Function ac3_decode_init

libavcodec/ac3dec.c:97–147

* AVCodec initialization */

 * AVCodec initialization
 */
static av_cold int ac3_decode_init(AVCodecContext *avctx)
{
    AC3DecodeContext *s = avctx->priv_data;
    const float scale = 1.0f;
    int i, ret;

    s->avctx = avctx;

    if ((ret = av_tx_init(&s->tx_128, &s->tx_fn_128, IMDCT_TYPE, 1, 128, &scale, 0)))
        return ret;

    if ((ret = av_tx_init(&s->tx_256, &s->tx_fn_256, IMDCT_TYPE, 1, 256, &scale, 0)))
        return ret;

    AC3_RENAME(ff_kbd_window_init)(s->window, 5.0, 256);
    ff_bswapdsp_init(&s->bdsp);

#if (USE_FIXED)
    s->fdsp = avpriv_alloc_fixed_dsp(avctx->flags & AV_CODEC_FLAG_BITEXACT);
#else
    ff_fmt_convert_init(&s->fmt_conv);
    s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
#endif
    if (!s->fdsp)
        return AVERROR(ENOMEM);

    ff_ac3dsp_init(&s->ac3dsp);
    av_lfg_init(&s->dith_state, 0);

    if (USE_FIXED)
        avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
    else
        avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;

    ac3_downmix(avctx);
    s->downmixed = 1;

    for (i = 0; i < AC3_MAX_CHANNELS; i++) {
        s->xcfptr[i] = s->transform_coeffs[i];
        s->dlyptr[i] = s->delay[i];
    }

#if USE_FIXED
    ff_ac3_init_static();
#else
    static AVOnce init_static_once = AV_ONCE_INIT;
    ff_thread_once(&init_static_once, ac3_float_tables_init);
#endif

    return 0;
}

static av_cold void ac3_decode_flush(AVCodecContext *avctx)
{