[x264-devel] About level_idc in sdp offer/answer

[Andrew Krupiczka]

Yes.

-  level_1_1 = 11, // 0x0B	typical for CIF at 7.5fps or even QCIF

-  level_3_1 = 31, // 0x1F 	typical for 720p at 30fps

In your case the level 0x0B is "lower/common/shared" supported by both clients.

Andrew

-----Original Message-----
From: Min Wang [mailto:ser.basis at gmail.com] 
Sent: Monday, July 16, 2012 10:06 AM
To: Mailing list for x264 developers
Cc: Andrew Krupiczka
Subject: Re: [x264-devel] About level_idc in sdp offer/answer

Hi Andrew

     thanks a lot.

profile-level-id=42E01f

     42 seems refer to profile_idc

    E0 seems refer to profile_iop
    1f seems to be the level_idc.


    Could you explain more on the what/which field is the lower/common/shared? Sorry for the dummy question.



kind regards.


min


On 07/16/2012 03:50 PM, Andrew Krupiczka wrote:
> Hi Min,
>
> In principle, the level_idc implies processing capability limits of your encoder/decoder.
> In the videoconferencing negotiation protocol situation normally you need to agree to tech. characteristics (incl. levels) which are supported by all involved devices - in your case it is a lower/common/shared level supported by both clients.
> Having said that, it is possible that a particular device could also support higher levels - I'd advise to look at device(s) spec. to see what max. level it is able to support.
> Best regards,
>
> Andrew
>
>
> -----Original Message-----
> From: x264-devel-bounces at videolan.org [mailto:x264-devel-bounces at videolan.org] On Behalf Of Min Wang
> Sent: Monday, July 16, 2012 9:30 AM
> To: x264-devel at videolan.org
> Subject: [x264-devel] About level_idc in sdp offer/answer
>
> Hi H264 Gurus:
>
>      I have a sip client sending video call with sdp:
>
>          Media Attribute (a): fmtp:97 profile-level-id=42E01f,
> packetization-mode=1
>
>     but replied by another client as
>
>        Media Attribute (a): fmtp:97 profile-level-id=42E00b
>
>
>        the difference seems to be:  level_idc.
>
>        Does the level_idc matter ?
>
>
>         Please see details at:
> http://java.net/nonav/projects/jitsi/lists/users/archive/2012-07/message/63
>
>
> kind regards.
>
>
>
> min
>
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