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Suggest ~160kbps VBR setting.
guidryp
post Mar 30 2002, 19:27
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Hi,

Looking at the suggested settings/presets I am dismayed at the lack of a VBR setting that operates at a lower bit-rate.

There is APS standard, which on my music easily averages over 200Kbps. In fact my latest Rush albums are averaging over 220Kbps.

I can see noisy metal taking over 220kbps, but a song like Rush-Nobody's Hero taking 230Kbps?

For me, it calls into question the validity of the VBR model if the answer to lower than 230KBps encoding is to use the ABR/CBR settings.

ABR doesn't seem much better than CBR after watching it encode 90+ % of its samples at the target rate.

Surely a VBR setting can be cooked up that can encode the above track at ~160kbps in VBR and still sound better than 160 ABR.

PS - I want to use this setting in my compact Flash based portable, in my car etc. My max space average is 160Kbps do to the size of the portable memory. But I want the best quality in that space.

Peter
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JohnV
post Mar 31 2002, 21:05
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Yes, VBR would use more bits for harder sections, but that kind of Lame vbr mode which would give average 160kbps with metal is going to fall too low pretty often and will introduce clear distortion, especially if -Y (ignoring of SFB21 noise shaping) or very high --ns-sfb21 value (high masking for SFB21) is not used. If -Y is not used, you would have to compensate the high amount of bits given to all SFBs because of the over 16khz content (due to SFB21 lack of scalefactor) by increasing the overall masking threshold (lowering overall resolution with higher -v switch) significantly, which would lead to overall lower quality. So there's no way to get good high freq response and low average bitrate with MP3 VBR. This is a problem in MP3 technical details (lack of scalefactor for SFB21), and it can't be fixed.

Of course if there was an easy way to create a working decent quality lowbitrate vbr-mode, it would have been done and commonly in use. But sadly this is not the case at the moment. Don't know if Dibrom has some tricks in his pocket..?

Also with higher bitrate VBR it's not always only difficult sections that get 320 or 256kbps frames especially with metal. Metal music can have quite high masking tendency for low/mid bitrates, but because lots of high frequencies may have to be coded, the overall bitrate will skyrcoket again because of SFB21 issue. It directly means that simply because of loud over 16kHz content, lower frequency content may have to be coded with much higher resolution than would be otherwise necessary, it's grazy, but blame the missing scalefactor for SFB21...


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Juha Laaksonheimo
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Posts in this topic
- guidryp   Suggest ~160kbps VBR setting.   Mar 30 2002, 19:27
- - SometimesWarrior   Take a look at this thread for some info on how to...   Mar 30 2002, 21:06
- - Negative Zero   You could also try the --r3mix switch, which resul...   Mar 30 2002, 21:51
- - JohnV   QUOTE Originally posted by Negative Zero You coul...   Mar 31 2002, 01:53
- - mithrandir   Why are there still so many --r3mix followers? It ...   Mar 31 2002, 02:57
- - guidryp   QUOTE Originally posted by mithrandir Although I...   Mar 31 2002, 05:59
- - mithrandir   I say alt-preset extreme -Y creates files with a r...   Mar 31 2002, 08:11
- - JohnV   QUOTE Originally posted by guidryp I am seeking a...   Mar 31 2002, 12:12
- - guidryp   QUOTE Originally posted by mithrandir If you nee...   Mar 31 2002, 18:16
- - guidryp   QUOTE Originally posted by JohnV Well, I don't kn...   Mar 31 2002, 18:55
- - mithrandir   QUOTE Originally posted by guidryp The problem I ...   Mar 31 2002, 21:02
- - JohnV   Yes, VBR would use more bits for harder sections, ...   Mar 31 2002, 21:05
- - guidryp   QUOTE Originally posted by mithrandir make two ...   Mar 31 2002, 22:03
- - guidryp   QUOTE Originally posted by JohnV Yes, VBR would u...   Mar 31 2002, 22:21
- - JohnV   QUOTE Originally posted by guidryp Rush == Metal?...   Mar 31 2002, 22:49
- - guidryp   Well after a bit of testing, I am going with: --a...   Apr 2 2002, 05:36
- - Dibrom   QUOTE Originally posted by guidryp Well after a b...   Apr 2 2002, 10:03
- - guidryp   For whatever reason, I remember --lowpass 16 using...   Apr 2 2002, 14:24
- - JohnV   QUOTE Originally posted by guidryp For whatever r...   Apr 2 2002, 14:35
- - guidryp   QUOTE Originally posted by JohnV Seems that you d...   Apr 2 2002, 15:02
- - indybrett   Thought I might try this for myself. Without goin...   Apr 2 2002, 15:34
- - JohnV   QUOTE Originally posted by guidryp I had read th...   Apr 2 2002, 16:48
- - fewtch   Just my opinion, but if you're gonna do an abrupt ...   Apr 2 2002, 17:05
- - guidryp   QUOTE Originally posted by fewtch Just my opinion...   Apr 2 2002, 17:19
- - scoper   Reading the suggestions of Dibrom and others regar...   Apr 2 2002, 17:25
- - guidryp   QUOTE Originally posted by JohnV Still I think ...   Apr 2 2002, 17:26
- - Dibrom   QUOTE Originally posted by scoper Reading the sug...   Apr 2 2002, 22:12
- - pacohaas   I ripped some complete albums and did some encodin...   Apr 3 2002, 04:25
- - guidryp   Holy Smokes! You ripped 7 albums 5 times just to ...   Apr 3 2002, 12:51
- - Amadeus93   QUOTE Originally posted by pacohaas 1. -b32 hardl...   Apr 3 2002, 13:43
- - JohnV   QUOTE Originally posted by pacohaas 2. While -Y d...   Apr 3 2002, 15:59
- - pacohaas   QUOTE Originally posted by JohnV Again... -Y is n...   Apr 5 2002, 03:08
- - pacohaas   which brings me to yet another idea that I've been...   Apr 5 2002, 03:13


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