Function tgv_decode_inter

libavcodec/eatgv.c:148–262

* Decode inter-frame * @return 0 on success, -1 on critical buffer underflow */

 * @return 0 on success, -1 on critical buffer underflow
 */
static int tgv_decode_inter(TgvContext *s, AVFrame *frame,
                            const uint8_t *buf, const uint8_t *buf_end)
{
    int num_mvs;
    int num_blocks_raw;
    int num_blocks_packed;
    int vector_bits;
    int i,j,x,y;
    GetBitContext gb;
    int mvbits;
    const uint8_t *blocks_raw;

    if(buf_end - buf < 12)
        return AVERROR_INVALIDDATA;

    num_mvs           = AV_RL16(&buf[0]);
    num_blocks_raw    = AV_RL16(&buf[2]);
    num_blocks_packed = AV_RL16(&buf[4]);
    vector_bits       = AV_RL16(&buf[6]);
    buf += 12;

    if (vector_bits > MIN_CACHE_BITS || !vector_bits) {
        av_log(s->avctx, AV_LOG_ERROR,
               "Invalid value for motion vector bits: %d\n", vector_bits);
        return AVERROR_INVALIDDATA;
    }

    /* allocate codebook buffers as necessary */
    if (num_mvs > s->num_mvs) {
        int err = av_reallocp_array(&s->mv_codebook, num_mvs, sizeof(*s->mv_codebook));
        if (err < 0) {
            s->num_mvs = 0;
            return err;
        }
        s->num_mvs = num_mvs;
    }

    if (num_blocks_packed > s->num_blocks_packed) {
        int err;
        if ((err = av_reallocp(&s->block_codebook, num_blocks_packed * 16)) < 0) {
            s->num_blocks_packed = 0;
            return err;
        }
        s->num_blocks_packed = num_blocks_packed;
    }

    /* read motion vectors */
    mvbits = (num_mvs * 2 * 10 + 31) & ~31;

    if (buf_end - buf < (mvbits>>3) + 16*num_blocks_raw + 8*num_blocks_packed)
        return AVERROR_INVALIDDATA;

    init_get_bits(&gb, buf, mvbits);
    for (i = 0; i < num_mvs; i++) {
        s->mv_codebook[i][0] = get_sbits(&gb, 10);
        s->mv_codebook[i][1] = get_sbits(&gb, 10);
    }
    buf += mvbits >> 3;