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• ffmpeg proress 4444 produce low quality output

  3 mai 2017, par Panupat

  I have a bunch of HQ clips in Proress 4444 format with alpha I’m trying to scale down with ffmpeg. The output do produce the correct alpha, however the quality seems really bad. I’m curious if there’s something wrong with my command ?

  ffmpeg.exe -i in.mov -vf scale=iw/2:-2 -c:v prores_ks -profile:v 4444 -pix_fmt yuva444p10le -alpha_bits 16 out2.mov

  Above, output. Below, source.

  http://imgur.com/a/XYpWp

  I tried to add -colorspace bt709 -color_primaries bt709 -color_trc bt709 but seem to have no effect.

  the log is here - https://docs.google.com/document/d/19TdJwwDp0QD00f_7XB8sBAYMUWUrn2moRuCC6r6rI0k/edit?usp=sharing

  Any help appreciate, thanks !

• Anomalie #3177 (Nouveau) : padding auto n’existe pas

  4 mars 2014, par b b

  On a une règle qui tente de coller la valeur auto en tant que padding dans la dist :

  http://zone.spip.org/trac/spip-zone/browser/_core_/plugins/dist/css/layout.css#L73

  Pourtant cette valeur n’est pas reconnue et ne semble pas être "valide", cf :

  padding : [ | ] 1,4

  https://developer.mozilla.org/fr/docs/CSS/padding

  Si ce n’est pas voulu il serait bon supprimer ce padding : auto !important ;

• Emphasis level map with ffmpeg using NVENC

  2 novembre 2020, par ofer rubinstein

  I am trying to have different compression levels, to different regions in the video.
ffmpeg has something called "addroi", but it's just a recommendation and doesn't guarantee the absolute level of compression.
Nvidia NVENC has something called Emphasis Level Map, I am hoping this will be able to achieve an accurate level of compression per region.

  


  I am unable to find how to do this via ffmpeg executable, so I am starting to try to do this using the ffmpeg SDK.
Do you have any idea how to do this via the ffmpeg.exe, instead of using the SDK ?

  


  Here is what I am talking about in the NVIDIA documentation :

  


  https://docs.nvidia.com/video-technologies/video-codec-sdk/nvenc-video-encoder-api-prog-guide/index.html#emphasis-map