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Topic: MP3 Listening Test at 128 kbps (Read 209038 times) previous topic - next topic
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MP3 Listening Test at 128 kbps

Reply #277 –
Quote from: Alex B on
What is your iTunes build version? I have 8.0.0.35.


8.0.0.35 as well. I have a German version, BTW, but that shouldn't matter.

I take you use Windows not Mac OS? I'm on a German Vista Home Premium SP1. Wondering if my encoder is "broken" or yours since mine seems to always produce files that are very close to the target bitrate specified in the settings, while your is fluctuating a lot more. Also, 128 kbps produces nearly 128 kbps over my collection of files while your encoder reaches 160 kbps in average.

MP3 Listening Test at 128 kbps

Reply #278 –
I have English Windows XP Pro.

I tested the shorter fatboy:

Code: [Select]
[b]Fatboy_5sec[/b]

Bitrates:
----------------------------------------------------
112     ||||                                            9.7%
128                                                     2.1%
160     |                                               2.6%
192                                                     2.1%
224     ||||||||||||||||||||||||||||||||||||||||       83.1%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 208
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 195
ID3v2 Size          : 2122
First Frame Pos     : 2122
Length              : 00:00:05.0
Max. Reservoir      : 345
Av. Reservoir       : 59
Emphasis            : none
Scalefac            : 4.1%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

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

I checked also the 30s sample by calculating the bitrate from the file size and duration (I removed the ID3 tags with Mp3tag before checking the file size):

(701348 bytes x 8 bits per byte / 29.245 sec) x 1000 = 191.854 kbps

MP3 Listening Test at 128 kbps

Reply #279 –
This is really weird. I will encode at work tomorrow where I have an XP and Vista PC. Maybe the OS is to blame.

BTW, were iTunes 7 MP3s recognized as being encoded by FhG in EncSpot? I hope Apple didn't throw away their encoder in favor of FhG.

Edit: And BTW, you are testing with 112 kbps, correct?

MP3 Listening Test at 128 kbps

Reply #280 –
Quote from: Sebastian Mares on
Quote from: Alex B on

What is your iTunes build version? I have 8.0.0.35.
Wondering if my encoder is "broken" or yours since mine seems to always produce files that are very close to the target bitrate specified in the settings, while your is fluctuating a lot more. Also, 128 kbps produces nearly 128 kbps over my collection of files while your encoder reaches 160 kbps in average.

Please encode the three samples I uploaded to Rapishare so that we can compare the results.

EDIT

I think we need help from others. It would help if a few other HA members could encode these samples. The correcty settings can be checked  from the screenshot I posted earlier.

I have now only one PC with iTunes (a laptop). My HTPC is "under construction" and it may take a few days before it is usable again. Otherwise I could verify the results on a different PC and software setup.

MP3 Listening Test at 128 kbps

Reply #281 –
Faithless:
Code: [Select]
Bitrates:
----------------------------------------------------
112     ||||||||||||||||||||||||||||||||||||||||       77.1%
128     |||||                                          11.5%
160     ||||                                            8.9%
192                                                     1.8%
224                                                     0.5%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 120
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 1143
ID3v2 Size          : 2139
First Frame Pos     : 2139
Length              : 00:00:29
Max. Reservoir      : 115
Av. Reservoir       : 56
Emphasis            : none
Scalefac            : 3.7%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.2 ]--[ http://www.guerillasoft.com ]--


Kraftwerk:
Code: [Select]
Bitrates:
----------------------------------------------------
112     ||||||||||||||||||||||||||||||||||||||||       75.6%
128     |                                               3.4%
160     ||||||||||                                     19.7%
192                                                     0.4%
224                                                     0.8%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 123
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 1142
ID3v2 Size          : 2145
First Frame Pos     : 2145
Length              : 00:00:29
Max. Reservoir      : 156
Av. Reservoir       : 48
Emphasis            : none
Scalefac            : 2.8%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.2 ]--[ http://www.guerillasoft.com ]--


Yello:
Code: [Select]
Bitrates:
----------------------------------------------------
112     ||||||||||||||||||||||||||||||||||||||||       76.6%
128     ||||                                            9.0%
160     |||||                                          11.4%
192                                                     1.8%
224                                                     1.0%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 121
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 1146
ID3v2 Size          : 2130
First Frame Pos     : 2130
Length              : 00:00:29
Max. Reservoir      : 164
Av. Reservoir       : 58
Emphasis            : none
Scalefac            : 3.4%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.2 ]--[ http://www.guerillasoft.com ]--

MP3 Listening Test at 128 kbps

Reply #282 –
Quote from: Sebastian Mares on
BTW, were iTunes 7 MP3s recognized as being encoded by FhG in EncSpot? I hope Apple didn't throw away their encoder in favor of FhG.

Encspot has always done that.

Quote
Edit: And BTW, you are testing with 112 kbps, correct?

I have double and triple-checked the settings.

Also, my iTunes v.7.7.1.11 VBR112 and VBR128 results from August are identical with the new v.8 results.

Though I used this same PC back then. (I didn't want to install the bloated iTunes 7.7 on my other PC.)

This PC has a quite new OS installation. I installed a new hard drive and a vanilla XP Pro SP2 in April. The first iTunes version I installed was 7.6.2.9 (I have the installer still on the HD).

MP3 Listening Test at 128 kbps

Reply #283 –
Seriously, this is very strange. I hope other encoders (LAME, FhG, Xing) aren't affected by this.

I will test tomorrow morning under Vista and XP.

MP3 Listening Test at 128 kbps

Reply #284 –
This is a wild guess, but could it be possible that Apple has not changed the encoder after all? What if they have just loosened some hidden parameters, which might be stored in the registry. If they did a crappy job maybe a newer installer does not correctly overwrite the old parameters. It might be handling them as user settings which are carried over.

Have you had old iTunes versions installed on your OS? When I tested 7.4.2.9 about a year ago the bitrates were a lot lower.

MP3 Listening Test at 128 kbps

Reply #286 –
I tested fatboy_30sec and I got the same result as Sebastian (121kbps). Here is a result of bitrate fluctuation analysis:

iTunes: (larger image)


iTunes(Alex): (larger image)


LAME: (larger image)


The result of fatboy_30sec.mp3 by Alex seems to be close to the result by true VBR encoder like LAME. I'm very interested in how Alex obtained this mp3 file with iTunes...

MP3 Listening Test at 128 kbps

Reply #287 –
thanks for help

MP3 Listening Test at 128 kbps

Reply #288 –
Awesome! I just installed iTunes 8 on a fresh Vista Home Premium SP 1 and a fresh Windows XP Professional SP 3. Results for fatboy (30 seconds):

Vista: 122 kbps
XP: 191 kbps

So, I guess I will have to contact Apple support...

MP3 Listening Test at 128 kbps

Reply #289 –
That's really strange, but at least you found something. I was beginning to suspect that my SW configuration has something terribly wrong.

I wonder what kind of file a Mac iTunes would encode. Could anyone test this on a Mac and post a sample with details about the CPU and OS/SW versions?

EDIT

I converted the Fatboy 30 sec FLAC sample to Apple Lossless. It is available here:
http://rapidshare.com/files/150190105/fatboy_30sec_alac.zip

MP3 Listening Test at 128 kbps

Reply #290 –
I've tested fatboy_30sec on various environments with my Mac. Here are results:
OSX 10.5, Core 2 Duo, iTunes 8.0: 121 kbps
OSX 10.4, Core 2 Duo, iTunes 7.7.1: 121 kbps
OSX 10.4, PPC G5, iTunes 8.0: 122 kbps
OSX 10.5, PPC G4, iTunes 7.7.1: 192 kbps
OSX 10.5, PPC G4, iTunes 7.6: 192 kbps
OSX 10.4, PPC G4, iTunes 7.2: 192 kbps

Strange result. Different encoding algorithms are used according to CPU???

MP3 Listening Test at 128 kbps

Reply #292 –
A friend visited our office today. He had an old iTunes version installed on his Celeron M / XP Home SP2  laptop.

I encoded the fatboy sample with his iTunes 6.0.5.20. The version is well over two years old.

Code: [Select]
[b]Fatboy_30sec_iTunes_v.6.0.5.20[/b]

Bitrates:
----------------------------------------------------
112     |||||||||||                                    17.1%
128     ||                                              3.7%
160     |||||                                           8.6%
192     |||||                                           8.6%
224     ||||||||||||||||||||||||||||||||||||||||       61.9%
----------------------------------------------------

Type                : mpeg 1 layer III
Bitrate             : 192
Mode                : joint stereo
Frequency           : 44100 Hz
Frames              : 1122
ID3v2 Size          : 2102
First Frame Pos     : 2102
Length              : 00:00:29
Max. Reservoir      : 428
Av. Reservoir       : 68
Emphasis            : none
Scalefac            : 4.9%
Bad Last Frame      : no
Encoder             : FhG (fastenc)
Lame Header         : No

--[ EncSpot 2.1 ]--[ [url=http://www.guerillasoft.com]http://www.guerillasoft.com[/url] ]--
The file is not identical with my iTunes 8 encoded file, but the bitrate behavior is similar.

Also this is a surprising result because I have believed that the older iTunes versions always created very restricted VBR files.

MP3 Listening Test at 128 kbps

Reply #293 –
WinXP SP2 clean install, Fatboy 5-sec:
Itunes 6.0.4.2 (QT 7.1): 207 kbps
Itunes 7.7.0.43 (QT 7.50.61.0): 207 kbps

Curiouser and curiouser...
 

MP3 Listening Test at 128 kbps

Reply #294 –
Quote from: lvqcl on
WinXP SP2 clean install, Fatboy 5-sec:
Itunes 6.0.4.2 (QT 7.1): 207 kbps
Itunes 7.7.0.43 (QT 7.50.61.0): 207 kbps

I got about the same bitrate when I encoded the short sample with iTunes 8. EncSpot displayed 208 kbps.

EDIT

What OS and iTunes version did you use when you got 125 kbps?

MP3 Listening Test at 128 kbps

Reply #295 –
Quote from: Alex B on
EncSpot displayed 208 kbps.

Yes. But iTunes itself and foobar2000 report 207kbps.

Quote from: Alex B on
What OS and iTunes version did you use when you got 125 kbps?

WinXP SP3 with a lot of other stuff,  Itunes 7.7.0.43.

BTW: WinXP SP2 clean install, then upgrade to SP3, then install Itunes 7.7.0.43 => 207 kbps. I installed also WMP11 and Aug'2008 DirectX but it didn't change the bitrate.

MP3 Listening Test at 128 kbps

Reply #297 –
What do you think about this:



I used the seven different quality settings (iTunes 8 / XP). The screenshot is from EncSpot.


My previous experience about a year ago was different:

Quote from: Alex B on
... Since you mentioned the iTunes' quality settings we could start with iTunes. I tested some additional iTunes options:



Surprisingly the quality options have almost no effect to the encoding speeds. The very small encoding time differences may be caused by other things as well (I did only one pass). I wonder if these settings do anything, even though there was a very small bitrate increase.

The Smart Encoding Adjustments and Filter Frequencies Below 10 Hz options seem to slightly affect the speed so perhaps they actually do something.

MP3 Listening Test at 128 kbps

Reply #298 –
I'd guess that for some reason iTunes does not always use the set options correctly.

It's unfortunate that no one said anything when I posted my iTunes 7.4.0.28 results a year ago. Though probably not many of us actively use iTunes for MP3 encoding or have experimented with its MP3 settings.

If the Apple developers would have followed what happened here they could have reacted.

MP3 Listening Test at 128 kbps

Reply #299 –
I GET IT!

Dualcore processor => 125 kbps.
Dualcore processor with 1 core disabled => 207 kbps.

I just added "/numproc=1" switch to boot.ini and rebooted. (Setting affinity through Task manager won't help).