New Custom Quantization Matrices - EQM AVC Series. Last update: EQM AVC-HR 2005-08-01

[henryho_hk]

Do we have a "compressibility test" for MPEG4-AVC?

[Selur]

would it make sense?

[henryho_hk]

Somehow, unless we have some general rules describing terms like "high bitrate", "difficult materials", etc. for MPEG4-AVC (say, with respect to x.264). I am asking myself questions like "how would this movie look like if I encode it into xxxMB using x.264?" I think something like a compressibility test would help.

[Sharktooth]

compressibility test is like for xvid. except you have to use CRF 18 istead of CQ2.
also the avc matrices are really becoming obsolete and useless (at least for x264) since VAQ and Psy-RDO,

[henryho_hk]

If we are doing a sampled compressibility test, do we need to discard the frames of "artificial" scene changes?

[Sharktooth]

as a rule of thumb it would be better to discard them but the theoretical right way is just rising the patial comp.test compression value/percent by e few points to compensate the difference of partial encode scenechanges number vs the final encode scenechanges effective or approximated number.

[xxthink]

Would you like to give some idear or papers about how to train a custom quantization matrix?

[Sharktooth]

http://en.wikipedia.org/wiki/Quantization_(image_processing)#Frequency_quantization_for_image_compression
how to "train" depends on what you want to obtain once you got "how" quantization matrices work.