Re: [MP3 ENCODER] Mp3 encoders quality tests
George wrote: What do You recommend to me? Use the in_mp3.dll of v2.22? What about doing a mp3 decoder quality test too ? :-) That in_mp3.dll is AFAIK fraunhofer based and fraunhofer is touted to be one of the best ( ?? ) Did you think about doing the decoding yourselves and distributing only WAV sounds? That way you eliminate one variable at the listeners side ( they could for example use both winamp 2.22 and 2.61 and possibly get different results, but they would not report the used decoder; you don't require them to do that, do you ? ) I stand to use Winamp because is the most extended Mp3 player. But I accept ideas. What do you mean most extended ? You only need simple playback for the tests , no ? I think you should put more attention to the procedure of decoding and playback. david - Original Message - From: "David Balazic" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Monday, May 08, 2000 9:55 AM Subject: Re: [MP3 ENCODER] Mp3 encoders quality tests On the site you recommend WinAMP for the listening, while just recently a winamp bug was discussed on this list, which add corruptions during playback of mp3s ! The bug is present in winamp 2.62 ( latest as of this writing ), as reported on this list. david balazic George wrote: Hi to everyone! Just to say We've started the Mp3 Quality Tests. To continue the project We need volunteers to make auditions of Wav Mp3 files. If you're interested or know someone can be interested in, please go to http://www.hispamp3.com/bench/inde.htm or http://benchs.emp3.com . Everyone is welcomed. Thanks to all George "Mp3 Encoders Quality + Speed Stats" http://benchs.emp3.com -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ ) -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ ) -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ ) -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
Re: [MP3 ENCODER] Continuation of crippling wavs
| OdesÃlatel: Shawn Riley [EMAIL PROTECTED] | The album will be a mix of ballads rock songs. How do you guys suggest we do it? | | Note that we'd like there to have no percievable difference between the original effected sound in the studio. | I decided that the MP3 encoding should be bad for the following combinations- | 128kBit/sec - JStereo - 44.1kHz | 112kBit/sec - JStereo - 44.1kHz | 56kBit/sec - JStereo - 22.05kHz | I'd like to limit the subectivity of the word, "bad", to mean that it sounds particularly nasty unfaithful to people who are normally satisfied with sound quality at those described bitrates. | But I'd like it to still sound perceivably lossless for 320kBit/sec - Stereo, 'cause *I* would like to be able to make an MP3 of our stuff w/o having artifacts popping out everywhere. But that doesn't really matter quite so much 'cause I could always get a copy of the CD, mastered without the mangling. | | Shawn See archive of this maillist, few months ago I put here (GPL) method about psychoacoustics changes to sounds before ecoding and minimum bitrates (I reccomend 64kbit IS for 22kHz/full response, 64k JS for 10kHz or 56kbit ror reduced frequency response to 9-10k). REgars Jaroslav Lukesh -- -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
Re: [MP3 ENCODER] GA/GP
Hello, File size is easy enough to measure, but "sound quality" is not. It is purely subjective. VERY HARD to define on a computer. Are there any examples demonstrating (so I can _hear_ them) that a 'mathematical' comparison algo that tries to keep differences at a minimum doesn't work? I believe it, but I wonder how bad it really is :-) Regards, Mark -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
Re: [MP3 ENCODER] default high pass filtering
While I preety much agree with the rest of the post, I must comment on this one basis. On Tue, 9 May 2000, Gabriel Bouvigne wrote: [snip] why a 14Hz high pass filter and not a 20Hz one: because the lowest tone produced by a true musical instrument is 16Hz (it's from organ). [snip] And the fastest math calculateable by a true computer (the human type, i.e. the orignal use of the word computer) is X operations per second, so lets limit these new fangled silicon computers to X operations per second. :) -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
Re: [MP3 ENCODER] default high pass filtering
Hello I would vote for a default 14Hz high pass filter, removable with the -k option. Why an high pass filter: *theorical minimum audible freq for humans is 20Hz (also very discutable) *most soundcards are unable to reproduce less than 20Hz frequencies *most speakers are unable to reproduce less than 19Hz freq *most (if not all) headphones are unable to reproduce such low freq (even if their specs tell they are) *ISO doc recommends an high pass filter At 5 Hz, IIRC. *even if it's a small part of the spectrum, it's still a few bits usable for other more critical parts. _very_ few. Every mdct sample is about 38 Hz wide, so you wouldn't even cut away the first (or zeroeth, whatever) sample. The reason ISO recommends highpass filtering is to cut away the DC portions, which mp3 can't directly represents (it is a combination of the 0'th and 575'th sample. The 575'th normally gets set to zero, especially if you're lowpass filtering). You get DC in a long block, if the sound contains some components 19 Hz. DC leads to high-frequency echoes. (Some kind of phantom image of the true sound at lower freqs). Dag dag, Segher -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
Re: [MP3 ENCODER] Mp3 encoders quality tests
Hi, David! What do You recommend to me? Use the in_mp3.dll of v2.22? What about doing a mp3 decoder quality test too ? :-) a Mp3 decoder quality? Maybe after the Mp3 Encoders quality tests... why not?:-) That in_mp3.dll is AFAIK fraunhofer based and fraunhofer is touted to be one of the best ( ?? ) yes... Fraunhofer seems to be the best. Did you think about doing the decoding yourselves and distributing only WAV sounds? That way you eliminate one variable at the listeners side ( they could for example use both winamp 2.22 and 2.61 and possibly get different results, but they would not report the used decoder; you don't require them to do that, do you ? ) If I distribute the Wav files the size of ZIP files in the server increases dramatically! You are agree to download 2MB but... 14Mb??? I think you is possible, but most of people doesn't agree with it. :-( I think I will require the decoder information in the reports and see If I can get any conclusion about differences between v2.22 and 2.62... Thank you for the idea! I stand to use Winamp because is the most extended Mp3 player. But I accept ideas. What do you mean most extended ? You only need simple playback for the tests , no ? I say Winamp is because EVERYBODY has winamp (or any version of it). The volunteers doesn't need to download any player. If I use simple playback increases the use of different decoders, making the test more imprecise, isn't? I can demand the decoder used and make benchmarks about the different decoders too, isn't? Please, remember every idea is welcomed :-) What you think is the best? i) Demand to use only determinated version of winamp (v2.22 or 2.62) ii) Let to use any decoder but reporting what are they using Id the answer is the first one... Must I use Winamp with the in_mp3.dll of fraunhofer (v2.22) ? I think you should put more attention to the procedure of decoding and playback. Yes... I accept my error. George --- Mp3 Encoders Quality + Speed Stats! http://benchs.emp3.com -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
[MP3 ENCODER] free format bitstreams and iso documentation
According to my ISO doc (section 2.4.2.3), for layer III, decoders are not required to support higher free format higher than 320kbps. So free format is not restricted to =320kbps. And decoders must support free format at least up to 320k. My ISO 13818-3 documentation : Section 2.4.2.3 "The decoder is not required to support bitrates higher than 256 kbit/s, 160 kbit/s, 160 kbit/s in respect to Layer I, II and III when in free format mode." And in 2.1.74 : "2.1.74 free format [audio]: Any bitrate other than the defined bitrates that is less than the maximum valid bitrate for each layer." So, there is a maximum bitrate for free format or my ISO documentation is diferent from the original ISO or there's a newer version of the doc. My ISO 13818-3 is from 11/11/99 , and have 634 kb (doc format). There is any document that modify the ISO 13818-3 ?? -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
