[libav-tools] libx264 option -x264-params

Torsten Römer torsten.roemer at luniks.net
Thu Aug 15 13:39:16 CEST 2013


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?

Torsten


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