[MPlayer-users] Are mencoder lossless codecs really lossless?
jpboard2 at yahoo.com
Mon Jul 8 17:33:04 CEST 2013
My input file is an uncompressed raw YUV 4.2.2 format. I want to compress individual frames with a lossless codec. My mencoder implementation listed three such codecs it the man page:
* ljpeg: lossless jpeg
ffv1: FFmpeg's lossless video codec
* ffvhuff: nonstandard 20% smaller HuffYUV using VY12
I encoded my file using the following:
mencoder -ovc lavc -lavcopts ljpeg -oac copy -o out.avi in.avi
And then I converted it back to raw pixels with
mencoder -ovc raw -oac copy -o out2.avi out.avi
The above two steps should regenerate exactly the original file in.avi, right? I did this with the three lossless codecs I listed above. The problem is that my original input file in.avi is bigger than the final output file out2.avi: they should be exactly the same, right?
So, my question is this: are those codecs really lossless? Bit-exact lossless? Or are they merely pretty good?
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