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Topic: MP3 Listening Test at 128 kbps (Read 208285 times) previous topic - next topic
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MP3 Listening Test at 128 kbps

Reply #250 –
Thank you for fast reply and organization of test that never conducted.
Never mind.

MP3 Listening Test at 128 kbps

Reply #251 –
Quote
Thank you for fast reply and organization of test that never conducted.
Never mind.
Even if I too deplore this thread and any public HA listening test was entirely becalmed, there's no need to get this bitter.  Nobody stops you from organizing one of your own, in all its complexities, after all.

MP3 Listening Test at 128 kbps

Reply #252 –
I have obtained one top secret information.....
Sebastian will most probably start test today

MP3 Listening Test at 128 kbps

Reply #253 –
Hey guys, just a small status update:

1. First of all, it's not easy to organize listening tests and I have been pretty busy with private stuff lately.

2. A new LAME version was released on RareWares yesterday. It doesn't matter if it adds changes that affect audio quality because people usually only look at the version and then ask "is 3.98.x now better than 3.98?", "why didn't you test 3.98.x"? At least the known bugs should be fixed so I don't expect a new build to pop up soon so that I can take 3.98.2 for the test.

3. I am currently having problems with hosting the samples. Roberto was kind enough to host them for me in the past but I was unable to reach him and I cannot host them myself because of the copyright situation in Germany.

I don't think I will be able to make it today because I just got home from work, but I will really do my best to start the test this week. Thanks to everyone who submitted samples by the way.

Edit: IgorC, For some reason I wasn't notified that you replied to my thread that is why I didn't even notice. Re-subscribed now - hopefully it works.

MP3 Listening Test at 128 kbps

Reply #254 –
Quote from: Sebastian Mares on
I am currently having problems with hosting the samples. Roberto was kind enough to host them for me in the past but I was unable to reach him and I cannot host them myself because of the copyright situation in Germany.
I could do that for you.  Straight FTP though, no torrents.

MP3 Listening Test at 128 kbps

Reply #256 –
Quote from: Sebastian Mares on
Thanks! What kind of connection do you have? Any traffic limits?
I happen to work for an ISP, so I have my own little private web/FTP/mail server hooked up to 2 redundant Gbit uplinks in a western European data centre.  No traffic limits of any kind for a couple of tens of GBytes of sound files to become too much
So availability and performance shouldn't be any problem whatsoever.

MP3 Listening Test at 128 kbps

Reply #257 –
Just finished encoding all samples - finally. One of the samples produces 214 kbps with LAME 3.98.2 -V5.7. LAME 3.97 -V5 --vbr-new reaches 198 kbps. iTunes on the other hand set to 112 kbps VBR highest setting reaches only 122 kbps.

Would you count this as a big problem?

MP3 Listening Test at 128 kbps

Reply #259 –
FhG produces also 212 kbps for this sample.

The other samples are also quite high. I will post a bitrate table... Just give me some time, it's after midnight and my brain and body only work at 50%.

MP3 Listening Test at 128 kbps

Reply #260 –
Code: [Select]
             LAME 3.97    LAME 3.98.2    iTunes    FhG    Helix    Low Anchor
Sample 01    97           107            115       119    114      128
Sample 02    126          149            113       121    110      128
Sample 03    138          143            119       139    126      128
Sample 04    149          139            116       140    151      128
Sample 05    146          138            121       144    149      128
Sample 06    149          142            120       149    151      128
Sample 07    95           109            118       134    131      128
Sample 08    147          136            113       128    137      128
Sample 09    109          118            115       128    97       128
Sample 10    158          152            120       147    152      128
Sample 11    148          145            117       133    117      128
Sample 12    194          214            122       212    227      128
Sample 13    132          145            124       150    142      128
Sample 14    159          156            124       163    173      128

Seems that iTunes is only very restrictive. Wondering if I should simply set it to 128 kbps instead of 112 kbps.

MP3 Listening Test at 128 kbps

Reply #261 –
Have you looked at a histogram?

Anyway, I don't want to repeat the discussion we had about this last year, but I haven't changed my opinion about it.  iTunes should be configured at 128, especially since you don't expect it to do well anyhow.  Might as well not leave any wiggle room like the previous test did.

MP3 Listening Test at 128 kbps

Reply #262 –
Hmm, damn... Maybe they changed the MP3 encoder with iTunes 8. Does anyone have the old iTunes 7? I would install it on a VM and compare the bitrates it produces vs. iTunes 8. If iTunes 7 makes higher bitrates at 112 kbps, I will definitely go with 128 in iTunes 8. Otherwise, is it fair to adjust the encoder settings based on short samples only if otherwise 112 VBR produces an average of 128 kbps when fed with whole tracks?

Regarding the other encoders, if you "ignore" iTunes, I would say that the bitrate fluctuations of the other samples are OK (like for example Sample 02 where Helix allocated 110 kbps and LAME 3.98.2 149 kbps).

MP3 Listening Test at 128 kbps

Reply #263 –
Found iTunes 7.7 myself. 112 kbps produces 122 kbps and 128 kbps produces 141 kbps for that specific sample.

The question is: should I choose 128 kbps for all iTunes samples even if 112 kbps is "nearer" to to the target bitrate of this test according to Alex B's findings (when encoding full tracks)?

MP3 Listening Test at 128 kbps

Reply #264 –
Hold on a moment.

I am just encoding my various and classical sets with iTunes 8. Probably iTunes has changed again. Maybe the increased VBR bitrates in the latest iTunes 7 builds were not intentional after all. Before that previous change 128 kbps VBR produced a suitable average bitrate. I'll post the results in an hour or so.

P.S. Sorry, that I have not been available for a while. I have had busy times lately. Looks like you had to make the final sample selections without lots of help from others. Are you going to keep the list secret until the test is out?

MP3 Listening Test at 128 kbps

Reply #265 –
I don't think bitrates have changed. With iTunes 7.7 (last 7 build) the bitrate is identical to iTunes 8. The problem is that iTunes seems to be very restrictive with the bitrate allocation. A quick look with EncSpot shows that 80% of the frames are encoded with the target bitrate.

MP3 Listening Test at 128 kbps

Reply #266 –
You are right, the bitrate behavior has not changed. In fact, the resulting files are bit identical. I checked that with foobar's bitcompare tool. Maybe I misunderstood what you meant.

Here is an excerpt from my previous bitrate test report:

Quote from: Alex B on
Apparently iTunes has changed radically since my last test. Back then the 128 kbps VBR setting was suitable, but the 7.7 version uses bitrates in a more relaxed way and the 128 kbps VBR setting produces higher bitrates than before. Fortunately the 112 kbps VBR setting appears to be suitable for our test.

Summary







IMHO, it would not be acceptable to use a setting that produces 161 kbps on average with various rock & pop music.

Quote from: Sebastian Mares on
I don't think bitrates have changed. With iTunes 7.7 (last 7 build) the bitrate is identical to iTunes 8. The problem is that iTunes seems to be very restrictive with the bitrate allocation. A quick look with EncSpot shows that 80% of the frames are encoded with the target bitrate.

In my test the new iTunes 112 VBR produced bitrates from 114 to 168 kbps. AFAICS, its encoder is not very restrictive anymore (except that its minimum bitrate is strictly restricted to the defined setting.)

I wonder if iTunes is doing something funny when the encoded file has a short duration. Have you compared a sample and its complete source track after encoding?

Also, just to make sure we are using the same settings, here is what I have set for 112 kbps VBR:

MP3 Listening Test at 128 kbps

Reply #267 –
Quote from: Alex B on
In my test the new iTunes 112 VBR produced bitrates from 114 to 168 kbps. AFAICS, its encoder is not very restrictive anymore (except that its minimum bitrate is strictly restricted to the defined setting.)


What I mean with restrictive is that when you have a look at the MP3 files produced by LAME or FhG with EncSpot, you will see that there is a quite even distribution of frames between let's say 64 kbps and 320 kbps. When you look at iTunes files, you see that about 80% of the frames are coded at 112 or 128 kbps (depending on what bitrate you set iTunes to encode to) and only 20% of the frames have other bitrates. That is why with my samples (most of them if you look at the table), iTunes has the lowest bitrate (you don't find a single sample with a bitrate higher than 130 kbps or lower than 112 kbps when the target bitrate is 112 kbps - the latter having the explanation that the bitrate you set in iTunes is also handled as min bitrate for VBR coding).

Quote from: Alex B on
I wonder if iTunes is doing something funny when the encoded file has a short duration. Have you compared a sample and its complete source track after encoding?


I will encode one or two files when I am at home in a few hours.

Quote from: Alex B on
Also, just to make sure we are using the same settings, here is what I have set for 112 kbps VBR:



Yes, same settings here.

Now the big question is whether or not to leave everything as-is. In the end, all other coders (except for low anchor that is CBR) allocate high bitrates for the specific sample we're talking about here. That is why I would say that if iTunes thinks it can handle the file fine with 122 kbps and in fact it doesn't, then its psy / VBR model is to blame.

MP3 Listening Test at 128 kbps

Reply #268 –
Quote from: Sebastian Mares on
When you look at iTunes files, you see that about 80% of the frames are coded at 112 or 128 kbps (depending on what bitrate you set iTunes to encode to) and only 20% of the frames have other bitrates.
That is odd. I don't see it happening with my test tracks. Only the files with the lowest bitrate are like you said. The complex files show more bitrate variation. Though apparently 112 VBR has a 224 kbps max bitrate limit and 128 VBR 256 kbps max bitrate limit (I hadn't noticed the upper limit before)

Here's what EncSpot says about the three tracks that produced the highest bitrates @ 112 VBR:

Code: [Select]
[b]Kraftwerk[/b]

Bitrates:
----------------------------------------------------
112     ||||||||||||||||||||||||||||||||||||||         31.2%
128     ||||||                                          5.4%
160     ||||||||||||||||||||||                         18.4%
192     ||||||||||||||||                               12.9%
224     ||||||||||||||||||||||||||||||||||||||||       32.1%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 168
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 10045
ID3v2 Size          : 2146
First Frame Pos     : 2146
Length              : 00:04:22
Max. Reservoir      : 167
Av. Reservoir       : 72
Emphasis            : none
Scalefac            : 9.9%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.1 ]--[ [url=http://www.guerillasoft.com]http://www.guerillasoft.com[/url] ]--


[b]Faithless[/b]

Bitrates:
----------------------------------------------------
112     ||||||||||||||||||||||||||||||||||||||||       25.7%
128     ||||||||||||||||||                             11.6%
160     ||||||||||||||||||||||||||||||||||||           23.6%
192     |||||||||||||||||||||||||||||||                20.5%
224     ||||||||||||||||||||||||||||                   18.6%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 162
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 8588
ID3v2 Size          : 2140
First Frame Pos     : 2140
Length              : 00:03:44
Max. Reservoir      : 246
Av. Reservoir       : 76
Emphasis            : none
Scalefac            : 5.7%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.1 ]--[ [url=http://www.guerillasoft.com]http://www.guerillasoft.com[/url] ]--


[b]Yello[/b]

Bitrates:
----------------------------------------------------
112     ||||||||||||||||||||||||||||||||||||||||       34.1%
128     ||||||||||                                      8.7%
160     |||||||||||||||||||                            17.0%
192     ||||||||||||||||||                             15.4%
224     |||||||||||||||||||||||||||||                  24.8%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 161
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 7220
ID3v2 Size          : 2131
First Frame Pos     : 2131
Length              : 00:03:08
Max. Reservoir      : 345
Av. Reservoir       : 76
Emphasis            : none
Scalefac            : 4.7%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.1 ]--[ [url=http://www.guerillasoft.com]http://www.guerillasoft.com[/url] ]--
...and before anyone complains: The files are encoded with iTunes. EncSpot's guess is incorrect.

MP3 Listening Test at 128 kbps

Reply #269 –
Just did a quick test with some samples and there is no difference between full tracks and samples. If the sample had let's say 88% 112 kbps frames, the full track also had around 80% 112 kbps frames. Wondering why...

MP3 Listening Test at 128 kbps

Reply #270 –
I created samples of the three high bitrate tracks in my previous post:

Code: [Select]
[b]Kraftwerk (sample)[/b]

Bitrates:
----------------------------------------------------
112     |||||||||||||||||||||||||||                    25.2%
128     |||||                                           5.3%
160     ||||||||||||||||||||                           18.9%
192     |||||||||||||||                                14.0%
224     ||||||||||||||||||||||||||||||||||||||||       36.5%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 174
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 1142
ID3v2 Size          : 2149
First Frame Pos     : 2149
Length              : 00:00:29
Max. Reservoir      : 204
Av. Reservoir       : 78
Emphasis            : none
Scalefac            : 12.1%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.1 ]--[ [url=http://www.guerillasoft.com]http://www.guerillasoft.com[/url] ]--


[b]Faithless (sample)[/b]

Bitrates:
----------------------------------------------------
112     ||||||||||||||||||||||||||||||||||||||||       25.1%
128     ||||||||||||||||||||||                         13.9%
160     |||||||||||||||||||||||||||||||||||||          23.4%
192     |||||||||||||||||||||||||||||||||||||          23.3%
224     ||||||||||||||||||||||                         14.2%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 160
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 1143
ID3v2 Size          : 2143
First Frame Pos     : 2143
Length              : 00:00:29
Max. Reservoir      : 186
Av. Reservoir       : 77
Emphasis            : none
Scalefac            : 5.1%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.1 ]--[ [url=http://www.guerillasoft.com]http://www.guerillasoft.com[/url] ]--


[b]Yello (sample)[/b]

Bitrates:
----------------------------------------------------
112     ||||||||||||||||||||||||||||||||||||||||       42.1%
128     |||||||||||||                                  14.4%
160     |||||||||||||||||||||||                        25.0%
192     ||||||||||                                     11.3%
224     ||||||                                          7.2%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 143
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 1146
ID3v2 Size          : 2134
First Frame Pos     : 2134
Length              : 00:00:29
Max. Reservoir      : 186
Av. Reservoir       : 71
Emphasis            : none
Scalefac            : 5.6%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.1 ]--[ [url=http://www.guerillasoft.com]http://www.guerillasoft.com[/url] ]--

I think they are fine when I compare about the same passages in the complete encoded tracks.

The big question is why your "hard to encode" samples do not produce higher bitrates if mine do.

You can download my samples from here: http://rapidshare.com/files/150063026/set_...ate_samples.rar (10.8 MB)

MP3 Listening Test at 128 kbps

Reply #271 –
Could you please encode fatboy with iTunes and tell me what the outcome is? I really hope it is 122 kbps - otherwise, there is something really wrong with my PC.

If that produces a low bitrate while other tracks you tested produce a high bitrate it means that iTunes' VBR implementation thinks that the 122 kbps should be sufficient and I see no problem then. If the sample sounds worse, than LAME which uses 200 kbps, then we can say hard luck because iTunes could have increased the bitrate if it felt the need for it.

MP3 Listening Test at 128 kbps

Reply #272 –
Done.

Code: [Select]
[b]Fatboy_30sec[/b]

Bitrates:
----------------------------------------------------
112     |||||||||||                                    17.8%
128     ||                                              4.4%
160     |||||                                           8.5%
192     |||||                                           8.4%
224     ||||||||||||||||||||||||||||||||||||||||       60.9%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 191
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 1122
ID3v2 Size          : 2123
First Frame Pos     : 2123
Length              : 00:00:29
Max. Reservoir      : 428
Av. Reservoir       : 65
Emphasis            : none
Scalefac            : 5.6%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.1 ]--[ [url=http://www.guerillasoft.com]http://www.guerillasoft.com[/url] ]--
The encoded file is here: http://rapidshare.com/files/150073489/fatboy_30sec.rar

You must feel like  or maybe  ...

Ever called Apple's support? 

MP3 Listening Test at 128 kbps

Reply #273 –
WTF?! This is impossible... I decoded that file with fb2k to WAV. Then I added it to the iTunes library, configured the MP3 encoder, right clicked on the file and told it to convert the file to MP3. Then I took both fb2k and EncSpot 2.2 (that castrated Pro version) and checked the bitrate: 122 kbps.

Edit: The really funny thing is that the test with iTunes 7.7 which I performed today was with a different machine.

MP3 Listening Test at 128 kbps

Reply #274 –
Naturally I could help if your iTunes really has a problem that can't be quickly solved. It would take only a few minutes to encode the sample set.

EDIT

What is your iTunes build version? I have 8.0.0.35.