IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
MP3 frames, Bitrate combinations
Sebastian Mares
post May 24 2003, 13:24
Post #1





Group: Members
Posts: 3629
Joined: 14-May 03
From: Bad Herrenalb
Member No.: 6613



Hello,

While looking around for some MP3 documentation I have came across the following sites:
As you can see, the bitrate tables are different. ID3.org says that MPEG 2 Layer 2 varies between 32 and 384, while MP3' Tech says that it varies between 8 and 160. Which of the two tables is correct?

Regards,
Sebastian Mares


--------------------
http://listening-tests.hydrogenaudio.org/sebastian/
Go to the top of the page
+Quote Post
john33
post May 24 2003, 14:42
Post #2


xcLame and OggDropXPd Developer


Group: Developer
Posts: 3736
Joined: 30-September 01
From: Bracknell, UK
Member No.: 111



I should go back and read them again if I were you. They say the same thing. wink.gif You're confusing the Version number with the Layer number.


--------------------
John
----------------------------------------------------------------
My compiles and utilities are at http://www.rarewares.org/
Go to the top of the page
+Quote Post
Sebastian Mares
post May 24 2003, 16:41
Post #3





Group: Members
Posts: 3629
Joined: 14-May 03
From: Bad Herrenalb
Member No.: 6613



Actually, I don't!

MP3' Tech says that the lowest bitrate for MPEG 2 Layer II AND III is 8 kbps, while ID3.org says that ONLY MPEG 2 Layer III starts at bitrate 8 kbps.


--------------------
http://listening-tests.hydrogenaudio.org/sebastian/
Go to the top of the page
+Quote Post
john33
post May 24 2003, 16:56
Post #4


xcLame and OggDropXPd Developer


Group: Developer
Posts: 3736
Joined: 30-September 01
From: Bracknell, UK
Member No.: 111



QUOTE (Sebastian Mares @ May 24 2003 - 03:41 PM)
Actually, I don't!

MP3' Tech says that the lowest bitrate for MPEG 2 Layer II AND III is 8 kbps, while ID3.org says that ONLY MPEG 2 Layer III starts at bitrate 8 kbps.

Hmmm, I think my brain must have been out to lunch!! rolleyes.gif

I would tend to trust Gabriel's (mp3tech) since he is a LAME developer. wink.gif


--------------------
John
----------------------------------------------------------------
My compiles and utilities are at http://www.rarewares.org/
Go to the top of the page
+Quote Post
tangent
post May 24 2003, 19:59
Post #5





Group: Members
Posts: 674
Joined: 29-September 01
Member No.: 63



I shall resist against making some mean, sarcastic remarks about the intelligence of the creators of id3v2.
Go to the top of the page
+Quote Post
Sebastian Mares
post May 24 2003, 20:14
Post #6





Group: Members
Posts: 3629
Joined: 14-May 03
From: Bad Herrenalb
Member No.: 6613



laugh.gif Yes...


--------------------
http://listening-tests.hydrogenaudio.org/sebastian/
Go to the top of the page
+Quote Post
Gabriel
post May 25 2003, 10:46
Post #7


LAME developer


Group: Developer
Posts: 2950
Joined: 1-October 01
From: Nanterre, France
Member No.: 138



My copy of the ISO standard gives the same numbers as me.
Go to the top of the page
+Quote Post
Gabriel
post May 25 2003, 10:54
Post #8


LAME developer


Group: Developer
Posts: 2950
Joined: 1-October 01
From: Nanterre, France
Member No.: 138



I checked id3.org, and they are listing the mpeg2 bitrates for layer I and II to be identical to mpeg1 ones.
This is wrong in case of use of mpeg2 low sampling frequencies.

Anyway, layer II lsf should be quite rare. In the standard, the table listing the allowed stereo modes (as in mpeg1) is missing.

It seems that the ISO comitee though about the following:
*if you want to reduce bitrate, then use layer III and not layer II
*if you want multichannel, use layer II, as it's less complew than layer III

Layer III multichannel seems to be completely defined in the standard, however there is no encoder. Even in the ISO compliance bitstreams, there is only 1 layer III mc test sample, and this one is synthetic (not produced by an encoder)
Go to the top of the page
+Quote Post
Sebastian Mares
post May 25 2003, 11:25
Post #9





Group: Members
Posts: 3629
Joined: 14-May 03
From: Bad Herrenalb
Member No.: 6613



Thanks for the information Gabriel! wink.gif

By the way, would it be possible for you to have a look at this tread and maybe answer some of my questions, please?

Best regards,
Sebastian


--------------------
http://listening-tests.hydrogenaudio.org/sebastian/
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 24th April 2014 - 09:47