Mobile Phones : Audio And Video Formats
& Single Sim V/S Dual Sim Phone
4.8. Audio/Video
formats in mobile phones
1. MPEG (Motion Picture Experts Group):It
is wide range of formats for digital audio and video files.
The most common among them are MPEG-4 (for video) and MP3
(for audio). An audio storage protocol that stores music
in a compressed format with very little loss in sound quality.
MP3 is the most common MPEG format for audio files. MP3
files can be played using the music player of the mobile
phone or set as a ringtone.
2. MPEG-4 is one of the latest video/audio
compression method standardized by MPEG group, designed
specially for low-bandwidth (less than 1.5MBit/sec bitrate)
video/audio encoding purposes.MPEG-4 is designed to deliver
DVD-quality video (MPEG-2) at lower data rates and smaller
file sizes.
The official filename extension for MPEG-4 Part 14 files
is .mp4, thus the container format is often referred to
simply as MP4. However various file extensions are also
commonly used to indicate the content inside the MP4 container:
MPEG-4 files with audio and video generally use
the standard .mp4 extension.
Audio-only MPEG-4 files generally have an .m4a extension.
This is especially true of non-protected content.
MPEG-4 files with audio streams encrypted by FairPlay
Digital Rights Management as sold through the iTunes
Store use the .m4p extension.
Audio book and podcast files, which also contain
metadata including chapter markers, images, and hyperlinks,
can use the extension .m4a, but more commonly use the
.m4b extension. An .m4a audio file cannot "bookmark"
(remember the last listening spot), whereas .m4b extension
files can.
Raw MPEG-4 Visual bitstreams are named .m4v.
Mobile phones use 3GP, a simplified version of MPEG-4
Part 12 (MPEG-4/JPEG2000 ISO Base Media file format),
with the .3gp and .3g2 extensions. These files also
store non-MPEG-4 data (H.263, AMR, TX3G).
3. AAC (Advanced Audio Coding):AAC is
a file format for storing digital audio. It's commonly used
for storing music on the Internet, PCs and portable music
players and phones. It is similar to MP3, but it was designed
to be its successor and offers better quality and smaller
file sizes. It also supports DRM, which enforces copyright.
AAC+ and AAC++ are newer versions of the standard.
4. AIFF (Audio Interchange File Format):
It is a file format developed by Apple and company to store
audio information. This is a really old file format compared
to MP3 and is very similar to the WAV file format developed
by Microsoft. The most major difference between the AIFF
and MP3 is compression. AIFF does not do compression while
MP3 does.
5. 3GP and 3G2: are multimedia container
formats used for the delivery and playback of audio/video files
over high-speed wireless networks, especially mobile cell phones.
Developed and defined by the 3rd Generation Partnership Project
and 3rd Generation Partnership Project 2 respectively, they
are built to contain various types of compressed data. Both
the 3GP and 3G2 file formats were especially designed so as
to decrease the bandwidth and storage requirements in order
to accommodate mobile cell phones. Structurally, they are based
on the ISO file format defined in ISO/IEC 14496-12-MPEG-4 Part
12. The 3GP file can store video streams in MPEG-4 Part 2 (also
called H.263) and MPEG-4 Part 10 (AVC/H264) formats, and audio
streams in AAC-LC, HE-AAC v1, HE-AAC v2, AMR-NB, , and AMR-WB+.
The 3G2 file, on the other hand, can store all the video streams
as those of 3GP. As for the audio streams, it can store the
same as those of 3GP, with the exception of HE-AAC v2 and AMR-WB,
which it cannot store.
Instead, it can store EVRC, EVRC-B, EVRC-WB, QCELP, SMV,
and VMR-WB audio streams. The 3G2 Timed Text specifications
are also more advanced than those of the 3GP.
3GP and 3G2 files can be opened on most 3G enabled mobile
phones, and some 2G and 4G devices as well. File size, memory,
and resolution limits may vary from phone to phone. When transferred
on the computer, the files should be converted to more popular
video formats.
4.9. Single SIM Phones
V/s Dual SIM phone
SIM stands for Subscriber Identity Module card that which
is the key for the portability of your mobile. The SIM from
a mobile service provider will be able to secure your data and
identify yourself over the networks card stores all the connection
data and identification numbers you need to access a particular
service provider.
Single SIM mobile phones are those that use only a single
SIM at a time, and dual SIM mobile phones are those that can
operate on two SIM cards. In dual SIM card mobile phones, if
one of the SIM card remains inactive while the other one isactive,
then is known as Standby Dual SIM phone, and if both the cards
are active concurrently, then is known as Active Dual SIM mobile
phone.
Advantages of single SIM over dual SIM:
The price charge of a Dual SIM phone goes much higher
than usual, and in comparison, having a basic phone on the
other SIM is much cheaper than having a Dual SIM, which
comes with the disadvantage of paying more.
You will be switching off both the SIM when you want
to switch the mobile off. Therefore, this is much better
two have two single SIM phones, that you have the option
of being on in one when the other goes off, or the battery
goes down in one or the other, you will always be available
in one or the other phone
A dual SIM mobile phone battery must be of larger capacity
than a normal phone. Some phones support two separate batteries
one for each SIM card. While this improves talk and standby
time, second battery certainly adds to the handset weight.
Advantages of dual SIM over single SIM:
The main overall advantage that you get with dual SIM
phone, is the fact that you can have two separate numbers
register for the same phone
Freedom of choice for service providers.
Most dual SIM phones are made to work worldwide, so
long as they are set up for the right type of connection.In
some countries only one type of phone network is present.
That means service providers are only compatible with either
GSM or CDMA. But as long as you have dual SIM cards that
are compatible with that type of signal, you can access
wireless service from just about anywhere in the world,
which is a massive advantage.
A Dual SIM mobile phone is handy for those who often
travel between two countries. They don't have to change
their SIM card while traveling.
The Dual SIM phone also gives peace of mind to those
who dread the thought of being out of a network. It allows
one to have two numbers from two different carriers, which
minimizes the risk of losing the signal bar - if one carrier
signal goes weak there is an option to try the other.
Technological limitations are much lesser in Single
SIM phones.
