avcodec/takdec: Fix integer overflow in decode_subframe()

Fixes: runtime error: signed integer overflow: -536870912 - 1972191120 cannot be represented in type 'int'
Fixes: 2711/clusterfuzz-testcase-minimized-4975142398590976

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg


Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/takdec.c

@@ -491,7 +491,7 @@ static int decode_subframe(TAKDecContext *s, int32_t *decoded,
                      s->residues[i + j + 1] * s->filter[j + 1] +
                      s->residues[i + j    ] * s->filter[j    ];
             }
-            v = (av_clip_intp2(v >> filter_quant, 13) * (1 << dshift)) - *decoded;
+            v = (av_clip_intp2(v >> filter_quant, 13) * (1 << dshift)) - (unsigned)*decoded;
             *decoded++ = v;
             s->residues[filter_order + i] = v >> dshift;
         }