[FFmpeg-devel] [PATCH] MLP/TrueHD decoder

[Aurelien Jacobs]

On Sat, 3 Nov 2007 00:49:21 +0100
Michael Niedermayer <michaelni at gmx.at> wrote:

> > +/** Write the audio data into the output buffer.
> > + */
> > +
> > +static int output_data(MLPDecodeContext *m, unsigned int substr)
> > +{
> > +    unsigned int i, ch;
> > +    int32_t sample;
> > +    int16_t *sample_buf16 = (int16_t*)(m->out_buf + m->bytes_output);
> > +
> > +#ifdef CONFIG_AUDIO_NONSHORT
> > +    int32_t *sample_buf32 = (int32_t*)(m->out_buf + m->bytes_output);
> > +
> > +    if (m->avctx->sample_fmt == SAMPLE_FMT_S32) {
> > +        for (i = 0; i < m->blockpos[substr]; i++) {
> > +            for (ch = 0; ch <= m->max_channel[substr]; ch++) {
> > +                sample = m->sample_buffer[i][ch] << m->output_shift[substr][ch];
> > +                m->lossless_check_data[substr] ^= (sample & 0xffffff) << ch;
> > +                *sample_buf32++ = sample << 8;
> > +                m->bytes_output += 4;
> > +            }
> > +        }
> > +    } else
> > +#endif
> > +    {
> > +        for (i = 0; i < m->blockpos[substr]; i++) {
> > +            for (ch = 0; ch <= m->max_channel[substr]; ch++) {
> > +                sample = m->sample_buffer[i][ch] << m->output_shift[substr][ch];
> > +                m->lossless_check_data[substr] ^= (sample & 0xffffff) << ch;
> > +                *sample_buf16++ = (sample) >> 8;
> > +                m->bytes_output += 2;
> > +            }
> > +        }
> > +    }
> > +
> > +    return 0;
> > +}
> 
> 
> static inline void output_data_internal(MLPDecodeContext *m, unsigned int substr, int is32)
> {
>     unsigned int i, ch;
>     for (i = 0; i < m->blockpos[substr]; i++) {
>         for (ch = 0; ch <= m->max_channel[substr]; ch++) {
>             int sample = m->sample_buffer[i][ch] << m->output_shift[substr][ch];
>             m->lossless_check_data[substr] ^= (sample & 0xffffff) << ch;
>             if(is32) *((int32_t*)m->out_ptr)++ = sample << 8;
>             else     *((int16_t*)m->out_ptr)++ = sample >> 8;
>         }
>     }
> }
> 
> static void output_data_internal(MLPDecodeContext *m, unsigned int substr)
> {
>     if(m->avctx->sample_fmt == SAMPLE_FMT_S32) output_data_internal(m, substr, 1);
>     else                                       output_data_internal(m, substr, 0);
> }

I'm astonished you didn't proposed directly this simpler form:

static void output_data(MLPDecodeContext *m, unsigned int substr)
{
    output_data_internal(m, substr, m->avctx->sample_fmt == SAMPLE_FMT_S32);
}

Aurel