libavcodec/proresenc.c:275: error: Uninitialized Value
  The value read from sign was never initialized.

libavcodec/proresenc.c:275:9: 
273.         delta    = dc - prev_dc;
274.         new_sign = GET_SIGN(delta);
275.         delta    = (delta ^ sign) - sign;
             ^
276.         code     = MAKE_CODE(delta);
277.         encode_vlc_codeword(pb, ff_prores_dc_codebook[codebook], code);

static void encode_dcs(PutBitContext *pb, DCTELEM *blocks,
                       int blocks_per_slice, int scale)
{
    int i;
    int codebook = 3, code, dc, prev_dc, delta, sign, new_sign;
    prev_dc = (blocks[0] - 0x4000) / scale;
    encode_vlc_codeword(pb, FIRST_DC_CB, MAKE_CODE(prev_dc));
    codebook = 3;
    blocks  += 64;
    for (i = 1; i < blocks_per_slice; i++, blocks += 64) {
        dc       = (blocks[0] - 0x4000) / scale;
        delta    = dc - prev_dc;
        new_sign = GET_SIGN(delta);
        delta    = (delta ^ sign) - sign;
        code     = MAKE_CODE(delta);
        encode_vlc_codeword(pb, ff_prores_dc_codebook[codebook], code);
        codebook = (code + (code & 1)) >> 1;
        codebook = FFMIN(codebook, 3);
        sign     = new_sign;
        prev_dc  = dc;
    }
}
['static void encode_dcs(PutBitContext *pb, DCTELEM *blocks,\n                       int blocks_per_slice, int scale)\n{\n    int i;\n    int codebook = 3, code, dc, prev_dc, delta, sign, new_sign;\n    prev_dc = (blocks[0] - 0x4000) / scale;\n    encode_vlc_codeword(pb, FIRST_DC_CB, MAKE_CODE(prev_dc));\n    codebook = 3;\n    blocks  += 64;\n    for (i = 1; i < blocks_per_slice; i++, blocks += 64) {\n        dc       = (blocks[0] - 0x4000) / scale;\n        delta    = dc - prev_dc;\n        new_sign = GET_SIGN(delta);\n        delta    = (delta ^ sign) - sign;\n        code     = MAKE_CODE(delta);\n        encode_vlc_codeword(pb, ff_prores_dc_codebook[codebook], code);\n        codebook = (code + (code & 1)) >> 1;\n        codebook = FFMIN(codebook, 3);\n        sign     = new_sign;\n        prev_dc  = dc;\n    }\n}']