[FFmpeg-devel] [PATCH] AAC Decoder - Round 2.

[Robert Swain]

2008/6/20 Michael Niedermayer <michaelni at gmx.at>:
> On Thu, Jun 19, 2008 at 04:22:57PM +0100, Robert Swain wrote:
>> +    for (i = 0; i < 128; i++) {
>> +        sine_short_128[i] *= 8.;
>> +        kbd_short_128[i] *= 8.;
>> +    }
>
> not thread safe, you cannot store wrong values in static tables and then
> correct them.

OK. I'm not really familiar with thread safety as I haven't written
any threaded code myself to date or read about writing threaded code,
but I think I understand.

To clarify, the issue is that the values of the tables are reassigned
with different values meaning that at different times after
initialisation, the table values change. Separate threads using these
tables then have the potential to use incorrect values. So, such
alterations must be done either before assignment to the table within
the initialisation functions or when using the tables in the code. Is
that correct?

As this alteration is specific to the use of eight short windows (I
think) I'm inclined to not hack it into the init functions but rather
multiply by 8.0 at some other appropriate point in the code. Would you
agree?

Rob