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REX MPC Tutorial
REX Lossless Tutorial

rev. 1.10

Recommended REX settings & latest encoder version


REX MPC Encoder version:
Mppenc.exe version 1.14
1.14 is latest so-called 'beta' version of mpc-encoder. This means, 1.14 is latest stable version.

Only if you follow the PiMP Standard for your backup in detail, you could use v 1.15r , which is an alpha version. 1.15r and 1.14 have been tested now for a long time. 1.14 is slightly better on some test-samples, 1.15r performs slightly better on some other test-samples. Because 1.15r is only an alpha version, it has a disadvantage: The songs are marked with an ugly tag: 'unstable/experimental profile, encoder version'.

Recommended REX Flac encoder version: flac.exe 1.1.0

Recommended REX WavePack version: Wavepack 3.97 --> 4.0
Please wait before using it, until 4.0 stable is released.

Some possible REX MPC settings:

REX Quality levels

Estimated averaged bitrate

Minimum :

--quality 7 --xlevel

            ca.   220 kbit/s

 

ß

increasing quality & filesizes

--quality 7    --ms 15 --xlevel

            ca.   223 kbit/s

--quality 7.5 --ms 15 --xlevel

            ca.   245 kbit/s

--quality 8 --xlevel

            ca.   265 kbit/s

--quality 8    --ms 15 --xlevel

            ca.   266 kbit/s


What's the matter with --ms 15 switch ?

Answer: --ms 15 is the most advanced joint stereo/stereo mode in MPC. Quality (q) 5 uses ms11; q6 uses ms12; q7, q8, q9 use ms13 , q10 uses ms15 by default.
So, if you want to benefit from the addional safety offered by ms15, you need to add this switch.
Is there any possibility, that ms15 would reduce the quality of sound ?
No. The developer of MPC, Mr. F. Klemm, has confirmed, that adding ms15 can only improve the quality.
Are filesizes increasing by ms15 switch ?
For common music you will see nearly none increase of filesize. The bitrates will increase about 1-3 kbit/s at a level of q7-q8, so the bitrate increase is neglectable.
(Only certain (not all !) mono-music will have a remarkable bitrate increase, if you compare the encoding at e.g. q7 with q7 ms15.)
If you add ms15 to a lower quality level like q5, you will see a higher bitrate increase, but at this q-level the functionality, advantage of adding ms15 has been proven clearly.
What is the advantage of adding --ms 15 ?
If you listen to your stereo music via 4-6 speakers by applying Logic7/DPL2, you could suffer from artefacts, especially at lower q-levels like q5, q6. Adding --ms 15 even to q5, solves the problem. And the bitrate of q5 ms15 is clearly less than pure q6 !
So, adding ms15 to q-levels below q10, helps in every case to avoid artefacts, which might result by stereo/multichannel processing, separation.

Does it make sense, to use higher MPC q-levels than q 8, like q9 or q10 ?

It does not make much sense. Look at the listening abilities of the whole population, which is more or less distributed like a Gaussian bell curve. A few people are unfortunately more or less 'deaf'. To this category could be counted people, who cannot differentiate between original wave sample and the according 64 or even 128 kbit/s MP3/MP3pro/WMA/Ogg compression, by ABX blind tests. Then there is a big number of people, who have the abilities to recognize 128 kbit/s in e.g. mp3 or even mpc from the original, but who cannot between mpc @ q5 or q6. Another group of people is able to recognize mpc @ q6, q7, still, but cannot @ q7 or q8 anymore. Only a small minority of people is able to recognize mpc @ q7 or q8.
So, if you have proven only yourself ! by ABX blind testing, that the usage of mpc @ levels higher than q8 (i.e. q9, q10) has helped to let vanish those artefacts, you were able to listen at lower q-levels, in this case, it would be justified to use q9 or q10.
For scientific, developing interests, it would be very helpful, if you write about these experiences e.g. at http://www.hydrogenaudio.org.
Another reason, why q9, q10 does not make much sense:
The bitrate of q9, q10 is already so high, that going Lossless is an option. Lossless compression can achieve bitrates around 400 kbit/s for some classic albums e.g., for other music higher bitrates. If you go lossless instead of mpc, then you don't need to bother of casual artefacts. Lossless is the original, no discussion/ABX blind testing necessary.