[libav-tools] libx264 option -x264-params

Luca Barbato lu_zero at gentoo.org
Sun Aug 25 14:12:11 CEST 2013


On 15/08/13 13:39, Torsten Römer wrote:
> 
> Am 14.08.2013 17:20, schrieb Luca Barbato:
>> On 07/08/13 12:32, Torsten Römer wrote:
>>> Am 07.08.2013 09:59, schrieb Luca Barbato:
>>>> On 05/08/13 14:04, Torsten Römer wrote:
>>>>> Am 05.08.2013 13:21, schrieb Luca Barbato:
>>>>>> On 05/08/13 12:57, Luca Barbato wrote:
>>>>>>> On 29/07/13 20:47, Torsten Römer wrote:
>>>>>>>> I would like to use the libx264 option --blueray_compat, and since
>>>>>>>> it is
>>>>>>>> not available as private option in libav, I tried to use
>>>>>>>> -x264-params as
>>>>>>>> described in the documentation, but this option is unrecognized,
>>>>>>>> even in
>>>>>>>> the current 9.8 release that I just downloaded and built. What am I
>>>>>>>> missing?
>>>>>>> I'll add it, in the master branch you can use the x264-params to
>>>>>>> pass
>>>>>>> the x264 raw params (see documentation).
>>>>>> To make it clearer -x264-params "bluray_compat=1" works as
>>>>>> intended on
>>>>>> libav git.
>>>>>>
>>>>>> lu
>>>>> Nice, cheers!
>>>> Kieran pointed out bluray-compat=1 force-cfr=1 is the correct setting.
>>>>
>>>> I added a shortcut -bluray-compat" to also set the encoder as cfr so
>>>> you
>>>> can produce correct bluray bitstream with ease (assuming you are
>>>> feeding
>>>> the encoder correctly).
>>>>
>>>> lu
>>> Very nice the shortcut, it will be very useful also for applications
>>> like kdenlive (MLT?), where I think it may not be possible to pass raw
>>> parameters with the -x264-params parameter.
>>>
>>> It is just that libx264 now gives the following warning:
>>>
>>> [libx264 @ 0x331d8e0] NAL HRD parameters require VBV parameters
>>>
>>> I think two more libx264 parameters need to be set, --vbv-maxrate and
>>> --vbv-bufsize as suggested here:
>>> http://mewiki.project357.com/wiki/X264_Encoding_Suggestions#Blu-ray_Encoding
>>>
>>>
>> Good catch =) I'll add at least to the documentation the information.
>>
> If there are no shortcuts for vbv-maxrate and vbv-bufsize, it is
> necessary to use -x264-params to set them, where bluray-compat could
> also be specified, so isn't the shortcut -bluray-compat kind of
> redundant, if -x264-params has to be used anyway?

I guess the best would be adding a preset for it in the end, sounds good
to you?

lu





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