avcodec/mpeg4videoenc: Use 64 bit for times in mpeg4_encode_gop_header()

Fixes truncation
Fixes Assertion n <= 31 && value < (1U << n) failed at libavcodec/put_bits.h:169
Fixes: ffmpeg_crash_2.avi

Found-by: Thuan Pham <thuanpv@comp.nus.edu.sg>, Marcel Böhme, Andrew Santosa and Alexandru RazvanCaciulescu with AFLSmart

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
static inline int get_b_cbp(MpegEncContext *s, int16_t block[6][64],
                            int motion_x, int motion_y, int mb_type)
{
    int cbp = 0, i;

    if (s->mpv_flags & FF_MPV_FLAG_CBP_RD) {
        int score        = 0;
        const int lambda = s->lambda2 >> (FF_LAMBDA_SHIFT - 6);

        for (i = 0; i < 6; i++) {
            if (s->coded_score[i] < 0) {
                score += s->coded_score[i];
                cbp   |= 1 << (5 - i);
            }
        }

        if (cbp) {
            int zero_score = -6;
            if ((motion_x | motion_y | s->dquant | mb_type) == 0)
                zero_score -= 4;  // 2 * MV + mb_type + cbp bit

            zero_score *= lambda;
            if (zero_score <= score)
                cbp = 0;
        }

        for (i = 0; i < 6; i++) {
            if (s->block_last_index[i] >= 0 && ((cbp >> (5 - i)) & 1) == 0) {
                s->block_last_index[i] = -1;
                s->bdsp.clear_block(s->block[i]);
            }
        }
    } else {
        for (i = 0; i < 6; i++) {
            if (s->block_last_index[i] >= 0)
                cbp |= 1 << (5 - i);
        }
    }
    return cbp;
}

static inline int get_b_cbp(MpegEncContext *s, int16_t block[6][64],
                            int motion_x, int motion_y, int mb_type)
{
    int cbp = 0, i;

    if (s->mpv_flags & FF_MPV_FLAG_CBP_RD) {
        int score        = 0;
        const int lambda = s->lambda2 >> (FF_LAMBDA_SHIFT - 6);

        for (i = 0; i < 6; i++) {
            if (s->coded_score[i] < 0) {
                score += s->coded_score[i];
                cbp   |= 1 << (5 - i);
            }
        }

        if (cbp) {
            int zero_score = -6;
            if ((motion_x | motion_y | s->dquant | mb_type) == 0)
                zero_score -= 4;  // 2 * MV + mb_type + cbp bit

            zero_score *= lambda;
            if (zero_score <= score)
                cbp = 0;
        }

        for (i = 0; i < 6; i++) {
            if (s->block_last_index[i] >= 0 && ((cbp >> (5 - i)) & 1) == 0) {
                s->block_last_index[i] = -1;
                s->bdsp.clear_block(s->block[i]);
            }
        }
    } else {
        for (i = 0; i < 6; i++) {
            if (s->block_last_index[i] >= 0)
                cbp |= 1 << (5 - i);
        }
    }
    return cbp;
}
