two segment fault in Ap4SampleDescription.h in when running mp42ts

[92wyunchao]

POC to trigger the two bugs.
poc.zip

(1)mp42ts poc1 out.ts
ASan:
==97945==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x000000537e60 bp 0x7ffc715da790 sp 0x7ffc715da5e0 T0)
#0 0x537e5f in AP4_SampleDescription::GetType() const /home/s2e/1/Bento4-master/Source/C++/Core/Ap4SampleDescription.h:127
#1 0x537e5f in AP4_Mpeg2TsVideoSampleStream::WriteSample(AP4_Sample&, AP4_DataBuffer&, AP4_SampleDescription*, bool, AP4_ByteStream&) /home/s2e/1/Bento4-master/Source/C++/Core/Ap4Mpeg2Ts.cpp:524
#2 0x529953 in WriteSamples(AP4_Mpeg2TsWriter&, AP4_Track*, SampleReader*, AP4_Mpeg2TsWriter::SampleStream*, AP4_Track*, SampleReader*, AP4_Mpeg2TsWriter::SampleStream*, unsigned int) /home/s2e/1/Bento4-master/Source/C++/Apps/Mp42Ts/Mp42Ts.cpp:305
#3 0x529953 in main /home/s2e/1/Bento4-master/Source/C++/Apps/Mp42Ts/Mp42Ts.cpp:620
#4 0x7fa66bec782f in __libc_start_main /build/glibc-Cl5G7W/glibc-2.23/csu/../csu/libc-start.c:291
#5 0x4527f8 in _start (/home/s2e/1/Bento4-master/cmakebuild/mp42ts+0x4527f8)

(2)mp42ts poc2 out.ts
ASan:
==104133==ERROR: AddressSanitizer: SEGV on unknown address 0x00000000000c (pc 0x000000536e46 bp 0x7ffed568fc30 sp 0x7ffed568fb00 T0)
#0 0x536e45 in AP4_SampleDescription::GetFormat() const /home/s2e/1/Bento4-master/Source/C++/Core/Ap4SampleDescription.h:128
#1 0x536e45 in AP4_Mpeg2TsAudioSampleStream::WriteSample(AP4_Sample&, AP4_DataBuffer&, AP4_SampleDescription*, bool, AP4_ByteStream&) /home/s2e/1/Bento4-master/Source/C++/Core/Ap4Mpeg2Ts.cpp:412
#2 0x529b1e in WriteSamples(AP4_Mpeg2TsWriter&, AP4_Track*, SampleReader*, AP4_Mpeg2TsWriter::SampleStream*, AP4_Track*, SampleReader*, AP4_Mpeg2TsWriter::SampleStream*, unsigned int) /home/s2e/1/Bento4-master/Source/C++/Apps/Mp42Ts/Mp42Ts.cpp:294
#3 0x529b1e in main /home/s2e/1/Bento4-master/Source/C++/Apps/Mp42Ts/Mp42Ts.cpp:620
#4 0x7f3ffb20582f in __libc_start_main /build/glibc-Cl5G7W/glibc-2.23/csu/../csu/libc-start.c:291
#5 0x4527f8 in _start (/home/s2e/1/Bento4-master/cmakebuild/mp42ts+0x4527f8)