[FFmpeg-devel] [PATCH] allow high audio sample rates in mov/mp4 muxer

Baptiste Coudurier baptiste.coudurier
Sun Jun 13 01:28:51 CEST 2010

On 6/12/10 8:26 AM, Justin Ruggles wrote:
> Baptiste Coudurier wrote:
>> On 06/10/2010 01:27 PM, Justin Ruggles wrote:
>>> Alex Converse wrote:
>>>> On Thu, Jun 10, 2010 at 1:54 PM, Justin Ruggles
>>>> <justin.ruggles at gmail.com>   wrote:
>>>>> Hi,
>>>>> This patch allows the use of sample rates>   65535 in mov/mp4 (e.g. 96kHz
>>>>> and 192kHz).  I don't know where to find this info in the MP4 spec, but
>>>>> this is how the MPEG-4 ALS Reference Software does it.
>>>> It might also be a good idea to look at the AAC 88.2/96 kHz test vectors.
>>> Well, it seems that it shouldn't be 0, but should be the actual sample
>>> rate using more than 16 bits.  I guess the reserved value that follows
>>> is no longer reserved.  I'll send a new patch soon.
>> Humm, I don't feel confident about this.
>> Can we ask ISO about this ?
> Ok, so after some more research, it looks like the reference samples and
> the specs are in agreement that the sample rate field is 16.16 fixed
> point and that only the low 16 bits of the sample rate are written.

Can you please quote the specs ? Just for reference.

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