View Issue Details
|ID||Category||Date Submitted||Last Update|
|0007127||other||2016-11-17 19:47||2016-11-20 18:15|
|Reproducibility||have not tried|
|Fixed in Version|
|Summary||0007127: Ardour resampling is 8 times slower than SoX|
|Description||Accidentally I did a resampling benchmark. The source is a 24-bit stereo WAV at 44.1, I wanted to resample it to 48 kHz. However Ardours seems to do this very slow.|
I tried using sox for this, and I found out Ardour is actually 8 times slower at this.
SoX - 8.5 seconds.
Ardour - 65 seconds.
This is a dramatic difference.
Can something be done to speed things up for Ardour?
|Steps To Reproduce||1. Prepare yourself a big WAV file using a differnt sampling rate than your normal Ardour sessions.|
2. Use a sox command to convert it to your Ardour session's sampling rate (for example 48 kHz)
time sox input.wav -r 48000 output.wav
This will also measure the execution time
3. Prepare a stopwatch.
4. Drag the input file into the Ardour session and start the stopwatch.
5. Stop the stopwatch when Ardour finishes the import.
6. Compare the two times.
|Additional Information||This is the sox command I originally used:|
sox -V6 input.wav -r 48000 output.wav
The -V6 makes SoX very verbose.
|Tags||No tags attached.|
Can you also compare against `sndfile-resample` (ardour uses libSRC)
on import Ardour also demuxes and reformats the file, but the overhead of that is probably small.
Are you comparing SRC methods of similar quality? Last time I tried sox default SRC settings it was quick but the result didn't sound as good to me as the highest quality setting in sndfile-resample.
After further testing, I suspect that my opinion of sox vs libsamplerate SRC is subjective preference. SoX default src setting appears to use a steeper anti-alias filter than -c 0 setting in libsamplerate*. The libsamplerate SRC still sounds slightly better to my ears, but the SoX SRC is impressively quick.
*Tested by recording a 24kHz sine wave to a 96kHz file, downsampling to 48kHz using sox and libsamplerate, and comparing the spectrum plot of the result in jaaa. The libsamplerate version shows a residual 24kHz signal at -116dB, but sox version shows none at all.
|2016-11-17 19:47||unfa||New Issue|
|2016-11-17 21:08||x42||Note Added: 0018984|
|2016-11-19 13:21||jrigg||Note Added: 0018989|
|2016-11-19 13:51||x42||Note Added: 0018990|
|2016-11-20 17:30||jrigg||Note Edited: 0018989||View Revisions|
|2016-11-20 18:10||jrigg||Note Added: 0019012|
|2016-11-20 18:15||jrigg||Note Edited: 0019012||View Revisions|