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

[Min Wang]

HI Andrew

      Oh. cool. Thanks a lot!




min

On 07/16/2012 04:26 PM, Andrew Krupiczka wrote:
> 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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>>      
>