[FFmpeg-user] Does converting to yuv444p by default make sense?
thljcl
jiachielee at live.com
Sun Jul 28 17:46:54 CEST 2013
When it comes to quality preservation, video editing, or lossless encoding;
yes, I would agree that “yuv444p” makes plenty of sense. “yuv444p” is a way
of re-encoding the entire 24-bit RGB information, which all color
information is preserved without any loss due to chroma subsampling. Lossy
encoding would cause the “generational loss” of quality. Chroma subsampling
or any other lossy encoding algorithms does not make sense for repeating
video editing process.
For video/film producers, it makes sense to keep the master copy of the
videos, for future editing or remastering process. That said, videos often
undergo lossy compression before commercial or non-commercial public
distribution. Lossy compression is done to achieve smaller file size, at the
expense of image quality. Lossy compression that is done over high-quality
source can preserve fairly reasonably high quality.
Ffmpeg is not the only tool I ever use. Most tools would have presets for
lossy compression, without giving us an option to choose our own settings.
Since most videos being distributed have undergone lossy compression of
certain levels, it makes sense for the many media players support those
popular formats.
If the sources have already underwent lossy compression, ffmpeg will choose
the “same color space” by default. For example, it would choose YUV420p by
default for JPEG image as sources. If the sources are PNG image, it would
choose YUV444p. Of course, the user can choose his own pixel format by
-pix_fmt.
There are free tools widely available to play H.264 encoded in YUV444p, such
as Media Player Classic Home Cinema included in K-Lite Codec Pack Mega.
Windows Media Player can play H.264 encoded in YUV444p with K-Lite Codec
Pack Mega. I’m not familiar with Mac OS X.
To me personally, I kind of like the way ffmpeg handle color space
conversion. Ffmpeg does have issues within its algorithm. YUV444p is not one
of them. My personal preference is that I would like to play highest-quality
video possible.
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