG
> Roni Even
> 
>> -----Original Message-----
>> From: ietf-types-bounces <at> ietf.org [mailto:ietf-types-bounces <at> ietf.org]
>> On Behalf Of Paul Libbrecht
>> Sent: Saturday, May 26, 2012 11:28 AM
>> To: IANA Media types
>> Subject: [ietf-types] Video media-types insufficient?
>>
>>
(Continue reading)

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Gmane