[x264-devel] How to set level programmatically

[BugMaster]

On Fri, 24 May 2013 12:38:51 +0200, Sergio Garcia Murillo wrote:
> El 24/05/2013 12:32, Jason Garrett-Glaser escribió:
>> On Fri, May 24, 2013 at 1:47 AM, Sergio Garcia Murillo
>> <sergio.garcia.murillo at gmail.com> wrote:
>>> +1
>>>
>>> Some conferencing equipment matches the level in the SPS with the
>>> profile-level-id negotiated via SDP and reject it if they don't match (even
>>> if the h264 stream comply with the level constrains). So currently I have to
>>> check all output nals for SPS ones and rewrite the value.
>> Wouldn't it be vastly easier to just set i_level_idc? This seems like
>> orders of magnitude more effort than is necessary...
>>
> Would love it, but in my tests, the i_level_idc is only used to apply 
> the constrains to the encoding, but the profile-level-id set in the SPS
> is calculated internally and may not match the i_level_idc.

> Best regards
> Sergio
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What? In libx264 i_level_idc doesn't apply any constrains to the
encoding. It is used only as tag and written directly to level_idc
field in SPS. The only exception is special value 9 for baseline/main
where it used to signal 1b level which changed internally to
level_idc=11 and constraint_set3_flag=1.