Function mpc8_decode_init

libavcodec/mpc8.c:141–185

}

static av_cold int mpc8_decode_init(AVCodecContext * avctx)
{
    static AVOnce init_static_once = AV_ONCE_INIT;
    MPCContext *c = avctx->priv_data;
    GetBitContext gb;
    int channels;

    if(avctx->extradata_size < 2){
        av_log(avctx, AV_LOG_ERROR, "Too small extradata size (%i)!\n", avctx->extradata_size);
        return -1;
    }
    memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
    av_lfg_init(&c->rnd, 0xDEADBEEF);
    ff_mpadsp_init(&c->mpadsp);

    init_get_bits(&gb, avctx->extradata, 16);

    uint8_t sample_rate_idx = get_bits(&gb, 3);
    static const int sample_rates[] = { 44100, 48000, 37800, 32000 };
    if (sample_rate_idx >= FF_ARRAY_ELEMS(sample_rates)) {
        av_log(avctx, AV_LOG_ERROR, "invalid sample rate index (%u)\n", sample_rate_idx);
        return AVERROR_INVALIDDATA;
    }
    avctx->sample_rate = sample_rates[sample_rate_idx];
    c->maxbands = get_bits(&gb, 5) + 1;
    if (c->maxbands >= BANDS) {
        av_log(avctx,AV_LOG_ERROR, "maxbands %d too high\n", c->maxbands);
        return AVERROR_INVALIDDATA;
    }
    channels = get_bits(&gb, 4) + 1;
    if (channels > 2) {
        avpriv_request_sample(avctx, "Multichannel MPC SV8");
        return AVERROR_PATCHWELCOME;
    }
    c->MSS = get_bits1(&gb);
    c->frames = 1 << (get_bits(&gb, 3) * 2);

    avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
    av_channel_layout_uninit(&avctx->ch_layout);
    av_channel_layout_default(&avctx->ch_layout, channels);

    ff_thread_once(&init_static_once, mpc8_init_static);

    return 0;
}

static int mpc8_decode_frame(AVCodecContext *avctx, AVFrame *frame,
                             int *got_frame_ptr, AVPacket *avpkt)