[x264-devel] Lossless H.264 encoding (8 bit grayscale video)

[Jason Garrett-Glaser]

2008/12/29 Ram prasad <ramprasad85 at gmail.com>:
> Thank you for the response.
> As i had mentioned I am try to compress RGB 24 bit VGA video.
> My input has mainly grayscale data and very little color information.
> I have succeeded in separating the two. now i have an 8 bit grayscale video
> (and *r*e*s*i*d*u*e*).
> The previous reply had the steps to make x264 work with yuv 420. Thank you
> very much for that.
> Before i start with that i feel if x264 works with YUV 4:0:0, it can be used
> to compress 8-bit video.
> I also think if this feature is 'added' to x264, it will be become possible
> to use it in many other useful ways easily.
> Can you kindly tell me the steps to make x264 accept YUV 4:0:0.
> Thank you

It costs almost no bits to encode a chroma difference of zero--all you
have to do is convert the video to YV12 by adding null chroma channels
(memsetted to 128).  I tried adding 4:0:0 support a while back, but it
turned out to be pretty pointless as it saved about 0.01% bitrate.

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