more on mp3 #1566

Job	Run time
macos-latest: clang++ Release Threads	33m 50s
macos-latest: clang++ Release OneTBB	2m 11s
macos-latest: clang++ Release PaRSEC	4m 36s
ubuntu-20.04: /usr/bin/g++-9 Release Threads	32m 1s
ubuntu-20.04: /usr/bin/g++-9 Release OneTBB	1m 59s
ubuntu-20.04: /usr/bin/g++-9 Release PaRSEC	1m 44s
macos-latest: clang++ Debug Threads	18m 25s
macos-latest: clang++ Debug OneTBB	3m 40s
macos-latest: clang++ Debug PaRSEC	2m 37s
ubuntu-20.04: /usr/bin/g++-9 Debug Threads	31m 43s
ubuntu-20.04: /usr/bin/g++-9 Debug OneTBB	1m 54s
ubuntu-20.04: /usr/bin/g++-9 Debug PaRSEC	1m 50s
	2h 16m 30s

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