[x264-devel] Re: Response from a vendor

[Måns Rullgård]

Peter Maersk-Moller <peter at maersk-moller.net> writes:

> Hi Loïc
>
> Thanks for your comments.
>
> Loïc Le Loarer wrote:
>> Can you show use the options you use to encode your stream and a small
>> video dump of the produced bitstream ?
>
> Config is as follows:
>
>    Geometry : 480x576
>    SAR : 5:8
>    Framerate : 25
>    I-Frames : 2 * Framerate
>    Bframes : 2
>    Bitrate : 1200
>    CBR : 1
>    Rate tol : 0.01
>    VBV : No
>    Cabac : 1
>    b_psnr : 0
>
> 60 secs. sample is available at http://www.optimalstream.net/tmp/sample.mp4
>
> Sample is produced with x264-snapshot-20060424-2245. A bit old, but
> it should do.

You should try with the latest version just to be sure.

>> One of the possible option which can be a problem is the use of High
>> Profile (8x8 transform or scaling matrix particulary).
>
> How do I see that ?
>
>> Please, everybody, don't be fooled by this kind of language, a decoder
>> must be compatible with the H.264 norm for given Profile/Level
>> combinaisons, being compatible with a given encoder is not an acceptable
>> answer, it is against interopability and have many bad results, a bit
>> like IE didn't support the whole HTML spec and added its own extension
>> creating "IE only" web sites.
>> Moreover, an encoder must also be compatible with H.264 norm and
>> produces bitstreams which are compliants with given Profiles and Levels.
>> If the Profiles and Levels of the encoder and the decoder matches, then
>> they can be used together.
>
> That's my line of thoughts. I'm trying to force the vendor to specify
> exactly what levels and profiles that they support, but unsurprisingly,
> some of them are vague on this.

As is usual in this business.

>> By the way, which STB vendor is it ?
>
> At this moment, I'm not at the liberty to tell excepts its Korean.

I could almost have guessed from the style of English they used.  

> I'm trying to find a vendor able and willing to deliver 1.000 H.264
> STBs for a large scale field test across a couple of countries in
> Scandinavia, but so far had little luck. Many vendors have plans,
> but can't deliver a single working sample, including Comtrend and
> Envivio which both have gone mysteriously silent on the topic.

Sounds all too familiar.  They all talk a great deal, but few will
actually deliver.  When you put some pressure on them, they start
ignoring you.

-- 
Måns Rullgård
mru at inprovide.com

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