Sound quality: If you want to hear the difference between higher and lower bit rates

Have you ever wondered about the difference in the sound quality of music at different bit-rates? Can you hear the difference?
If you listen to 64kbps and 28kbps (either wma or mp3), you'll hear the great difference. However, if you listen to 28kbps and 92kbps (either wma or mp3), you'll find that there is little or no difference (to me, that is).
collegeboy wrote:
We all know that wma 28kbps sounds just as good as wma 320kb
ps.
the reason i and you go higher than 28 is because where able to. you can deny all you want.
If you want to experience better sound quality at higher bit-rates, the best thing to do is to listen to the music at a quiet place. This may sound like lame advise, but it really works. Try 320kbps for the best results. You'll be able to hear minor details you never had before.

SSR wrote:
Wayyyyyy back when I first started encoding MP3s I was using 28 with an inferior encoder. At the time I couldn't spot the difference, but now the difference is stark. Particular types of music (and more specifically instruments and combinations) do emphasise it though.
Actually, you cannot hear the difference when the background noise is loud, or example, public transport. I suggest that one uses a noise cancellation headset. $$$

Similar Messages

Would you please summarize what the difference between tc and alv?

hi, experts,
would you please summarize what the difference between table control and alv base on the function and usage practice.
for example, as i know:
1.edit
tc: can edit in the same screen and save.
alv: pop up a sub screen to let user edit, so this is unconvenient.
2.functional button
alv: can have many functional button as default ,eg. sort, summary and so on
tc: developers must implements by himself.
3.color
alv: can have and change color
tc: cann't changed color
some client may required the data displayed in alv and edit in tc ,such as example BCALV_EDIT_02.
above are my idea, experts, would you give me some comments on my opinion and summarize what the difference between those two components? i should make it clear in order to consult the UI with my client.hunger for your advice, thanks!
Message was edited by:
liu shaochang

ALV Grid is basically used for display puropse. It is more user friendly. There are arious features ( such as coloring, sorting, saving to a local file, sedning by mail etc. ) These featurs make ALV Grid a very good option to display the data .
However , the table control is not only used to display data take from the database table, but also you can do operation such as deletion of data from database table, insertion of data into the database table and updation also. Yeah it has not got the various features whihc ALV has.
So table control and ALV Grid , if you are just using for display purpose, then ALV Grid is a better option due to its layout and attractive features. But if you want to do the database operations other than display, table control can be used.
As far as execution is concerned, I think ALV Grid is faster.
ALV grid control is faster when compared to Table control. But the comaprision is Negligible .
One of the major differences comes in taking of line items - ALV has an advantage over Table Control when it comes to update database from it.Table control only allows maximum of 999 records at a time where as this limitation is not there in ALV.
Also,a main feature of ALV Grid is that it contains a standard set of functions. These functions extend beyond the functions of a table control.
These two UI elements require different keyboard navigation, with ALV Grid being more user-friendly.
An application can display table data in ALV Grid or in a table control. In some applications you can choose between displaying and editing data in either ALV Grid or a table control. If a configurable button () appears in the right upper corner of the table, it is a table control.
Basically ALV is a way to display the output and Table Control is designed in screen painter through which you can get entries in Table Control, can delete some records etc for further processing and its not use only for Display.
ALV is Application List viewer:-
Sap provides a set of ALV (ABAP LIST VIEWER) function modules which can be put into use to embellish the output of a report. This set of ALV functions is used to enhance the readability and functionality of any report output. Cases arise in sap when the output of a report contains columns extending more than 255 characters in length.
In such cases, this set of ALV functions can help choose selected columns and arrange the different columns from a report output and also save different variants for report display. This is a very efficient tool for dynamically sorting and arranging the columns from a report output.
TABLE CONTROL:-
ABAP offers two mechanisms for displaying and using table data in a screen. These mechanisms are table controls and step loops. Table controls and step loops are types of screen tables you can add to a screen in the Screen Painter.

What is the difference between lap and oltp

HI experts, I want to know the difference between OLAP and OLTP and why OLTP cannot be used in bw instead of OLAP? Need realtime anwsers please!!!!!!!!!!

hi navin...
Online transactional processing (OLTP) is designed to efficiently process high volumes of transactions, instantly recording business events (such as a sales invoice payment) and reflecting changes as they occur.
Online analytical processing (OLAP) is designed for analysis and decision support, allowing exploration of often hidden relationships in large amounts of data by providing unlimited views of multiple relationships at any cross-section of defined business dimensions.
OLTP databases are typically input sources for data warehouses or data marts. The data warehouse in turn is the typical source of data for an OLAP database. The value in an OLAP database is that many complex calculations and predefined queries are preprocessed and results are stored and are available via an OLAP exploitation application allowing quick access to cross-sections of business data. Rapid access to the aggregate information across defined business dimensions allows quick navigation and understanding of relationships.
The challenge is to find a solution that will both supply the necessary functionality while addressing the technical considerations of your organization. Some other important considerations include choosing technologies that can leverage existing investments in both hardware and software, and are open and integrated so that your applications are adaptable. This ensures flexibility and agility to meet future business demands.
There are several different modeling techniques. Snowflake and star schemas are just two of many choices. Deciding the best approach for your situation will depend on several factors, most importantly understanding the business issue, the users and their information needs. There is a wealth of information available, including courses, texts and guidelines on this subject alone
OLAP systems organize data in a multidimensional model that is suitable for decision support. OLAP is the analytical counterpart of OLTP, or Online Transactional Processing. SAP's BW is an OLAP system
The Impact of the OLAP/OLTP Cultural Conflict on Data Warehousing....check this link....
http://www.georgetown.edu/users/allanr/Impact.pdf
also check...
http://expertanswercenter.techtarget.com/eac/knowledgebaseAnswer/0,295199,sid63_gci977813,00.html
The big difference when designing for OLAP versus OLTP is rooted in the basics of how the tables are going to be used. I'll discuss OLTP versus OLAP in context to the design of dimensional data warehouses. However, keep in mind there are more architectural components that make up a mature, best practices data warehouse than just the dimensional data warehouse.
Corporate Information Factory, 2nd Edition by W. H. Inmon, Claudia Imhoff, Ryan Sousa
Building the Data Warehouse, 2nd Edition by W. H. Inmon
With OLTP, the tables are designed to facilitate fast inserting, updating and deleting rows of information with each logical unit of work. The database design is highly normalized. Usually and at least to 3NF. Each logical unit of work in an online application will have a relatively small scope with regard to the number of tables that are referenced and/or updated. Also the online application itself handles the majority of the work for joining data to facilitate the screen functions. This means the user doesn't have to worry about traversing across large data relationship paths. A heavy dose of lookup/reference tables and much focus on referential integrity between foreign keys. The physical design of the database needs to take into considerations the need for inserting rows when deciding on physical space settings. A good book for getting a solid base understanding of modeling for OLTP is The Data Modeling Handbook: A Best-Practice Approach to Building Quality Data Models by Michael C. Reingruber, William W. Gregory.
Example: Let's say we have a purchase oder management system. We need to be able to take orders for our customers, and we need to be able to sell many items on each order. We need to capture the store that sold the item, the customer that bought the item (and where we need to ship things and where to bill) and we need to make sure that we pull from the valid store_items to get the correct item number, description and price. Our OLTP data model will contain a CUSTOMER_MASTER, A CUSTOMER_ADDRESS_MASTER, A STORE_MASTER, AN ITEM_MASTER, AN ITEM_PRICE_MASTER, A PURCHASE_ORDER_MASTER AND A PURCHASE_ORDER_LINE_ITEM table. Then we might have a series of M:M relationships for example. An ITEM might have a different price for specific time periods for specific stores.
With OLAP, the tables are designed to facilitate easy access to information. Today's OLAP tools make the job of developing a query very easy. However, you still want to minimize the extensiveness of the relational model in an OLAP application. Users don't have the wills and means to learn how to work through a complex maze of table relationships. So you'll design your tables with a high degree of denormalization. The most prevalent design scheme for OLAP is the Star-Schema, popularized by Ralph Kimball. The star schema has a FACT table that contains the elements of data that are used arithmatically (counting, summing, averaging, etc.) The FACT Table is surrounded by lookup tables called Dimensions. Each Dimension table provides a reference to those things that you want to analyze by. A good book to understand how to design OLAP solutions is The Data Warehouse Toolkit: Practical Techniques for Building Dimensional Data Warehouses by Ralph Kimball.
Example: let's say we want to see some key measures about purchases. We want to know how many items and the sales amount that are purchased by what kind of customer across which stores. The FACT table will contain a column for Qty-purchased and Purchase Amount. The DIMENSION tables will include the ITEM_DESC (contains the item_id & Description), the CUSTOMER_TYPE, the STORE (Store_id & store name), and TIME (contains calendar information such as the date, the month_end_date, quarter_end_date, day_of_week, etc).
Database Fundamentals > Data Warehousing and Business Intelligence with Mike Lampa
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hope it helps...

What is the difference between procedure and function?

Hi,
i want to know the difference between procedure and function.
Also, i want to know types(if they exists) of procedures and functions .
Regards

Also, please try and use the SEARCH functionality offered by the forum, it's always possible someone has asked the question before you.
Functions vs Stored Procedures
Is one such instance.

What is the difference between form6i and form10g

Respected Guru's,
I actually want to know the difference between form6i and form 10g.
Is it bad or good to work on form 6i as compare to form 10g.
plez help me.

The biggest difference is between 6i and 10g is that 6i is client-server and 10g is Webforms(although you can run 6i forms as web).
It's always best to use the latest version: new features, solved bugs and of course support wise.

What is the Difference Between Adapter and Proxy

Hi Master,
I want to know the Difference Between Adapters and Proxies.
And when we are using proxies and Adapters....
Regards,
SReddy

Adapters are part of the Adapter Framework. Adapters provide the technical connectivity to enable the integration of SAP and non-SAP applications through XIs Integration Engine.Again, Adapters are used for connectivity from and to external systems with XI that cannot communicate via proxies.Adapters are only required in SAP systems older than 6.20 and external systems.
Systems based on 6.20or higher can communicate directly with proxies.
The literal definition of a proxy is an object / process authorized to act for another; an agent or a substitute. In simpler terms, proxies in the XI context are objects used to encapsulate the creation (from a sender system) or parsing of XML (at a receiver system) as well as the communication with the relevant runtime components required to send or receive those messages.
Proxies are generated from Message Interface in IR.
The Proxy Runtime controls these objects / processes, and can itself be controlled by the applications it communicates with. The Proxy Runtime currently has the following components available: 1. ABAP Proxy Runtime Communication using XI or Web Services a. Web Service Runtime 2. Java Proxy Runtime Communication using XI (J2EE) The objects that the Proxy Runtime then controls are created via Proxy Generation, for both ABAP and Java. In the following sections a client proxy is used by an application to send messages outside of the system it resides in (normally to the IS in this context). Conversely, a server proxy is used by an application to receive messages from sources outside itself (again, normally the IS in this context).

What's the differences between rsp4 and rsp4+

I want to know the differences between rsp4 and rsp4+

According to the included URL, there is not a big deal of difference between the two devices. Here's a quote:
The RSP4+ is an enhanced version of the RSP4 with larger default program memory (64 MB), Error Correction Code (ECC) memory protection, and compatibility with Cisco IOS® Software releases that support the current RSP4. This additional functionality is included with no increase in price, further enhancing the value of Cisco 7500 Series routers.
http://www.cisco.com/en/US/partner/products/hw/routers/ps359/prod_bulletin09186a00800886e1.html
Hope this helps,

I want to know the difference between iphoto master folder and previews folder

I want to know the difference between iphoto library master folder and previews folder.. my pictures is stored in master but part of them is also copied into previews.. it occupied too much space.. if I can't change anything in iphoto library, any way to save the space for iphoto? 70G for almost 15,000 pictures, is it reasonable?
i use mac book pro, ilife 11..

70GB for 15,000 photos is reasonable, yes, if the photo files are large.
DO NOT meddle with the contents of your iPhoto Library in any other way than using the commands available in the iPhoto application. What appear to be duplicate files stored in different parts of the library are NOT duplicates, and if you attempt to save space by deleting things in the Finder, you will wreck your library and land in a world of trouble.

What is the difference between Firefox and Firefox os please. I have a Samsung galaxy s3 mini what one would you recommend would be better for my phone

What is the difference between Firefox and Firefox os, and what one is better for the Samsung galaxy s3 mini, Please could you recommend which one is the best and most suitable for my phone please. Many thanks Michelle Petch

Thank you for your question.
Firefox is basically a browser.And Firefox OS is an Operating System.You can install Firefox in your SGS3 just like an android application.But if you want Firefox operating system on it. then you have to flash the ported Firefox OS on your device. Then it will be a completely different standalone operating system.you cannot install android applications on it.
To read more technical difference read:
Firefox OS:
http://en.wikipedia.org/wiki/Firefox_OS
Firefox Browser:
http://en.wikipedia.org/wiki/Firefox
Hope this clears your query.Thank you

I want to know the difference between Days column and Day1 Column

Hi All,
I used this query:
SELECT to_char(return_date_time,'dd/mon/yyyy hh24:mi:ss') Test,
DECODE ('I', 'I', DECODE (1, NULL, NULL, 0, NULL, SYSDATE + 1)) Days,
DECODE ('I', 'I', SYSDATE + 1) Day1
FROM fm_curr_locn
WHERE patient_id = 'DU00002765'
output:
Test
Days
Day1
26/oct/2013 00:00:00
26-OCT-13
10/26/2013 3:06:59 PM
I want to know the difference between Days column and Day1 column and why the days column didnt show the time
Please anyone help.....
Regards
Shagar M

Pleiadian wrote:
It is the decode statement that is doing this.
The format of decode is:
decode(expression, search1, result1, search2, result2, searchn, resultn, default)
All result fields must be of the same datatype and will be of the datatype of the first result (result1 in this example)
In your example (the decode for the field Days) the first result is a NULL. I suspect (gurus? anyone?) that Oracle will use the varchar2 overload of the decode statement, and the date field will be converted to varchar2 using your NLS_DATE_FORMAT settings.
In the second decode statment (Day1) the first result is of datatype date, so the result of the decode statement will be a date field (and will be parsed as such by your sql development tool)
I agree, as NULL is the first result returned the datatype is undetermined, so Oracle is picking VARCHAR2 over others, and causing an implicit datatype conversion on the resultant date value, whereas the other which is returned as a date will use the local settings of the client tool being used.
I can replicate the 'issue' in Toad, and it's rectified if we cast the first returned value of the decode statement...
SELECT DECODE ('I', 'I', DECODE (1, NULL, CAST(NULL AS DATE), 0, NULL, SYSDATE + 1)) Days,
DECODE ('I', 'I', SYSDATE + 1) Day1
FROM dual

Whats the difference between Fatal1ty and Fatal1ty USB heads

Whats the difference between Fatal1ty and Fatal1ty USB headset? What is the $30 price difference for other than a USB connection?
Also, what is the advantage to using the USB port?
Still trying to decide on which headset to buy. I will be using these mainly for gaming and some music. Although i'm not real picky when it comes to music quality. Even considered the HS-1200 wireless. Which headset of these 3 has the best sound quality and better quality?
Message Edited by iowabucks on 10-20-2008 07:54 AM
Message Edited by iowabucks on 10-20-2008 08:10 AM

Any USB sound related item is going to use system resources instead of the non usb version. The non usb version uses the resources of the sound card and not system resources. So you should get cleaner sound with the non usb version.
But, be aware creatives tech support is not the best in the world. Keep that in mind when buying a product from them.

What's the difference between 2nd and 3rd generation

PLEASE HELP! New Apple user and looking to purchase a used 2nd or 3rd generation ipod touch.
what's the difference between 2nd and 3rd generation?
apparently I am told that the 2nd gen does not have the capabilities of listening without headphone? and the 3rd gen does??

Hi maximumslowness - (great name),
The 2nd gen Touch has one internal speaker, so you can listen to it, (both left and right channels) without headphones.
However - it's a small single speaker and it is not very loud. It's not designed for quality listening (neither is the speaker on the 3rd gen as far as I know) and probably will not be adequate if there is a lot of background noise nearby.
One option is to drop the iPod (not literally!) into an iPod Docking station so that the sound can play out through a self-contained mains-powered amplified speaker, which will also charge your iPod. There are many on the market. On the bottom of the iPod is the 30-pin dock connector which can be used to feed the audio to a docking station. Another option is simply to use a cable to connect from the headphone socket to the audio input on any amplifier.
Yet another is to plug in a small fold-up style speakers, such as
http://www.amazon.co.uk/Portable-Folding-Speakers-iPods-Players/dp/B000A1QKNU/re f=sr_1_84?ie=UTF8&qid=1332326622&sr=8-84
or http://www.amazon.co.uk/Generation-Capsule-iPhone-Laptop-Speaker/dp/B002XNO7FQ/r ef=sr_1_6?ie=UTF8&qid=1332326656&sr=8-6
I've no idea how good the sound is, you'll have to judge that for yourself. The links are both to a UK store, but most countries will have a similar option.
I do not recieve any form of payment or compensatiion for the above links.
Message was edited by: the fiend

What's the Difference Between OLAP and OLTP?

HI,
What's the difference between OLAP and OLTP ? and which one is Best?
-Arun.M.D

Hi,
The big difference when designing for OLAP versus OLTP is rooted in the basics of how the tables are going to be used. I'll discuss OLTP versus OLAP in context to the design of dimensional data warehouses. However, keep in mind there are more architectural components that make up a mature, best practices data warehouse than just the dimensional data warehouse.
Corporate Information Factory, 2nd Edition by W. H. Inmon, Claudia Imhoff, Ryan Sousa
Building the Data Warehouse, 2nd Edition by W. H. Inmon
With OLTP, the tables are designed to facilitate fast inserting, updating and deleting rows of information with each logical unit of work. The database design is highly normalized. Usually and at least to 3NF. Each logical unit of work in an online application will have a relatively small scope with regard to the number of tables that are referenced and/or updated. Also the online application itself handles the majority of the work for joining data to facilitate the screen functions. This means the user doesn't have to worry about traversing across large data relationship paths. A heavy dose of lookup/reference tables and much focus on referential integrity between foreign keys. The physical design of the database needs to take into considerations the need for inserting rows when deciding on physical space settings. A good book for getting a solid base understanding of modeling for OLTP is The Data Modeling Handbook: A Best-Practice Approach to Building Quality Data Models by Michael C. Reingruber, William W. Gregory.
Example: Let's say we have a purchase oder management system. We need to be able to take orders for our customers, and we need to be able to sell many items on each order. We need to capture the store that sold the item, the customer that bought the item (and where we need to ship things and where to bill) and we need to make sure that we pull from the valid store_items to get the correct item number, description and price. Our OLTP data model will contain a CUSTOMER_MASTER, A CUSTOMER_ADDRESS_MASTER, A STORE_MASTER, AN ITEM_MASTER, AN ITEM_PRICE_MASTER, A PURCHASE_ORDER_MASTER AND A PURCHASE_ORDER_LINE_ITEM table. Then we might have a series of M:M relationships for example. An ITEM might have a different price for specific time periods for specific stores.
With OLAP, the tables are designed to facilitate easy access to information. Today's OLAP tools make the job of developing a query very easy. However, you still want to minimize the extensiveness of the relational model in an OLAP application. Users don't have the wills and means to learn how to work through a complex maze of table relationships. So you'll design your tables with a high degree of denormalization. The most prevalent design scheme for OLAP is the Star-Schema, popularized by Ralph Kimball. The star schema has a FACT table that contains the elements of data that are used arithmatically (counting, summing, averaging, etc.) The FACT Table is surrounded by lookup tables called Dimensions. Each Dimension table provides a reference to those things that you want to analyze by. A good book to understand how to design OLAP solutions is The Data Warehouse Toolkit: Practical Techniques for Building Dimensional Data Warehouses by Ralph Kimball.
Example: let's say we want to see some key measures about purchases. We want to know how many items and the sales amount that are purchased by what kind of customer across which stores. The FACT table will contain a column for Qty-purchased and Purchase Amount. The DIMENSION tables will include the ITEM_DESC (contains the item_id & Description), the CUSTOMER_TYPE, the STORE (Store_id & store name), and TIME (contains calendar information such as the date, the month_end_date, quarter_end_date, day_of_week, etc).
Database Fundamentals > Data Warehousing and Business Intelligence with Mike Lampa
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Your question may have already been answered! Browse or search more than 25,000 question and answer pairs from more than 250 TechTarget industry experts.

Questions about the differences between Arch and Chakra.

I'm trying to decide whether to install Arch or Chakra on my laptop. Currently, I'm running Arch on my desktop and Windows 7 on my laptop (which I plan to overwrite). My skill level with GNU/Linux is somewhat intermediate – noobs refer to me as an expert, experts refer to me as a noob. If it matters, I'm a KDE user and primarily use my computers for web browsing and python development. Anyway, I just wanted to get an objective opinion on the differences between Arch and Chakra. I have a few points that stand out to me, but I welcome any input.
-Stability
I started my journey into GNU/Linux with Debian back in 2009 due to it's stability. I really disliked Debian's ancient software and considered moving my system to Unstable. While doing some googling about Debian Unstable, I stumbled across Arch – it was love at first sight. I've been an Arch user ever since. I love the bleeding edge software, and haven't had any major problems since I originally installed it. However, every time I run a system update I cringe a little. While Arch hasn't broken on me yet, I've read plenty of horror stories and it makes me uneasy. I understand that Chakra is a mix between a point and rolling release model. Is it any more or less stable than Arch? I know there are other distrobutions out there, but I'm in love with the Arch philosophy.
-Security
Pretty self-explanatory, but is there any difference in security between the two?
-AUR
As much as I love Arch, I wouldn't be able to stand it if it weren't for the massive collection of software available in the AUR. While I'm perfectly capable of compiling software myself, I prefer to use a command like tool like yaourt to manage my software. I understand that Chakra doesn't officially support the AUR and that they have their own user repository. Seeing as Chakra is still relatively new, is it lacking? Will I miss the AUR as a Chakra user?
-Repositories
Is there much difference in the official repositories between the two distrobutions?

avonin wrote:
I'm trying to decide whether to install Arch or Chakra on my laptop. ... I'm a KDE user ... I just wanted to get an objective opinion on the differences between Arch and Chakra..
-Stability...
-AUR...
-Repositories...
My take on Chakra is that it's the same as Arch with different developers. They use pacman. They have a different and rather nice build system for their developers. They're doing a good job, but I'd hate to give up the services of Allan McRae who must work full time keeping the Archlinux core and toolchain up to date. Chakra devs probably piggy-back off his work.
As for "semi" rolling: I don't see Chakra as having a stable core. A stable core sounds attractive, it would be like NetBSD which has a very stable core Unix operating system with apps added via pkgsrc. But Chakra's core and toolchain is at the same version levels as Archlinux most of the time and are no more tested and stabilized than ours. Their core packages are updated piecemeal just like ours; there is no stable core that is released as a unit (afaik). Today Chakra has gcc 4.7 / glibc 2.15 just like ours. Their kernel is a little more stable: they're using udev 181 / linux 3.2.8 while Arch is on udev 182 / linux 3.3.7. They are more conservative in upgrading xorg and the video drivers than Arch. For example, today they're on xorg-server 1.10.4 / intel video 2.17 while Arch is up-to-the-bleeding-edge-minute with xorg-server 1.12.1.902 and intel video 2.19. Yeah, I would consider Chakra to be a little more "stable" than Arch mainly because of their relaxed pace in changing the kernel and the xorg stuff.
Most of the patches that I look at for Arch packages (I build my system entirely from source and try to build monthly releases for myself) are needed because we use more recent core packages like glib2/glibc/gcc than the developers of higher level stuff like qt. Chakra is in the same situation. We're on the front of the wave
The Chakra CCR is compatible with the Arch AUR and mainly draws from AUR (an AUR buildscript will usually work fine on a Chakra system -- they just add one or two additional info fields.) With a little effort you could get any package installed on a Chakra system that is available on Arch.
Last edited by sitquietly (2012-05-24 20:43:58)

What is the difference between exists and in

hi all
if i have these queries
1- select ename from emp where ename in ( select ename from emp where empno=10)
and
2- select ename from emp where exists ( select ename from emp where empno=10)
what is the difference between exists and in is that only when i use in i have to bring the field name or what.... i mean in a complex SQL queries is it will give the same answer
Thanks

You get two entirely different result sets that may be the same. Haah! What do I mean by that.
SQL> select table_name from user_tables;
TABLE_NAME
BAR
FOO
2 rows selected.
SQL> select table_name from user_tables where table_name in (select table_name from user_tables where table_name = 'FOO');
TABLE_NAME
FOO
1 row selected.
SQL> select table_name from user_tables where exists(select table_name from user_tables where table_name = 'FOO');
TABLE_NAME
BAR
FOO
2 rows selected.So, why is this? the WHERE EXISTS means 'if the next is true', much like where 1=1 being always true and 1=2 being always false. In this case, where exists could be TRUE or FALSE, depending on the subquery.
WHERE EXISTS can be useful for something like testing if we have data, without actually having to return columns.
So, if you want to see if an employee exists you might say
SELECT 1 FROM DUAL WHERE EXISTS( select * from emp where empid = 10);
If there is a row in emp for empid=10, then you get back 1 from dual;
This is what I call an 'optimistic' lookup because the WHERE EXISTS ends as soon as there is a hit. It does not care how many - only that at least one exists. It is optimistic because it will continue processing the table lookup until either it hits or reaches the end of the table - for a non-indexed query.

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