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128 kbps DAB vs AAC+ & MP3
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I saw someone on Digital Spy effectively try and suggest that 128 kbps on
DAB sounded better than 112 kbps MP3 a couple of weeks ago, so I decided to
encode a track at 112 kbps MP3 to let him download it. Anyway after an
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Was that the same thread I posted too? I used 96kbps mp3 which sounded
better than anything on DAB!
[snip]
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exchange of a couple of messages he asked me to encode something that I had
in my CD collection that he'd recorded off DAB so that he could compare. In
the end we settled on "Take Your Mama" by the Scissor Sisters, simply
because he had a recording of it and I had it in my CD collection, i.e. not
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You cant compare codecs that way. Unless you run your cd version
through a the same On Air processor they used on that DAB broadcast.
The DAB version probably went through most likely goes through AGC, Stereo
enhancement, EQ, Multiband compression, multiband limiting, emphais,
HF Limiting and a clipper to finish it off.
From the first snare hit and 1.5 seconds
RMS level of the cd version is -15.4 db
RMS level of the DAB version is -12.4 db (louder)
The processor has squased the life out of the music - and this has nothing
to
do with DAB - same thing happens on FM. You cant compare codecs like
this.
Jan Holm
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because it was particularly difficult to encode or anything like that.
So I encoded it to 112 kbps, and then, even though I didn't have a sound
card, I was confident that 96 kbps MP3 would sound better than 128 kbps DAB,
so I encoded to 96k MP3 as well. Then, as he has always supported the
current DAB system, I thought I'd encode at a few AAC+ bit rates to show how
inefficient MP2 is.
So I've ended up with the following versions:
sisters.mp2 (the 128 kbps DAB version)
take_your_mama_80k_aac+.m4a
take_your_mama_64k_aac+.m4a
take_your_mama_48k_aac+.m4a
take_your_mama_32k_aac+.m4a
take_your_mama_24k_aac+.m4a
take_your_mama_96k.mp3
take_your_mama_112k.mp3
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I can hear a difference even on my tinny little lap top speakers.
The 112k mp3 version defiantly does have a clearer treble.
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The only one without a high frequency response is the DAB file!
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Even the 24k AAC+ stream seems to sound better than the MP2 stream, but
that may be partly due to loss of stereo image on the MP2 version.
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I don't think the loss of the stereo image would make it sound worse, or not
much worse anyway.
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Richard E.
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Which encoder did you use for each files and which parmaters for each
files ?
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For AAC+ I used Nero's MPEG-4 AAC/AAC+ command line encoder using:
-cbr xx000
For MP3 I used Lame 3.97b2 and:
-b xxx -m j
replace x's with bit rate value.
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And for MP2 ?
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Someone recorded it off the radio.
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So you compare apple and eggs !!
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Where's the high frequencies on the DAB sample?
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You don't encode the SAME source.
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Where's the high frequencies on the DAB sample?
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Does the source have it ?
You are unable to reply to this question because you didn't get the
source JUST before the audio encoder everything else is pure
speculation.
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I obviously own the CD or I wouldn't have been able to encode the AAC+ and
MP3 files, and they have the high frequencies, so where've they gone on the
DAB sample?
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the sound processing before the audio encoder ?
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If was interested in the music (which I'm not) it would be interesting
to encode it at 128kbps mp2 48kHz to hear the result. I'm sure Steve
can do this - or if he makes a lossless version available I'll encode
it. You can then comment on what you hear.
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I thought it would. And I was surprised at how low AAC+ could go while still
sounding better than DAB.
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Cheers,
David.
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Croiset, I thought you'd now be in favour of AAC+ considering that you're a
big supporter of the DAB system and France is adopting DAB with AAC+?
Come on, it's time to stop supporting the terrible MP2 codec - you make a
fool of yourself every time you express support for the 1980s codec.
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Nicolas Croiset VDL
http://www.vdl.fr/
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How. What model of Radio, which soundcard, was it a digital transfer,
how did become an mp2 file.
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Sound card? Digital transfer? Become an MP2 file? Do you not understand any
of this?
It is obviously the raw MP2 bistream of a digital radio station (in this
case it was a station on DAB) recorded directly to memory.
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Which software grabs mp2 and saves directly without doing another mp2
encoding ?
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All DVB-T and DVB-S PC cards and USB receivers, and on DAB the Psion
Wavefinder, The Bug, the Evoke-3 and any other DAB receivers that can record
to an SD card.
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One little exception to that is the otherwise interesting Genus SLM
pocket radio -- I have an email from them saying that it doesn't
record in mp2.
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DVB-T and DVB-S PC cards record the bitstream of TV channels directly to
hard drives as well, which is what I use to record TV programmes.
This is hardly a rare thing, and recording the raw MP2 audio or MPEG-2 video
directly to a hard drive obviously requires the *least* processing on a PC,
because you just store it as it is received, rather than needlessly decode
then re-encode.
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Jan Holm
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Who on earth would choose to encode recordings to 128 kbps MP2 unless they
were stark raving mad or just incredibly thick?
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Jan Holm
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Nicolas Croiset VDL
http://www.vdl.fr/
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which should be self-explanatory from the file names what they are.
I've put them all in a Zip file which can be downloaded from here:
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Can you share a lossless version too please?
Cheers,
David.
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One thing to say about the DAB version: the high frequencies seem to have
vanished, and despite the fact that this recording is *nowhere near* the
worst that 128 kbps DAB can sound (remember that the DAB supporter was
trying to suggest that this was relatively good!), when you compare it to
other versions it's a good example of why they should never have been
allowed 128 kbps MP2 to be used.
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