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Author Topic: CBR MPEG-1 Layer 2  (Read 3189 times)

Magic_Randy

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CBR MPEG-1 Layer 2
« on: November 21, 2006, 07:11:26 pm »

SwellGuy,

Refer to your question in 12.0.117 thread.

http://yabb.jriver.com/interact/index.php?topic=37198.msg254126#msg254126

I only have 3 files that tagged as CBR MPEG-1 Layer 2.  None of these were ripped using MC.  All of these are MP3 files. 

MC transfers these files to the iPod, but they won't play on the iPod.  They play fine in MC.

2 of them are on an album that has 100 tracks (Top 100 of 1969).  Only 2 are CBR MPEG-1 Layer 2.

1 of them is from an album with 100 tracks (Top 100 of 1979).  This is the only 1 that is CBR MPEG-1 Layer 2.

All tracks on these albums are MP3s.  All of the other tracks are tagged  CBR MPEG-1 Layer 3

Randy

EDIT:  SwellGuy -  Alex helped me out so I think you can ignore this post.  I thought this may have been an MC issue, but it looks like a few MP2s sneaked into my MP3 library.
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Alex B

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Re: CBR MPEG-1 Layer 2
« Reply #1 on: November 21, 2006, 08:06:25 pm »

I only have 3 files that tagged as CBR MPEG-1 Layer 2.  None of these were ripped using MC.  All of these are MP3 files. 

MC transfers these files to the iPod, but they won't play on the iPod.  They play fine in MC.

2 of them are on an album that has 100 tracks (Top 100 of 1969).  Only 2 are CBR MPEG-1 Layer 2.

1 of them is from an album with 100 tracks (Top 100 of 1979).  This is the only 1 that is CBR MPEG-1 Layer 2.

All tracks on these albums are MP3s.  All of the other tracks are tagged  CBR MPEG-1 Layer 3

http://en.wikipedia.org/wiki/MPEG-1_Audio_Layer_II

If a file is in MPEG-1 layer 2 format it is not MP3. Changing the filename extension does not change the format.

Unfortunately MC does not corretly import MP2 files even though MC can decode and tag them without problems if the extension is changed to MP3 before importing. I have recently reported this. If MC would detect MP2 correctly as an internally supported audio format it could then convert MP2 files on the fly when needed.


As a workaround, I recommend ripping the original CDs in a supported format.  ;)
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Magic_Randy

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Re: CBR MPEG-1 Layer 2
« Reply #2 on: November 21, 2006, 08:16:11 pm »

http://en.wikipedia.org/wiki/MPEG-1_Audio_Layer_II

If a file is in MPEG-1 layer 2 format it is not MP3. Changing the filename extension does not change the format.

Unfortunately MC does not corretly import MP2 files even though MC can decode and tag them without problems after the extension is changed to MP3. I have recently reported this. If MC would detect MP2 correctly as an internally supported audio format it could then convert MP2 files on the fly when needed.


As a workaround, I recommend ripping the original CDs in a supported format.  ;)

Alex,

Do you think the tag could be incorrect?  It's strange that out of 200 tracks, 197 would be MP3 files and 3 would be MP2 files.  All 200 are named as MP3 files, but 3 have a compression tag of MPEG-1 Layer 2 and 197 have a tag of of MPEG-1 Layer 3.

Unfortunately, my son borrowed the albums we are discussing, so I cannot rip them again.  I can figure out something, it's just kind of strange.

Randy
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Alex B

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Re: CBR MPEG-1 Layer 2
« Reply #3 on: November 21, 2006, 08:23:53 pm »

The displayed info in AW > Tag > Format is probably accurate. It shows information directly from the file.

The "Compression" library field can be wrong or empty without causing any changes to the program behavior. It is only informational.


Here is my post from the 12.0.113 thread:


MP2 audio files

MC's internal MPEG 1 Layer 2/3 decoder can handle these perfectly fine including tagging, but the ".mp2" extension (MPEG 1 Layer 2 format) is not correctly associated with MC's decoder.

If I manually change the ".mp2" extension to ".mp3" before importing MC handles the file correctly.

BillT has encountered the same problem:
http://yabb.jriver.com/interact/index.php?topic=31610.msg217257#msg217257

Format info from a test file (filename: MP2 Test File.mp3)

Code: [Select]
MPEG-1 Layer 2
384 Kbit CBR
44.1 Khz Stereo

Copyrighted: No
Original: No
Protected by CRC: No
Gapless: No

ID3v1 Tag: (128 bytes)
   Name: MP2 Test File
   Artist:
   Album:
   Year:
   Comment:
   Track #: 0
   Genre: undefined (255)

ID3v2.3 Tag: (533 bytes)
  TIT2 (Title): MP2 Test File
  TBPM (BPM (beats per min..): 100
  COMM (Comments):
  COMM (Tool Name): Media Center
  COMM (Tool Version): 12.0.113
  COMM (Peak Level): 0,96481
  COMM (Replay Gain): -2,7494800000000001
  COMM (Intensity): 1


Actually, all MPEG extensions should be checked. I have already done some of the needed ground research for you:

Quote from: Alex B on Sat 28.01.2006, 01:34
Quote
MC has currently these MPEG file associations (besides the MP3 and MP4 variants):
mpa, mpga, mp2, mpeg, mpg, m1v, mpv, mpe, m2v

I have Steinberg's Wavelab 5 (a pro audio editor). It has an MPEG-1 Layer 2 encoder.
The offered file extension options are: mp2, mpa, mpg, mus

I remember now that I have previously changed the Media Type of my MP2 audio files because MC imported them as video. Afterall, I think the best system would be this:


mpg, mpeg, m1v, m2v, mpe, mpv, m2p, mpv2, mp2v, mpeg2  => Video

mp2, mpa, mpga, mp2a  => Audio  (use the internal MPEG audio decoder)

mp1 => Audio  (I don't have any files in Layer 1 format, so I don't know if these work)


"mus" is used by the well-known Finale notation software for its proprietary format and I have never seen a .mus MPEG audio file so I guess it is not needed.


EDIT: Added m2p, it is used by Canopus for MPEG2 videos.

EDIT2: Added more extensions. The oldest MPEG-1 layer 1 audio format uses mp1. Sometimes the mp2a (MPEG-1 layer 2 audio), mpv2, mp2v and mpeg2 (MPEG-2 video) extensions are used too.
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Magic_Randy

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Re: CBR MPEG-1 Layer 2
« Reply #4 on: November 21, 2006, 08:51:05 pm »

Alex,

Thanks for all the information.  I checked all 200 tracks from those 2 albums.  Only these 3 tracks are an issue.  I'm not sure how I got this mixture, but I'll come up with a way to replace the MP2 files with MP3 files.

Randy
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Magic_Randy

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Re: CBR MPEG-1 Layer 2
« Reply #5 on: November 23, 2006, 12:50:50 pm »

Alex,

Just to close this thread out, I used the MC feature of converting format to convert the MP2 files to MP3s.  It did not care that they were already called MP3 files (even though they were MP2s).

Again, thanks for your help.

Randy
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