*
* @param buffer Memory block for input/output operations via AVIOContext.
* The buffer must be allocated with av_malloc() and friends.
+ * It may be freed and replaced with a new buffer by libavformat.
+ * AVIOContext.buffer holds the buffer currently in use,
+ * which must be later freed with av_free().
* @param buffer_size The buffer size is very important for performance.
* For protocols with fixed blocksize it should be set to this blocksize.
* For others a typical size is a cache page, e.g. 4kb.