-Brading Software Message Board
+--Forum: Mp3/Tag Studio Support and Bug Reports
+---Topic: MP3 files reporting zero for bitrate started by Zardoz
Posted by: Zardoz on June 21 2006,04:39
I have a reasonably large collection of MP3's and some of them report that they have a bitrate of 0. I can see this in more than one program. I use MusicMatch V10 and an Explorer add-on called MP3Ext (http://www.mutschler.de/mp3ext). Both of these report bitrates, track time, frame count and file size of 0, yet Explorer shows the file DOES have a size and a track time. These files do play in MMJB and WinAmp without a problem. When I tried to use MP3TS to repair any of these files, I get the following error "Error opening or extracting info from file: (filename)". All of the repair options acted the same way. These files have full ID3 tags, with all of the standard information like track name, artist, track number and even cover art in them, just like the ones that do not have the problem. I can modify this tag info with either of the before mentioned tools without any problems. I am perplexed as to how I can fix this problem. Any suggestions? None of my files that have this problem are small enough to attach here, and then there's that nasty copyright issue anyway. ;-)
Z
Posted by: Magnus Brading on June 21 2006,12:42
If you send me one of these files (the smallest one) by email, I can take a look at it if you like.
Posted by: Zardoz on June 22 2006,21:22
A sample file should be on the way. Thanks.
Z
Posted by: Magnus Brading on June 25 2006,17:57
The file you sent me was not of mp3 format, it was just a file full of null data (with some strange non-mp3 headers in it), having an ID3v1 and an ID3v2 tag attached to it.
This file cannot possibly be played ok with any kind of player (it does not contain any sound data), unless the player in question really reads the data from somewhere else.
Posted by: Zardoz on June 26 2006,00:28
Ok, I've sent another one, zipped this time for safety.
Z
Posted by: Zardoz on July 05 2006,06:58
Did you get the 2nd file I sent? Have you had a chance to look at it yet?
Thanks in advance.
Z
Posted by: Magnus Brading on July 08 2006,10:24
Yes, sorry for the late reply. This file is corrupted in the beginning of the file, but it seems to contain sound data further in. The real sound data begins at offset 48028 (decimal), and if you were to cut off everything before that, it would work fine.
Posted by: Zardoz on July 13 2006,23:34
What tool would you recommend for doing that trimming work, MP3TS or debug? Also, could you point me in the direction to learn how to recognize where these files are bad so that I can deal with the other files with this issue in my library?
Thanks again.
Z
Posted by: Magnus Brading on July 14 2006,11:31
The file is too corrupted to be automatically repaired with Mp3/Tag Studio, so I can only recommend manual cutting of the first 48027 bytes in a hex-editor right now.
Learning to recognize these problems requires deeper knowledge of the mp3 and ID3v2 formats, including studying many mp3s in a hex-editor. I'm sorry to not be able to give any better tips than that.
Posted by: Zardoz on July 15 2006,22:12
Thanks for looking at the file. Is there any documentation of the tag structure of MP3 files where I can study them and learn to recognize the location of the issue? I also use a tool called GoldWave (an excellent tool, by the way), but when I load one of these files it presents me with a bewildering array of possible formats that the file(s) could be in. I have tried a number of those formats, but I'm swinging in the dark. I'm assuming that There are some common standards that MP3 files use, is that right? I get options for File Type (raw or dialogic), Hertz rate (5500 to 192000), and Attributes which consist of PCM signed and unsigned, Micro-law, A-law, ISDN A-law, ASCII floating and integer and IEEE floating signed. Many of these formats have subformats like the number of bits, stereo or mono and little or big endian. I assume that you understand these options and I am not asking you to teach me, just point me to a reference where I can learn this.
Thanks again!
Z
Posted by: Magnus Brading on July 16 2006,00:35
I'm not sure if all those options apply to mp3 files, I don't recognize them all. Anyway, I mostly base my analysis on a more lower level familiarity with mp3 and tag data, viewing it directly in a hex editor. So the only tips I can give is to view lots of mp3s in a hex editor, and get to know the structure of ID3 tags and mp3 sound data frames, then they become relatively easy to recognize in the pure data dump after a while.
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