[FFmpeg-devel] [PATCH] QCELP decoder

[Michael Niedermayer]

On Wed, Nov 12, 2008 at 09:05:02AM -0800, Kenan Gillet wrote:
> 
> On Nov 11, 2008, at 10:00 AM, Michael Niedermayer wrote:
> 
> > On Sun, Nov 09, 2008 at 09:49:20PM -0800, Kenan Gillet wrote:
[...]
> >> +        const float *predictors = (q->prev_framerate !=  
> >> RATE_OCTAVE ||
> >> +                                   q->prev_framerate != I_F_Q ? q- 
> >> >prev_lspf
> >> +                                                              : q- 
> >> >predictor_lspf);
> >
> > hmmmmmmm
> > hmm
> >
> > Which value is not unequal to either RATE_OCTAVE or I_F_Q ?
> 
> q->prev_framerate : framerate of the previous frame
> q->framerate: framerate of the current frame
> :)

there is no q->framerate in there :)


> 
> 
> The predictor changes based on the rate of the previous frame.
> 
> 
> >
> >
> > Are you testing the code in each patch iteration?
> 
> I do check the output to wav of all the test files I have for every  
> commit in my svn.

great, now i feel better, this is a good strategy

[...]
> >> +        break;
> >> +    case RATE_OCTAVE:
> >> +        cbseed = q->first16bits;
> >> +        for (i = 0; i < 8; i++) {
> >> +            tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0);
> >> +            for (j = 0; j < 20; j++) {
> >> +                cbseed = 521 * cbseed + 259;
> >> +                *cdn_vector++ = tmp_gain * (int16_t)cbseed;
> >> +            }
> >> +        }
> >> +        break;
> >> +    case I_F_Q:
> >> +        cbseed = -44; // random codebook index
> >> +        for (i = 0; i < 4; i++) {
> >> +            tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO;
> >> +            for (j = 0; j < 40; j++)
> >> +                *cdn_vector++ = tmp_gain *  
> >> qcelp_rate_full_codebook[cbseed++ & 127];
> >> +        }
> >> +        break;
> >> +    }
> >> +}
> >> +
> >
> >> +/**
> >> + * Apply generic gain control.
> >> + *
> >> + * @param v_out output vector
> >> + * @param v_in gain-controlled vector
> >> + * @param v_ref vector to control gain of
> >> + *
> >> + * TIA/EIA/IS-733 2.4.8.3-2/3/4/5, 2.4.8.6
> >> + */
> >> +static void apply_gain_ctrl(float *v_out,
> >> +                            const float *v_ref,
> >> +                            const float *v_in) {
> >> +    int   i, j, len;
> >> +    float scalefactor;
> >> +
> >> +    for (i = 0, j = 0; i < 4; i++) {
> >> +        scalefactor = ff_dot_productf(v_in + j, v_in + j, 40);
> >
> >> +        if (scalefactor) {
> >> +            scalefactor = sqrt(ff_dot_productf(v_ref + j, v_ref +  
> >> j, 40) / scalefactor);
> >> +            for (len = j + 40; j < len; j++)
> >> +                v_out[j] = scalefactor * v_in[j];
> >> +        } else {
> >> +            memset(v_out + j, 0,  40 * sizeof(float));
> >> +            j += 40;
> >> +        }
> >
> > assuming this is correct
> 
> it is undefined in the specs and the reference code is setting  
> scalefactor
>   only if both dot product are not zero but sill assign
> v_out[j] = v_in[j] * scalefactor
>   with the unassigned scalefactor :(

interresting, i guess then a  if() av_log_missing_feature() would be
a good idea, so we will get a sample that triggers this



[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you really think that XML is the answer, then you definitly missunderstood
the question -- Attila Kinali
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