[FFmpeg-devel] [PATCH] AAC decoder

Michael Niedermayer michaelni
Tue May 20 23:31:12 CEST 2008


On Tue, May 20, 2008 at 02:23:15PM +0100, Robert Swain wrote:
> 2008/4/2 Michael Niedermayer <michaelni at gmx.at>:
> > On Tue, Apr 01, 2008 at 04:56:48PM +0200, Andreas ?man wrote:
> >> Andreas ?man wrote:
> > [...]
> >> +/**
> >> + * Set up program_config_struct, but based on a default channel configuration
> >> + * as specified in Table 1.17
> >> + */
> >> +static int program_config_element_default(AACContext *ac, int channels)
> >> +{
> >> +    program_config_struct pcs;
> >> +
> >> +    memset(&pcs, 0, sizeof(program_config_struct));
> >> +
> >> +    /* Premixed downmix outputs are not available */
> >> +    pcs.mono_mixdown   = -1;
> >> +    pcs.stereo_mixdown = -1;
> >> +
> >> +    switch(channels) {
> >> +    case 1: /* Mono */
> >> +        pcs.sce_type[0] = AAC_CHANNEL_FRONT;
> >> +        break;
> >> +
> >> +    case 2: /* Stereo */
> >> +        pcs.cpe_type[0] = AAC_CHANNEL_FRONT;
> >> +        break;
> >> +
> >> +    case 3: /* Front Center + L + R  */
> >> +        pcs.sce_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[0] = AAC_CHANNEL_FRONT;
> >> +        break;
> >> +
> >> +    case 4: /* Front Center + L + R + Back Center */
> >> +        pcs.sce_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.sce_type[1] = AAC_CHANNEL_BACK;
> >> +        break;
> >> +
> >> +    case 5: /* Front Center + L + R + Back Stereo */
> >> +        pcs.sce_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[1] = AAC_CHANNEL_BACK;
> >> +        break;
> >> +
> >> +    case 6: /* Front Center + L + R + Back Stereo + LFE */
> >> +        pcs.sce_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[1] = AAC_CHANNEL_BACK;
> >> +        pcs.lfe_type[0] = AAC_CHANNEL_LFE;
> >> +        break;
> >> +
> >> +    case 7: /* Front Center + L + R + Outer Front Left + Outer Front Right + Back Stereo + LFE */
> >> +        pcs.sce_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[0] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[1] = AAC_CHANNEL_FRONT;
> >> +        pcs.cpe_type[2] = AAC_CHANNEL_BACK;
> >> +        pcs.lfe_type[0] = AAC_CHANNEL_LFE;
> >> +        break;
> >> +
> >> +    default:
> >> +        av_log(ac->avccontext, AV_LOG_ERROR, "Invalid default channel configuration (%d channels)\n",
> >> +               channels);
> >> +        return -1;
> >> +    }
> >
> > Above is full of code duplication and can be done simpler.
> >
> > [...]
> 
> How about the attached patch?

looks better

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

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
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