Originally posted by guruboolez Frank, I have a question who haunt me for month... I encode my classical music in mpc for month, and I noticed immediatly after leaving mp3 than Musepack had I « strange » behaviour with some instruments. Piano don't need too much bitrate, with mp3, mpc or Vorbis. But a violon (not a critical instrument ) seems overrated by mppenc : +20% (200 on --standard ; 230-240 on extreme, etc...). Harpsichord, organ... the same thing (a bit less fororgan, but harpsichord is more problematic). With --alt-preset standard, I obtain 180 kb/s, and never reached 200 kb/s : mp3 is very cool for classical listener who don't like Metallica. But with Musepack, Mozart need as much bitrate as AC/DC with mp3 encoding :mad: I recently find a strange and forgotten instrument, called glass harmonica : an horrible and distorded sound !!! Brrr... With --alt-preset standard, an adagio (quiet but awfull music) need only 150 kb/s ! With mpc --standard : 250 kb/s !!!!Why distorded music (harpischord, baroque instruments) are needing so much bitrate, and why heavy metal don't ? Can you, or someone else, help me to understand this big differences ? Thanks a lot[sorry for my poor expression, and thanks again for your job]
Originally posted by Frank Klemm Harpsichord is one of most difficult to encode instruments.
Originally posted by Dibrom Futhermore, unless you've actually heard a problem with a codec like MPC for example (which you can provide samples and abx scores for), then why bother worrying about the bitrate it chooses on a particular sample? (given that the average bitrate overall is acceptable, which I believe it is)
Originally posted by spase first off, slower more quiet movements need more bitrate, because there is less volume in general, and thus less volume of noise and sound to cover up other sounds. as such, the encoder keeps more information about the sound, because more of it must be played back, as less of it is "covered up" by louder noise and sounds. (i hope you can understand this... and i hope i am correct at least partially on this)
as for mpc having higher bitrates, i believe you are correct in the idea that harpsichord, violin, and glass harmonica, while seemingly simple, are actually quite complex.
i personally have some tracks by blues traveller, in which john popper plays a normal harmonica, and when it is solo and lower volume, the mpc at standard --ltq fil jumps to over 230 kbps. later when it is "covered up" by drums and guitars and some audience noise, the bitrate drops down to about 190 kbps or so. i would believe this to be another example.
i hope i am correct in what i am saying, and i hope i have helped you with your answers, guru
Originally posted by guruboolez But as I often read it on this forum, space ALWAYS matters, no ?
Same thing for a violin concerto (or an orchestral work with a solo violin at the middle of the track) : +20-30% for a solo instrument, less for the 120 others playing at the same time.
Very well, spase. Thanks a lot for this answer.But don't blame me if I request again the opinion of the mpc developer : just for curiosity.
Originally posted by spase first off, slower more quiet movements need more bitrate, because there is less volume in general, and thus less volume of noise and sound to cover up other sounds.
Originally posted by unplugged So... Can we guess these are complicated situations for time domain based codecs? (like MPC)
I stop you : mp3 gives 150 kb/s and mpc 250 kb/sAnd I discover the problem before mppenc 1.00 (the 0.90 era). Frank Klemm has nothing to do with it
Last thing : it's glass harmonica, not organ,a very strange and rare instrument
Originally posted by jalonsom How about an hybrid codec that would decide to encode each frame either as subband or transform?
Originally posted by rjamorim That codec is called MPEG Audio Layer 3.
Maybe vorbis could implement subband in 2.0
Originally posted by Gecko Afaik "Subband Technology" is unfortunately patented by Philips. See here, number 8.