readme

realmedia解压源码

libreal

This is a straightforward implementation of the RealMedia spec.
Just use make to compile it, and put the library in /usr/local/lib
and libreal.h in /usr/local/include or wherever.

A realmedia file is split into several sections of chunks and
subchunks.

All the IO functions in this library must be passed a file descriptor,
which can be a file or a pipe.

You can read a chunk by calling rm_read_chunk(int fd, RM_Chunk *chunk),
where *chunk is a pointer to a variable of type RM_Chunk (defined in
libreal.h) and fd is the file descriptor. It's then your responsibility
to deal with it however you want, depending on the object id, which can
be one of:

	FILE_HEADER_ID
	PROPERTIES_ID
	MEDIA_PROPERTIES_ID
	CONTENT_HEADER_ID
	DATA_HEADER_ID
	INDEX_HEADER_ID

Data Headers and Index Headers are followed by sub-chunks of type
Media Packet Header and Index Record respectively. To read these
use rm_read_media_packet_header(int fd, RM_Media_Packet_Header *header)
and rm_read_index_record(int fd, RM_Index_Record *rec).

Writing is the same except the functions are rm_write_* instead of
rm_read_*.

All functions return 0 on success and non-zero on failure. Sometimes they
print error messages to stderr.

By default libreal ignores the version field of chunks, this usually
doesn't cause too many problems. If you want it to return an error for
a non-zero version (I have only implemented version 0) then comment out
the appropriate line in the makefile.

For information on the various fields and chunk types, take a look at
libreal.h

I have included a test program which reads in a realmedia file called
"test.rm" in the current directory, parses it and uses librm to write
the file out to "test-out.rm". NOTE: the strings in media properties
and content description are NOT null-terminated. test.c assumes that
they are. It may crash, or print garbage after the end of the string.

Leo Howell