On 10 August 2014 11:25, Janne Grunau <janne-li...@jannau.net> wrote:
> On 2014-08-10 04:17:09 +0100, Kieran Kunhya wrote:
>> The Opus decoder in particular uses optimised float_dsp functions that
>> expect 32-byte alignment
>> ---
>> libavcodec/avcodec.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
>> index 93aad35..5cbc175 100644
>> --- a/libavcodec/avcodec.h
>> +++ b/libavcodec/avcodec.h
>> @@ -1880,7 +1880,7 @@ typedef struct AVCodecContext {
>> * avcodec_default_get_buffer() instead of providing buffers allocated
>> by
>> * some other means.
>> *
>> - * AVFrame.data[] should be 32- or 16-byte-aligned unless the CPU
>> doesn't
>> + * AVFrame.data[] should be 32-byte-aligned unless the CPU doesn't
>
> NAK. While this is technical true it is not an improvement. Just making
> it a little less ambiguous by removing a correct value (16-byte
> alignment is fine on ARM) makes this documentation good.
>
> It should read "should be aligned to the targets CPU SIMD maximal
> required alignment."
>
> I'll add some some examples and will sent a patch later today.
If vector_fmac requires 32-byte alignment (irrespective of cpu) then
the API/ABI should reflect that.
If not then vector_fmac should be changed.
Kieran
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