[libfuzzer] tweaking mp4 fuzzer: dictionary and max_len.

testing/libfuzzer/fuzzers/dicts/mp4.dict

Index: testing/libfuzzer/fuzzers/dicts/mp4.dict
diff --git a/testing/libfuzzer/fuzzers/dicts/mp4.dict b/testing/libfuzzer/fuzzers/dicts/mp4.dict
new file mode 100644
index 0000000000000000000000000000000000000000..d6c29e63b30d409d30d87d36d5ac7bb3a781a648
--- /dev/null
+++ b/testing/libfuzzer/fuzzers/dicts/mp4.dict
@@ -0,0 +1,80 @@
+FOURCC_NULL="\x00\x00\x00\x00"
+FOURCC_AC3 ="\x61\x63\x2d\x33"
+FOURCC_EAC3="\x65\x63\x2d\x33"
+FOURCC_AVC1="\x61\x76\x63\x31"
+FOURCC_AVC3="\x61\x76\x63\x33"
+FOURCC_AVCC="\x61\x76\x63\x43"
+FOURCC_BLOC="\x62\x6C\x6F\x63"
+FOURCC_CENC="\x63\x65\x6e\x63"
+FOURCC_CO64="\x63\x6f\x36\x34"
+FOURCC_CTTS="\x63\x74\x74\x73"
+FOURCC_DINF="\x64\x69\x6e\x66"
+FOURCC_EDTS="\x65\x64\x74\x73"
+FOURCC_EMSG="\x65\x6d\x73\x67"
+FOURCC_ELST="\x65\x6c\x73\x74"
+FOURCC_ENCA="\x65\x6e\x63\x61"
+FOURCC_ENCV="\x65\x6e\x63\x76"
+FOURCC_ESDS="\x65\x73\x64\x73"
+FOURCC_FREE="\x66\x72\x65\x65"
+FOURCC_FRMA="\x66\x72\x6d\x61"
+FOURCC_FTYP="\x66\x74\x79\x70"
+FOURCC_HDLR="\x68\x64\x6c\x72"
+FOURCC_HINT="\x68\x69\x6e\x74"
+FOURCC_HVC1="\x68\x76\x63\x31"
+FOURCC_HVCC="\x68\x76\x63\x43"
+FOURCC_IODS="\x69\x6f\x64\x73"
+FOURCC_MDAT="\x6d\x64\x61\x74"
+FOURCC_MDHD="\x6d\x64\x68\x64"
+FOURCC_MDIA="\x6d\x64\x69\x61"
+FOURCC_MECO="\x6d\x65\x63\x6f"
+FOURCC_MEHD="\x6d\x65\x68\x64"
+FOURCC_META="\x6d\x65\x74\x61"
+FOURCC_MFHD="\x6d\x66\x68\x64"
+FOURCC_MFRA="\x6d\x66\x72\x61"
+FOURCC_MINF="\x6d\x69\x6e\x66"
+FOURCC_MOOF="\x6d\x6f\x6f\x66"
+FOURCC_MOOV="\x6d\x6f\x6f\x76"
+FOURCC_MP4A="\x6d\x70\x34\x61"
+FOURCC_MP4V="\x6d\x70\x34\x76"
+FOURCC_MVEX="\x6d\x76\x65\x78"
+FOURCC_MVHD="\x6d\x76\x68\x64"
+FOURCC_PASP="\x70\x61\x73\x70"
+FOURCC_PDIN="\x70\x64\x69\x6e"
+FOURCC_PRFT="\x70\x72\x66\x74"
+FOURCC_PSSH="\x70\x73\x73\x68"
+FOURCC_SAIO="\x73\x61\x69\x6f"
+FOURCC_SAIZ="\x73\x61\x69\x7a"
+FOURCC_SBGP="\x73\x62\x67\x70"
+FOURCC_SCHI="\x73\x63\x68\x69"
+FOURCC_SCHM="\x73\x63\x68\x6d"
+FOURCC_SDTP="\x73\x64\x74\x70"
+FOURCC_SEIG="\x73\x65\x69\x67"
+FOURCC_SENC="\x73\x65\x6e\x63"
+FOURCC_SGPD="\x73\x67\x70\x64"
+FOURCC_SIDX="\x73\x69\x64\x78"
+FOURCC_SINF="\x73\x69\x6e\x66"
+FOURCC_SKIP="\x73\x6b\x69\x70"
+FOURCC_SMHD="\x73\x6d\x68\x64"
+FOURCC_SOUN="\x73\x6f\x75\x6e"
+FOURCC_SSIX="\x73\x73\x69\x78"
+FOURCC_STBL="\x73\x74\x62\x6c"
+FOURCC_STCO="\x73\x74\x63\x6f"
+FOURCC_STSC="\x73\x74\x73\x63"
+FOURCC_STSD="\x73\x74\x73\x64"
+FOURCC_STSS="\x73\x74\x73\x73"
+FOURCC_STSZ="\x73\x74\x73\x7a"
+FOURCC_STTS="\x73\x74\x74\x73"
+FOURCC_STYP="\x73\x74\x79\x70"
+FOURCC_TENC="\x74\x65\x6e\x63"
+FOURCC_TFDT="\x74\x66\x64\x74"
+FOURCC_TFHD="\x74\x66\x68\x64"
+FOURCC_TKHD="\x74\x6b\x68\x64"
+FOURCC_TRAF="\x74\x72\x61\x66"
+FOURCC_TRAK="\x74\x72\x61\x6b"
+FOURCC_TREX="\x74\x72\x65\x78"
+FOURCC_TRUN="\x74\x72\x75\x6e"
+FOURCC_UDTA="\x75\x64\x74\x61"
+FOURCC_UUID="\x75\x75\x69\x64"
+FOURCC_VIDE="\x76\x69\x64\x65"
+FOURCC_VMHD="\x76\x6d\x68\x64"
+FOURCC_WIDE="\x77\x69\x64\x65"