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

Young Han Lee cpumaker
Mon Feb 14 09:15:17 CET 2011


On Mon, Feb 14, 2011 at 4:55 PM, Rob <robert.swain at gmail.com> wrote:

> 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
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at mplayerhq.hu
> https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel
>

I misunderstood it.
now I fix it.

Thanks,
Young Han
-------------- next part --------------
A non-text attachment was scrubbed...
Name: AAC_DEC_LTP-011.patch
Type: text/x-patch
Size: 14282 bytes
Desc: not available
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20110214/df1a6f48/attachment.bin>



More information about the ffmpeg-devel mailing list