[libav-tools] libx264 option -x264-params

Torsten Römer dode at luniks.net
Sun Aug 25 17:10:20 CEST 2013


/Am 25.08.2013///14:12/, schrieb Luca Barbato:/

> 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?
Sounds like a very good idea to me!

Cheers,
Torsten


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