Quote from: jaro1 on 10 March, 2009, 06:00:44 AMHi, I know it's a little offtopic, but I wanted to ask lvqcl to something, because I suppose he knows SOX internal routines quiet good yet.I think bandpass knows them much more
Hi, I know it's a little offtopic, but I wanted to ask lvqcl to something, because I suppose he knows SOX internal routines quiet good yet.
May I suggest a configuration option to only resample sample rates that are not supported by the (ASIO) audio card in use? Perhaps ideally just by doubling the rate until a supported rate is found?Cheers,Adriaan.
May I suggest a configuration option to only resample sample rates that are not supported by the (ASIO) audio card in use? Perhaps ideally just by doubling the rate until a supported rate is found?
Quote from: a3aan on 11 March, 2009, 03:21:33 PMMay I suggest a configuration option to only resample sample rates that are not supported by the (ASIO) audio card in use? Perhaps ideally just by doubling the rate until a supported rate is found?I thought about it, but ~99% of files in my music library have sample rate 44.1 kHz, so if I were to use ASIO, I'd stick with resampling all to 44 I'll think about adding this feature.
Are you saying that if I choose 44.1 kHz as a target rate then 44.1 kHz files are being sent to the card untouched?
I wonder what are the difference and therefore ten different plugins to choose from? Regards
Sounds like something that can be done with a separate DSP filter and the resampler_entry (resampler.h) class could be useful. An ideal solution would have a configurable list of supported sample rates, then upsample to the nearest supported rate as necessary.
Uploaded hereGood quality, fast resampler (~2 times faster than PPHS Ultra, although ~2.5 times slower than regular PPHS). Minimum / intermediate / linear phase.Any comments?
My question is, what does those settings do?
QuoteMy question is, what does those settings do?http://sox.sourceforge.net/Docs/FAQ -- "What are the best 'rate' settings to resample a file and retain the highest quality?"
The simple quality selection described above provides settings that satisfy the needs of the vast majority of resampling tasks. Occasionally, however, it may be desirable to fine-tune the resampler's filter response; this can be achieved using over‐ ride options, as detailed in the following table: -M/-I/-L Phase response = minimum/intermediate/linear -s Steep filter (band-width = 99%) -a Allow aliasing/imaging above the pass-band -b 74-99.7 Any band-width % -p 0-100 Any phase response (0 = minimum, 25 = intermediate, 50 = linear, 100 = maximum) All resamplers use filters that can sometimes create `echo' (a.k.a. `ringing') artefacts with transient signals such as those that occur with `finger snaps' or other highly percussive sounds. Such artefacts are much more noticeable to the human ear if they occur before the transient (`pre-echo') than if they occur after it (`post-echo'). Note that frequency of any such artefacts is related to the smaller of the original and new sam‐ pling rates but that if this is at least 44.1kHz, then the arte‐ facts will lie outside the range of human hearing. A phase response setting may be used to control the distribution of any transient echo between `pre' and `post': with minimum phase, there is no pre-echo but the longest post-echo; with lin‐ ear phase, pre and post echo are in equal amounts (in signal terms, but not audibility terms); the intermediate phase setting attempts to find the best compromise by selecting a small length (and level) of pre-echo and a medium lengthed post-echo. Minimum, intermediate, or linear phase response is selected using the -M, -I, or -L option; a custom phase response can be created with the -p option. Note that phase responses between `linear' and `maximum' (greater than 50) are rarely useful. A resampler's band-width setting determines how much of the fre‐ quency content of the original signal (w.r.t. the original sam‐ ple rate when up-sampling, or the new sample rate when down-sam‐ pling) is preserved during conversion. The term `pass-band' is used to refer to all frequencies up to the band-width point (e.g. for 44.1kHz sampling rate, and a resampling band-width of 95%, the pass-band represents frequencies from 0Hz (D.C.) to circa 21kHz). Increasing the resampler's band-width results in a slower conversion and can increase transient echo artefacts (and vice versa). The -s `steep filter' option changes resampling band-width from the default 95% (based on the 3dB point), to 99%. The -b option allows the band-width to be set to any value in the range 74-99.7 %, but note that band-width values greater than 99% are not recommended for normal use as they can cause excessive tran‐ sient echo. If the -a option is given, then aliasing/imaging above the pass- band is allowed. For example, with 44.1kHz sampling rate, and a resampling band-width of 95%, this means that frequency content above 21kHz can be distorted; however, since this is above the pass-band (i.e. above the highest frequency of interest/audi‐ bility), this may not be a problem. The benefits of allowing aliasing/imaging are reduced processing time, and reduced (by almost half) transient echo artefacts.
Thank you for your great support, one last question, is my setup for it good?I use 4800hz, very best quality, disabled steep filter and allow aliasing, with a linear phaser option, is this optimal for aac music files?
I do not understand.... What about "allow aliasing"?
And what phase response may I use for better sound???