lame3995m - a constraint vbr variant
Reply #16 – 2013-12-14 20:08:47
... A bitrate can be safely dropped on easy parts. If an encoder is constrained for a lower limit of bitrate then there will be less possiblities to save these bits and donate them to difficult parts. ... This is wrong as far as my Lame extension is concerned. I always take care of having available data space at the maximum which is possible within the possibilities of the mp3 format. This is one of the basic design principles which is in favor of my extension. Other than that there's much truth in what you wrote, and I hope I have never risen too much hope that my extension gives a great progress compared to standard Lame. In the bitrate range up to that of standard -V0 chance of getting better results than that of the standard Lame version is very low. It's not zero however as there are samples where the difference is ABXable (eig, lead-voice). And in terms of increased bitrate it comes at a cost which is next to nothing. In terms of encoding speed cost is not negligible, but when it's essential, that is when you're encoding a lot of tracks, the cost factor is lower than 5 when encoding with a good multicore system and a software like foobar which makes good use of it. On my i7-3930K system it's less than 2. To me the main advantage comes from the fact that Lame development of recent years focussed on VBR. My extension allows these improvements to be combined with very high bitrate settings which extend the VBR average bitrate range beyond that of -V0. Of course this is usually overkill, but for those who don't care about that but want a very good quality even in extreme cases this can be considered an attractive alternative to CBR 320 or very high bitrate ABR. And again, there are samples where you can ABX the difference towards standard Lame -V0 (harp40_1, herding_calls, trumpet_myPrince).