[FFmpeg-devel] [PATCH] ALS decoder

Justin Ruggles justin.ruggles
Sat Aug 29 01:55:25 CEST 2009


Thilo Borgmann wrote:

> Michael Niedermayer schrieb:
>> On Wed, Aug 26, 2009 at 08:28:43PM +0200, Thilo Borgmann wrote:
>>> Revision 11 attached.
>> [...]
>>> +    if (get_bits_left(&gb) < (22 << 3))
>>> +        return -1;
>> is that the smallest size a valid frame can have? i would have suspect it
>> to be larger
> I don't know. Is the AudioSpecificConfig embedded in something like a
> frame? I don't think there is a minimum size for AudioSpecificConfig and
> determining this by the smallest possible *SpecificConfig would be
> error-prone and would have to be reconsidered whenever 14496-3 changes.

No, the AudioSpecificConfig is not in the frames, it is in the
extradata.  The smallest possible frame is 8 bits.  1 channel, 1 zero
block.  That's 1 bit for block type, 1 bit for const_block, 1 bit for
js_block, and 5 reserved bits.

-Justin



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