libavcodec/h261dec.c:441: error: Integer Overflow L2
  ([0, +oo] - 2):unsigned32 by call to `h261_decode_block`.

libavcodec/h261dec.c:393:26: Call
391.     // Read mquant
392.     if (IS_QUANT(h->mtype))
393.         ff_set_qscale(s, bitstream_read(&s->bc, 5));
                              ^
394. 
395.     s->mb_intra = IS_INTRA4x4(h->mtype);

libavcodec/bitstream.h:182:1: Parameter `bc->bits_left`
  180. 
  181. /* Return n bits from the buffer. n has to be in the 0-32 range. */
  182. static inline uint32_t bitstream_read(BitstreamContext *bc, unsigned n)
       ^
  183. {
  184.     if (!n)

libavcodec/h261dec.c:441:17: Call
439.         s->bdsp.clear_blocks(s->block[0]);
440.         for (i = 0; i < 6; i++) {
441.             if (h261_decode_block(h, s->block[i], i, cbp & 32) < 0)
                     ^
442.                 return SLICE_ERROR;
443.             cbp += cbp;

libavcodec/h261dec.c:259:1: Parameter `h->s.bc.bits_left`
  257.  * @return <0 if an error occurred
  258.  */
  259. static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
       ^
  260. {
  261.     MpegEncContext *const s = &h->s;

libavcodec/h261dec.c:293:21: Call
  291.         // 0    1       1s
  292.         // *    *       0*
  293.         int check = bitstream_peek(&s->bc, 2);
                           ^
  294.         i = 0;
  295.         if (check & 0x2) {

libavcodec/bitstream.h:214:1: Parameter `n`
    212. /* Return n bits from the buffer, but do not change the buffer state.
    213.  * n has to be in the 0-32 range. */
    214. static inline unsigned bitstream_peek(BitstreamContext *bc, unsigned n)
         ^
    215. {
    216.     if (n > bc->bits_left)

libavcodec/h261dec.c:296:13: Call
  294.         i = 0;
  295.         if (check & 0x2) {
  296.             bitstream_skip(&s->bc, 2);
                   ^
  297.             block[0] = (check & 0x1) ? -1 : 1;
  298.             i        = 1;

libavcodec/bitstream.h:240:1: Parameter `n`
    238. 
    239. /* Skip n bits in the buffer. */
    240. static inline void bitstream_skip(BitstreamContext *bc, unsigned n)
         ^
    241. {
    242.     if (n < bc->bits_left)

libavcodec/bitstream.h:243:9: Call
    241. {
    242.     if (n < bc->bits_left)
    243.         skip_remaining(bc, n);
                 ^
    244.     else {
    245.         n -= bc->bits_left;

libavcodec/bitstream.h:229:1: <LHS trace>
227. }
228. 
229. static inline void skip_remaining(BitstreamContext *bc, unsigned n)
     ^
230. {
231. #ifdef BITSTREAM_READER_LE

libavcodec/bitstream.h:229:1: Parameter `bc->bits_left`
      227. }
      228. 
      229. static inline void skip_remaining(BitstreamContext *bc, unsigned n)
           ^
      230. {
      231. #ifdef BITSTREAM_READER_LE

libavcodec/bitstream.h:229:1: <RHS trace>
227. }
228. 
229. static inline void skip_remaining(BitstreamContext *bc, unsigned n)
     ^
230. {
231. #ifdef BITSTREAM_READER_LE

libavcodec/bitstream.h:229:1: Parameter `n`
      227. }
      228. 
      229. static inline void skip_remaining(BitstreamContext *bc, unsigned n)
           ^
      230. {
      231. #ifdef BITSTREAM_READER_LE

libavcodec/bitstream.h:236:5: Binary operation: ([0, +oo] - 2):unsigned32 by call to `h261_decode_block` 
      234.     bc->bits <<= n;
      235. #endif
      236.     bc->bits_left -= n;
               ^
      237. }
      238. 
