[ID3 Dev] How do you know ID3 v1 without ID3v2

[Jim]

I might be confused but I think what he is asking is if a MP3 file that
does not have an ID3v2 tag could somehow start with the characters "ID3".

Or another way to say it is could there be "ID3" at the start of a MP3
file but it is not a ID3v2 tag?

I don't think this would happen but I also think that garbage data can
sometimes appear at the beginning of an MP3 file.  So I don't think it
is impossible.  I think that's why some players search for a certain
"sync" pattern to identify the start of the real data.  Can someone
confirm this?  (Or am I completely off on this?)

Jim




Jud White wrote:
> No, frame headers would never start with ID3.
> 
> hongyang wrote:
>> Thanks,
>>
>> I think maybe you misunderstand me, I mean whether the situation could
>> happen, the MP3 music media data(not the Tag frame data) start with
>> "ID3", but this "ID3" is not the ID3v2 Tag's identifier.
>>
>> In fact the MP3 file without ID3v2 Tags, only ID3v1 exist.
>>
>> do you think this situation would like happen.
>>
>> thank u again...
>>
>> Jud White 写道:
>>> An ID3v2 tag can be detected with the following pattern:
>>> $49 44 33 yy yy xx zz zz zz zz
>>> Where yy is less than $FF, xx is the 'flags' byte and zz is less than $80.
>>>
>>> http://id3.org/id3v2.3.0#head-697d09c50ed7fa96fb66c6b0a9d93585e2652b0b
>>>
>>>
>>> hongyang wrote:
>>>   
>>>> Hello everyone,
>>>>
>>>> I have a quesetion, if I know the .mp3 file has ID3v1 Tag, and I am not
>>>> sure whether it also has ID3v2 Tag.Now whether the condition would happend
>>>> that the start of media data are "ID3" ,but the "ID3" is not the
>>>> identifier of ID3v2.
>>>>
>>>> My english is very poor,so please forgave me.
>>>>
>>>> Thank you all.
>>>>
>>>> hongyang
>>>>
>>>>
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>>>>     
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> 
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