WWDC17で新しく発表された画像フォーマットHEIFを使ってみた - Qiitahttp://qiita.com/tamanyan/items/cac337e8d08fb7eb2c2d …
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Replying to @nico_lab
これでもできる ffmpeg -i input -vcodec libx265 hoge.265 MP4Box -add-image hoge.265:primary -ab heic -new image.heic https://gpac.wp.imt.fr/2017/06/09/gpac-support-for-heif/ …
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Replying to @nico_lab
oh, found you here :) seems no library can do tiles split like iOS 11 do. I dont know if that affects compression rate or not, but parallelism is good.
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Replying to @fcicq
crf 使えば圧縮率変えられる ffmpeg -i {source} -vcodec -pix_fmt yuv420p -codec:v libx265 -crf 15 -preset placebo -x265-params info=0 -f hevc temp.hvc MP4Box -add-image temp.hvc -ab heic -new output.heichttps://qiita.com/yohhoy/items/fac992c335fa4fbbbbea …
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Replying to @nico_lab
Not this one. look at this log, a 4032x3024 photo is actually 48 tiles of 512x512 + 320x240 thumbnails.https://gist.github.com/rcombs/fa1c860615fa9ee6620ef70f98c95084 …
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Replying to @fcicq
tile 圧縮って vpx みたいだ https://en.wikipedia.org/wiki/VP9#Technology …
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Replying to @nico_lab
hmm? no? tile is like this http://omoidebako.jp/blog/wp-content/uploads/2017/09/heif_image1-930x472.png … from http://omoidebako.jp/blog/ios11-heif/ …
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single image vs tiled heif ~= baseline jpeg vs progressive jpeg. but there are more differences. tiled image can be en/decoded in parallel, and unused parts can be ignored on decoding if out of the view.
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