Hi, 2011/12/2 Martin Hamant <[email protected]>: > > > Le 01/12/2011 19:24, David Baelde a écrit : > >> Hi guys, >> >> I listened to the two files. Sometimes I feel like I can hear some >> artifacts, but it's really slight; I'm not sure I could tell them >> apart in a blind test. Anyway, I'm no expert in hearing compression >> artifacts. > > I'm no expert either, but I have good hears (I don't say you haven't ;) ) > and I can tell for sure the sound is affected, much more as it should be for > this bitrate. > But see below I have done more tests. > > >> >> I'm not sure where to go from here. It would be interesting to check >> what parameters really end up being passed to liblame with the two >> tools. Sometimes, an interface might do some adjustment on parameters >> to make things sound better. > > >> >> Otherwise, if you don't want to dig into the source code of audacity >> (for liquidsoap, you can ask us the details) you can just try to raise >> a little bit the quality settings. >> > The thing is, even exporting with lame parameter -q9 ("Disables almost all > algorithms including psy-model. Poor quality."), I can't get it as worse as > the LS's one. > I would like to find a parameter in lame that would reproduce the noise I > can hear, but I can't find one to make it worse :D > > More seriously, I done some more testing. I tested a compress to 96Kbit/s > and compared it with the 128Kbit/s from liquidsoap. The conclusion is the > artefacts I hear in the 96k one is for sure not the kind of the > artefacts/noise in LS one. > the 96k bitrate raise some "birdies" in the sound when the LS file get some > "noise"/tremolo in low frequencies. HF are not so much affected. > > For me, there is little chance that this quality issue to be related to > libmp3lame. So the question would be, may LS apply some kind of processing > on the file before or after the encoding step ?
No we don't. Actually, since you are using FLAC as input, you can assume that PCM data fed to lame is the exact original data. However, I'v had a look at ocaml-lame parameters and I think this guy, which we do not use, might be a good candidate: http://liquidsoap.fm/modules/ocaml-lame/Lame.html#VALset_quality I'll patch our HG source to add support for it ASAP and let you know so you can run your tests against it. Romain ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Savonet-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/savonet-users
