fprintf(stderr, "ogg_write_trailer\n") ;
static int ogg_write_trailer(AVFormatContext *avfcontext) {    OggContext *context = avfcontext->priv_data ;    ogg_page og ;    fprintf(stderr, "ogg_write_trailer\n") ;    while(ogg_stream_flush(&context->os, &og)) {	put_buffer(&avfcontext->pb, og.header, og.header_len) ;	put_buffer(&avfcontext->pb, og.body, og.body_len) ;	put_flush_packet(&avfcontext->pb);    }    ogg_stream_clear(&context->os) ;    return 0 ;}