[FFmpeg-devel] lavc/libvpxenc: Deprecate lossless option

Gyan ffmpeg at gyani.pro
Sun Feb 10 20:27:50 EET 2019

On 10-02-2019 05:36 PM, Kieran O Leary wrote:
> What ssim command did you use, and why use this over a hash muxer like
> framehash? I'm always on the lookout for losslessness verification methods.

The barebones command:

     ffmpeg -i main -i ref -lavfi ssim -f null -

framehash will be sensitive to data layout, so that comparing the same 
payload in planar vs packed format will yield different values. As the 
SSIM filter only works with planar formats, avfilter will take care of 
conversion, if needed, of both inputs.

Other than that, SSIM will present a rough measure of the shortfall if 
the transcode isn't lossless. A framehash is either a match or not.


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