How can I read the file header of mov file

At first you need the file format specification. See QuickTime File Format - Wikipedia[^] for an overview and history and the QuickTime File Format Specification[^] for the reference.

According to the reference, QuickTime files use "atoms" to specify data blocks. Each atom begins with a 4 byte size field followed by a type field. So you can step through the file reading the size and type, optionally process the following data and resume at the next atom by adding the size to the file position.

To read the file use any C/C++ file library functions that support seeking (e.g. fopen(), fread(), fseek(), fclose()).

If you need further processing of QuickTime files I suggest to use a library rather than doing it yourself. Examples may be GStreamer[^] and FFmpeg[^].

uint32_t atom_size;
// Field has 4 characters. Use 5 byte NULL terminated buffer here
//  to allow using strcmp().
char atom_type[5] = "xxxx";
FILE *f = fopen(fileName, "rb");
fread(&atom_size, sizeof(atom_size), 1, f);
fread(atom_type, 4, 1, f);
// Seek to next atom or read atom into allocated buffer
fseek(f, atom_size, SEEK_CUR);