Function mpc7_decode_frame

libavcodec/mpc7.c:178–298

}

static int mpc7_decode_frame(AVCodecContext *avctx, AVFrame *frame,
                             int *got_frame_ptr, AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size;
    MPCContext *c = avctx->priv_data;
    GetBitContext gb;
    int i, ch;
    int mb = -1;
    Band *bands = c->bands;
    int off, ret, last_frame, skip;
    int bits_used, bits_avail;

    memset(bands, 0, sizeof(*bands) * (c->maxbands + 1));

    buf_size = avpkt->size & ~3;
    if (buf_size <= 0) {
        av_log(avctx, AV_LOG_ERROR, "packet size is too small (%i bytes)\n",
               avpkt->size);
        return AVERROR_INVALIDDATA;
    }
    if (buf_size != avpkt->size) {
        av_log(avctx, AV_LOG_WARNING, "packet size is not a multiple of 4. "
               "extra bytes at the end will be skipped.\n");
    }

    skip       = buf[0];
    last_frame = buf[1];
    buf       += 4;
    buf_size  -= 4;

    /* get output buffer */
    frame->nb_samples = MPC_FRAME_SIZE;
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
        return ret;

    av_fast_padded_malloc(&c->bits, &c->buf_size, buf_size);
    if (!c->bits)
        return AVERROR(ENOMEM);
    c->bdsp.bswap_buf((uint32_t *) c->bits, (const uint32_t *) buf,
                      buf_size >> 2);
    if ((ret = init_get_bits8(&gb, c->bits, buf_size)) < 0)
        return ret;
    skip_bits_long(&gb, skip);

    /* read subband indexes */
    for(i = 0; i <= c->maxbands; i++){
        for(ch = 0; ch < 2; ch++){
            int t = i ? get_vlc2(&gb, hdr_vlc, MPC7_HDR_BITS, 1) : 4;
            if(t == 4) bands[i].res[ch] = get_bits(&gb, 4);
            else bands[i].res[ch] = bands[i-1].res[ch] + t;
            if (bands[i].res[ch] < -1 || bands[i].res[ch] > 17) {
                av_log(avctx, AV_LOG_ERROR, "subband index invalid\n");
                return AVERROR_INVALIDDATA;
            }
        }

        if(bands[i].res[0] || bands[i].res[1]){