7. 不同的源比SSIM,連參考意義都沒有。當然像這個例子要比的話也是有辦法的。像有些4:2:0/4:2:2/4:4:4對比中源有做up/down sampling、前期做up/down sampling和壓完了播放時再做甚至壓完了導入avs再做都是不同的,完全是四個始終沒法達到相同的變量在比較,那種測試再比SSIM什麼的就很搞笑了。這裡原始RGB片源作為a,壓制好的YUV作為b,將b轉成RGB,然後用Compare來比PSNR,例如
AviSource("RGB-Source.avi")
WhateverProcess()
拿這個東西去壓制,然後
a = AviSource("RGB-Source.avi")
b = xxxSource("YUV-Encoded.ext").Dither_Convert_YUV_TO_RGB()
Compare(a, b)
參數不加了,按情況自己調整。不過我記得目前缺少能直接吃入成10/16bit YUV4:4:4的源濾鏡,可能只能先把壓好的東西解碼成raw yuv,然後用rawsource之類的工具讀入,比較麻煩…這樣比較確實是同源的,如果不同方式處理之後壓出來的保證碼率相同的話是有比較價值的(或者做不到完全相同可以用bitrate-PSNR曲線)。另外注意比SSIM的話需要--tune ssim,比PSNR需要--tune psnr,否則psy-rd/trellis的算法本身對ssim/psnr影響都太大了…
つまんねー事聞くなよ!
I, personally, for me, believe (obviously sometimes) that my OS choice is right. That's me. I'm not telling you that you should believe it. Learn the facts, and the origins behind the facts, and make up your own damn mind. That's why you have one. (source)
I, personally, for me, believe (obviously sometimes) that my OS choice is right. That's me. I'm not telling you that you should believe it. Learn the facts, and the origins behind the facts, and make up your own damn mind. That's why you have one. (source)