[Ffmpeg-devel] [PATCH] MS-GSM support: draft for review

[Benjamin Larsson]

Michael Niedermayer wrote:

>Hi
>
>On Tue, Nov 07, 2006 at 02:19:33PM +0100, Benjamin Larsson wrote:
>  
>
>>Hi.
>>
>>Michael Niedermayer skrev:
>>    
>>
>>>Hi
>>>
>>>      
>>>
>>[...]
>>
>>
>>    
>>
>>> your implementation does not allow -acodec copy between msgsm<->gsm
>>>      
>>>
>>There are other diffrences that won't allow this, just not the double 
>>packing of frames. For this to work the stream would need to pass a 
>>bitstream filter also. 
>>    
>>
>
>could you elaborate on the other things needed? i thought ms just
>packed 2frames together?
>  
>

>From http://kbs.cs.tu-berlin.de/~jutta/toast.html

"Microsoft's GSM 06.10 CODEC is not compatible with toast's frame format
- they use 65-byte-frames (2 x 32 1/2) rather than rounding to 33, and
they number the bits in their bytes from the other end. (Well done, guys.)"

Doing a bitstream filter for that would mean writing a complete
bitstream parser for the format.

MvH
Benjamin Larsson

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