Vorbis dev - Jul 2001 - oggenc broken for some types of WAV files

Hello,

I have found that there are some WAV files which have a "fmt" chunk
size greater
then 16 bytes (length indicator greater then 16).  The patch is attached.

What is the normal method for submiting patches?

Regards,

Chris Wolf


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At 01:23 AM 7/28/01 -0700, you wrote:
>Hello,
>
>I have found that there are some WAV files which have a "fmt"
chunk size greater
>then 16 bytes (length indicator greater then 16).  The patch is attached.
>
>What is the normal method for submiting patches?
>
The normal method is to send them to the list, as you've done.

Your patch is incorrect (will cause crashes if used). There's already a
special case for allowing the "fmt " chunk to be of length 18 - this
is
incorrect according to every wav spec I've been able to find, but is 
common. However, allowing arbitrarily long fmt chunks is definately not
a good idea, so I won't be changing this behaviour unless you can show
me an official wav spec that says this is allowed. 

The application that is creating these files is presumably buggy.

Michael

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>At 01:23 AM 7/28/01 -0700, you wrote:
>
>Your patch is incorrect (will cause crashes if used). There's already a
>special case for allowing the "fmt " chunk to be of length 18 -
this is
>incorrect according to every wav spec I've been able to find, but is 
>common.
To give a longer explaination....

The spec's for WAV's sitting n my hard drive says the 4 bytes at
offset 16 of the WAV file the fmt subchunk holds the length 
of the fmt subchunk.

Its supposed to be 16 for files that are pure PCM,but the spec allows
for extra bits of data at offset 36 before the data subchunck no matter
what the format.

The true test for the data being PCM is the two bytes at offset 20
being equal to 1.

Dave

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