无损RGB24到YUV444转换 [英] Lossless RGB24 to YUV444 transformation

问题描述

我目前正在尝试使用FFMPEG上的H264对RGB24文件进行无损压缩.但是，事实证明，在H264压缩(RGB24-> YUV444)中使用的色彩空间转换是有损的(我猜测是由于量化误差).在用无损H264压缩RGB24文件之前，还有其他方法可以使用(例如程序)将RGB24文件无损转换为YUV吗?

I am currently attempting to undergo lossless compression of RGB24 files using H264 on FFMPEG. However, the color space transformation used in the H264 compression (RGB24 -> YUV444) has proven to be lossy (I'm guessing due to quantisation error). Is there anything else I can use (eg a program) to transform my RGB24 files to YUV losslessly, before compressing them with lossless H264?

最终目标是压缩RGB24文件，然后对其进行解压缩，使解压缩后的文件与原始文件完全匹配.例如RGB24-> YUV444->压缩YUV44->解压缩的YUV444-> RGB24.

The ultimate goal is to compress an RGB24 file then decompress it, with the decompressed file exactly matching the original file. eg RGB24 -> YUV444 -> compressed YUV44 -> decompressed YUV444 -> RGB24.

这有可能吗?

推荐答案

这是我在此处给出的答案的副本/粘贴内容: RGB帧编码-FFmpeg/libav

This is a copy/paste from my answer here: RGB-frame encoding - FFmpeg/libav

让我们看看色彩空间的转换.

lets look at the colorspace conversion.

void YUVfromRGB(double& Y, double& U, double& V, const double R, const double G, const double B)
{
    Y =  0.257 * R + 0.504 * G + 0.098 * B +  16;
    U = -0.148 * R - 0.291 * G + 0.439 * B + 128;
    V =  0.439 * R - 0.368 * G - 0.071 * B + 128;
}

并插入一些虚拟值:

R = 255, G = 255, B = 255
Y = 235

R = 0, G = 0, B = 0
Y = 16

如您所见，范围0-> 255被压缩为16->235.因此，我们显示了RGB颜色空间中的某些颜色在(数字)YUV颜色空间中不存在.因此，根据定义，转换是有损耗的.

As you can see, the range 0 -> 255 is squished to 16 -> 235. Thus we have shown that there are some colors in the RGB colorspace that do not exist in the (digital) YUV color space. Hence the conversion is lossy by definition.

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