[FFmpeg-devel] [PATCH] Implement AAC Long Term Prediction (LTP) decoding module

[Rob]

On 14 February 2011 02:27, Young Han Lee <cpumaker at gmail.com> wrote:
> On Mon, Feb 14, 2011 at 6:46 AM, Alex Converse <alex.converse at gmail.com>wrote:
>
>> On Sun, Feb 13, 2011 at 5:56 AM, Young Han Lee <cpumaker at gmail.com> wrote:
>> >
>> > any comment about this?
>>
>> It looks good, one last thought
>>
>> +static void windowing_and_mdct_ltp(AACContext *ac, float *out,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? float *in, IndividualChannelStream
>> *ics)
>> +{
>> + ? ?const float * lwindow ? ? ?= ics->use_kb_window[0] ?
>> ff_aac_kbd_long_1024 : ff_sine_1024;
>> + ? ?const float * swindow ? ? ?= ics->use_kb_window[0] ?
>> ff_aac_kbd_short_128 : ff_sine_128;
>> + ? ?const float * lwindow_prev = ics->use_kb_window[1] ?
>> ff_aac_kbd_long_1024 : ff_sine_1024;
>> + ? ?const float * swindow_prev = ics->use_kb_window[1] ?
>> ff_aac_kbd_short_128 : ff_sine_128;
>> + ? ?float * buf = ac->buf_mdct;
>>
>> buf is the same as in should lets just drop buf and call it in.
>>
>>
> Is it just use the "ac->buf_mdct" instead of "*buf"
> If yes, I'll change the rest of "*buf".

In apply_ltp(), predTime is ac->buf_mdct. predTime is pass to
windowing_and_mdct_ltp() as the 'in' argument. Within
windowing_and_mdct_ltp() you also made another variable called buf
that points to ac->buf_mdct. As buf == 'in', buf is redundant and it
would be clearer if 'in' were used for both throughout the function.
e.g.

+        ac->dsp.vector_fmul(ac->buf_mdct, in, lwindow_prev, 1024);

could be

+        ac->dsp.vector_fmul(in, in, lwindow_prev, 1024);

as in == ac->buf_mdct and this change makes it clearer tot he reader
that they are the same.

Regards,
Rob