Codec stands for enCOder/DECoder or COmpressor/DECompressor. It is a software or hardware that compresses and decompresses audio and video data streams.
Codec stands for enCOder/DECoder or COmpressor/DECompressor. It is a software or hardware that compresses and decompresses audio and video data streams.
Codec stands for enCOder/DECoder or COmpressor/DECompressor. It is a software or hardware that compresses and decompresses audio and video data streams.
This is the subject slides for the module MMS2401 - Multimedia System and Communication taught in Shepherd College of Media Technology, Affiliated with Purbanchal University.
Audio is an electrical or other representation of sound.
An audio file format is a file format for storing digital audio data on a computer system.
It can be a raw bitstream, but it is usually a container format or an audio data format with a defined storage layer.
Video coding is an essential component of video streaming, digital TV, video chat and many other technologies. This presentation, an invited lecture to the US Patent and Trade Mark Office, describes some of the key developments in the history of video coding.
Many of the components of present-day video codecs were originally developed before 1990. From 1990 onwards, developments in video coding were closely associated with industry standards such as MPEG-2, H.264 and H.265/HEVC.
The presentation covers:
- Basic concepts of video coding
- Fundamental inventions prior to 1990
- Industry standards from 1990 to 2014
- Video coding patents and patent pools.
Audio Compression Techniques
a type of lossy or lossless compression in which the amount of data in a recorded waveform is reduced to differing extents for transmission respectively with or without some loss of quality, used in CD and MP3 encoding, Internet radio.
Dynamic range compression, also called audio level compression, in which the dynamic range, the difference between loud and quiet, of an audio waveform is reduced
This presentation is meant to discuss the basics of video compression like DCT, Color space conversion, Motion Compensation etc. It also discusses the standards like H.264, MPEG2, MPEG4 etc.
This is the subject slides for the module MMS2401 - Multimedia System and Communication taught in Shepherd College of Media Technology, Affiliated with Purbanchal University.
Audio is an electrical or other representation of sound.
An audio file format is a file format for storing digital audio data on a computer system.
It can be a raw bitstream, but it is usually a container format or an audio data format with a defined storage layer.
Video coding is an essential component of video streaming, digital TV, video chat and many other technologies. This presentation, an invited lecture to the US Patent and Trade Mark Office, describes some of the key developments in the history of video coding.
Many of the components of present-day video codecs were originally developed before 1990. From 1990 onwards, developments in video coding were closely associated with industry standards such as MPEG-2, H.264 and H.265/HEVC.
The presentation covers:
- Basic concepts of video coding
- Fundamental inventions prior to 1990
- Industry standards from 1990 to 2014
- Video coding patents and patent pools.
Audio Compression Techniques
a type of lossy or lossless compression in which the amount of data in a recorded waveform is reduced to differing extents for transmission respectively with or without some loss of quality, used in CD and MP3 encoding, Internet radio.
Dynamic range compression, also called audio level compression, in which the dynamic range, the difference between loud and quiet, of an audio waveform is reduced
This presentation is meant to discuss the basics of video compression like DCT, Color space conversion, Motion Compensation etc. It also discusses the standards like H.264, MPEG2, MPEG4 etc.
Multimedia Technologies Introduction Subject
Multimedia Technology introduction - I created these slides for my students to teach CMP 383 Multimedia Technology at Jazan Community College , Jazan University
Unsure of the aspect ratio for your iPhone? Can’t tell a bit rate from a frame rate? At a loss when it comes to lossy and lossless codecs? Don’t worry, we’re here to help.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
State of ICS and IoT Cyber Threat Landscape Report 2024 preview
Codecs
1. Abstract:
In the age of smart phones and internet ready devices, audio/video transport and distribution
has evolved from sharing low quality files to providing high quality mobile device streams, click
to play content, over the air broadcasting, audio distribution in large facilities, and more. Each
medium has several methods of compressing content by means of a codec. This session will
explain which codecs are appropriate for which purposes, common misuse of audio codecs, and
how to maintain audio quality by implementing codecs professionally.
Introduction:
What a codec is?
Codec (enCOder/DECoder or COmpressor/DECompressor): software (or hardware) that
compresses and decompresses audio and video data streams.
The purpose of codecs is to reduce the size of digital audio samples and video frames in order to
speed up transmission and save storage space.
According to Wikipedia, "A codec is a device or program capable of performing encoding and
decoding on a digital data stream or signal." In plain English I'd put it this way: a codec allows
one to read and save audio and video files, often for the purposes of saving space.
The best known example of a codec is MP3. It compresses bulky audio files such as WAV to
much smaller MP3 files.
All codecs involve a tradeoff between the amount of compression and the resultant quality. If
you compress too much the quality loss may become intolerable.
A codec can consist of two components: an encoder and a decoder. The encoder performs the
compression (encoding) function and the decoder performs the decompression (decoding)
function. Some codecs include both of these components and some codecs only include one of
them.
For example, when you rip a song from an audio CD to your computer, the Player uses
the Windows Media Audio codec by default to compress the song into a compact WMA file. When
you play that WMA file (or any WMA file that might be streamed from a website), the Player uses
the Windows Media Audio codec to decompress the file so the music can be played through your
speakers.
Hence A codec is software that is used to compress or decompress a digital media file, such as a
song or video.
Why do we need codecs?
ANS: Because video and music files are large, they become difficult to transfer across the
Internet quickly. To help speed up downloads, mathematical "codecs" were built to encode
("shrink") a signal for transmission and then decode it for viewing or editing. Without codecs,
downloads would take three to five times longer than they do now.
2. The data rate of a video file governs the ability of the target device for playback. Originally CD
drives were only 1X and the data rate for video files had to fall into the limitations of that device
for playback. In order to reach the planned target some concessions had to be made to allow
smooth playback, i.e. smaller frame resolutions, lower frame rates, lower audio rates. This is
where compression comes into play - all these factors gathered together and crammed into a
single stream for playback at the lowered target data rate.
Understanding codecs and compression/decompression is really not that difficult in obvious
information - more compression less picture quality, less compression better picture quality. It is
more difficult to understand how to compress the video in order to achieve the target playback
you desire. There is always a trade-off when it comes to passing video over the web, particularly
when the users have 56K or lower connections. Unless the user has broadband the image has to
suffer in some way. It has to be compressed to lower data rates and frame rates are cut down to
10 or 15fps.
Compression has always had a lot to do with the ability to share video over various connection
speeds through the internet. Full frame resolution NTSC video with CD quality audio
uncompressed has a data rate of nearly 30MB per
second. Even with large amounts of compression that stream would choke over a 56K
connection. Over the years many different types of codecs have been developed in the hope of
achieving better quality video at lower data rates.
This is where MPEG-2 compression outshines all the rest lowering the Megabytes to megabits
and still offering a high quality picture with sound. Unlike many of the non-DV video algorithm's
MPEG-2 does not have sub-format frame ratios.
Most video applications using software based codecs assume a 4:3 ratio and the sub-ratio's
based upon it, i.e. 640x480, 320x240, 160x120,etc. all square pixel ratio's. This is because DV
was not around and analog capture was done in square pixel 4:3 screen ratios. MPEG-2 on the
other hand expects the DV pixel ratio and frame resolution. There is a breaking point with any
codec in relationship to compression - the more the compression the lesser the picture quality.
Naturally the less the compression the better the picture quality.
Lossy or Lossless codecs:
The goal of all codec designers is to maintain audio and video quality while compressing the
binary data further.
Most codecs are LOSSY, in order to get a reasonably small file size. There are LOSSLESS codecs
as well, but for most purposes the almost imperceptible increase in quality is not worth the
considerable increase in data size. The main exception is if the data will undergo more
processing in the future, in which case the repeated lossy encoding would damage the eventual
quality too much.
Examples of Lossy file formats: AAC (Advanced Audio Coding), MP3, Vorbis (filename extension
.OGG), lossy Windows Media Audio (filename extension .WMA)...
Example of Lossless file formats: Apple Lossless (filename extension .m4a), FLAC, Monkey's
Audio (filename extension .APE), Shorten, TTA, lossless Windows Media Audio (filename
extension .WMA), WavPack.
3. Classification of Codecs:
1. Audio Codecs:
In Software, an audio codec is a computer program implementing an algorithm that
compresses and decompresses digital audio data according to a given audio file format or
streaming media audio format. The object of the algorithm is to represent the high-
fidelity audio signal with minimum number of bits while retaining the quality. This can
effectively reduce the storage space and the bandwidth required for transmission of the
stored audio file. Most codecs are implemented as libraries which interface to one or
more multimedia players.
Software Audio Codecs can be classified as:
Non Compression Formats (LPCM, PDM, PAM)
Lossless Formats (ALAC, FLAC, MPEG-4 ALS)
Lossy Formats (Dolby Digital, MP1, MP2, MP3, AAC, WMA)
In hardware, audio codec refers to a single device that encodes analog audio as digital
signals and decodes digital back into analog. In other words, it contains both an Analog-
to-digital converter (ADC) and Digital-to-analog converter (DAC) running off the same
clock. This is used in sound cards that support both audio in and out, for instance.
2. Video Codecs:
A video codec is a combination of hardware and/or software that creates a binary stream
of data that represents the video and audio captured by a camera. Encoders differ from
capture devices primarily in what they are intended to create as output. A capture card
usually creates a binary stream that will be stored as a file. An encoder usually creates a
stream of data that is to be transferred to a second device. This second device has
various names such as set-top box or decoder, but it essentially reverses the process
carried out by the encoder and re-creates the representation of the scene picked up by
the camera.
Video codecs basically do three things. If the camera is analog, they sample the output
signal. The rate at which this is done is referred to as the sampling rate. Each sample is
then converted into a certain number of bits (often 8) during the analog-to-digital
conversion process (A/D). This is called quantization. Finally, the codec must do
compression on the resulting bit stream because it is usually too much information to be
efficiently transmitted.
Video Codecs can be classified as:
Lossless Compression (FFV1, Dirac Lossless, H264 Lossless)
Lossy Compression (H.264/MPEG-4 AVC, AVC, H.263)
Hence, a video codec is software or a device that provides encoding and decoding which
may or may not include the use of video compression and/or decompression for digital
video.
4. 3. Text Codecs
A Text Codec is a function that transforms text into (when encoding) or out of (when
decoding) another kind of representation. Usually, the most human-readable
representation is said to be "decoded".
"Encoders" will turn the (selected or whole) text into something less readable, "Decoders"
try to revert those effects as good as possible.
E.g.: ROT-13, Base64, URI Codecs, Unicode Codecs, Case Encoders, CMML, BiM
Codecs can also be classified into Specialized codecs such as „Speech Codecs‟ which are
designed to deal with the characteristics of voice, while „Audio Codecs‟ are developed for
music. The difference between speech and audio codecs is that speech codecs look for
speech patterns in order to compress the data further.
Codecs may also be able to transcode from one digital format to another; for example, from PCM
audio to MP3 audio.
What’s the difference between decoding, encoding, recoding and
transcoding?
• Decoding
Simply opening and watching video files with a video player (e.g. a DivX decoder for opening
DivX files or a MPEG-1 Decoder for opening a MPEG-1 video file).
• Encoding
Creating a video file in a special format (e.g. DivX, MPEG-2, MPEG-4, ...) - You´ll need a DivX
Encoder in order to be able to create DivX files and a MPEG-2 Encoder in order to be able to
create MPEG-2 videos. You´ll need these encoders for transcoding and recoding video files as
well.
• Recoding
Conversion of a video file which is present in a special format with special attributes in the same
format with different attributes (e.g. 2 h movie with 3000 Kbit/s into 2 h movie with 2000
Kbit/s).
• Transcoding
Conversion of a video file which is present in a special format into another video format (e.g.
DivX in DVD or MPEG-2 in DivX).
5. Understanding Various Video Codecs:
The Video codecs is a method of compression/decompression of video file, video data or
streaming video format. The codecs stands for Coders / Decoders.
There are various kinds of video codecs available. Since these codecs have been implemented by
different algorithms by number of companies; they have different specification and application in
various fields. These video codecs generally complies Industry standards.
The various software video codecs are:
H.264 / MPEG-4 AVC
Mpeg-4
DivX
x264
Real Video
Sorenson
Mpeg-1
Mpeg-2
H.261
H.263
These various Video codecs are technically differentiated from each other based on various
factors which includes compression technology / algorithm, platform supported, sampling, OS
supported etc
One can easily compare the various Video codecs from various websites. But still there is
confusion which codec is the appropriate? However it also depends on application. But
understanding pros & cons of some of these codecs gives us the better information and insight
depth.
H.264 / MPEG-4 AVC
H.264 is also known as MEPG-4 AVC. H.264 uses the latest innovations in video compression
technology to provide consistently crisp and clear video for the best possible viewing.
Pros
H.264 delivers incredible video quality at data rates one-fourth to one-half the size of
previous video formats
H.264 offers dramatically lower bit rates and better picture quality than MPEG-2, MPEG-4
or H.263+
It is 2X times more efficient than MPEG-4. and file size is 3X times smaller than
comparable MPEG-2 Codecs
It is easy to integrate and covers wide range of picture format. Hence used in large
application segment.
Cons
H.264 requires longer encoding time
It is certainly not constricted and low-bandwidth friendly
More Hardware overhead is also one of the limiting factor
Licensing agreements are complicated.
MPEG-4
MPEG-4 is a standard currently under development for the delivery of interactive multimedia
across networks. As such, it is more than a single codec, and will include specifications for audio,
video, and interactivity.
The video component of MPEG-4 is very similar to H.263. It is optimized for delivery of video at
Internet data rates. One implementation of MPEG-4 video is included in Microsoft‟s NetShow.
Pros
Good image quality at low data rates
6. Cons
Standard is still being designed
DiVx
DivX is a brand name of products created by Divx Inc. The DivX codec uses lossy MPEG-4 Part 2
compression and it isfully MPEG-4-Advanced Simple Profile compliant; MPEG-4 ASP.
Pros
The Divx codec is quite simple to set up and use
It is popular due to its ability to compress lengthy video segments into small sizes while
maintaining relatively high visual quality.
Cons
It‟s a commercial codec, so in order to get all the options you have to pay money for it.
x264
x264 is a freely available open source implementation of the h.264 standard. H.264, or AVC as it
is sometimes known is a very advanced compression method that is part of the MPEG-4
standard.
Pros
It offers the best quality at the smallest filesize
Cons
x264 (or any h.264 codec for that matter) is that it can take bit of CPU power to play
Real Video
Real Media currently has only two video codecs: Real Video (Standard) and Real Video (Fractal).
Please bear in mind that this page only compares the one to the other.
Pros
RealVideo (Standard) is usually best for data rates below 3 KBps.
It works better with relatively static material than it does with higher action content.
It usually encodes faster.
Cons
RealVideo (Standard) is significantly more CPU intensive than the RealVideo (Fractal)
codec.
It usually requires a very fast PowerMac or Pentium for optimal playback.
Sorenson
The Sorenson Video Codec produces excellent Web video suitable for playback on any Pentium
or PowerMac. It also delivers outstanding quality CD-ROM video at a fraction of traditional data
rates.
Pros
Provides much higher image quality than Cinepak, with smaller files. It is often possible to
get twice the image quality at less than half the data rate.
Tuned to work well from 2 - 100 KBps.
Supports Media Cleaner Pro‟s variable bitrate encoding, which provides the best possible
results at any data rate.
Cons
Playback of CD-ROM video requires faster computers than Cinepak
Movies larger than 320×240, or at data rates above 100 KBps, do not play smoothly
except on high-end machines (such as a Macintosh G3). While picture quality is usually
7. outstanding at higher rates, you should test these movies on your target machines to
determine if playback performance is acceptable.
MPEG-1
MPEG-1 provides excellent image quality at CD-ROM data rates. One of the most popular uses of
MPEG-1 is the VCD, or “white book” video CD. MPEG includes both audio and video compression.
The biggest problem with MPEG is that it has high requirements for playback. Either a dedicated
MPEG decoder card must be installed, or a high-end CPU is required for software-only playback.
Because of this limitation, MPEG-1 has not gained wide acceptance in consumer titles.
Pros
Excellent image quality
Cons
Very high playback requirements
Majority of installed base not capable of viewing MPEG
Licensing fees (typically US $0.04 - $0.40 per unit) are required to distribute MPEG-2
video. There may also be fees for MPEG-1; there is some uncertainty regarding this.
Not well-suited to WWW video (the upcoming MPEG-4 standard will address this)
MPEG-2
MPEG-2 is a standard for broadcast-quality digitally encoded video. It offers outstanding image
quality and resolution. MPEG-2 is the primary video standard for DVD-Video
Pros
Excellent image quality
Cons
Very few people are currently capable of viewing MPEG-2
Licensing fees (typically US $0.04 - $0.40 per unit) are required to distribute MPEG-2
video.
H.261
H.261 is a standard video-conferencing codec. As such, it is optimized for low data rates and
relatively low motion.
Pros
H.261 is optimized for low data rates.
H.261 has a strong temporal compression component, and works best on movies in which
there is little change between frames.
Cons
Not generally as good quality as H.263.
It may not play well on lower-end machines.
H.263
H.263 is a standard video-conferencing codec. As such, it is optimized for low data rates and
relatively low motion.H.263 is an advancement of the H.261 standard; mainly it was used as a
starting point for the development of MPEG (which is optimized for higher data rates.)
Pros
H.263 is optimized for low data rates.
Generally better quality than H.261
H.263 has a strong temporal compression component, and works best on movies in which
there is little change between frames.
Cons
H.263 is CPU intensive
It may not play well on lower-end machines.
8. Understanding various Audio Codecs:
The audio codecs is a method of compression/decompression of audio file, audio data or
streaming audio format. The codecs stands for Coders / Decoders.
There are various kinds of audio codecs available. Since these codecs have been implemented by
different algorithms by number of companies; they have different specification and application in
various fields. These audio codecs generally complies Industry standards.
The various software audio codecs are:
AAC
AAC+ / AAC+ Enhanced
AC3 or Digital Dolby
Digital Dolby Plus
Speex
FLAC
MIDI
MP3
MP3 Pro
Monkey’s audio
OggVorbis
QCELP
Real Audio
WMA
Melody
HVAC
These various Audio codecs are technically differentiated from each other based on various
factors which includes compression technology / algorithm, platform supported, sampling, OS
supported etc
One can easily compare the various audio codecs on wikipedia.But still there is confusion which
codec is the appropriate? However it also depends on application. But understanding pros & cons
of some of these codecs gives us the better information and insight depth.
AAC
Pros
An international standard approved by the ISO
Flexible: supports several sampling rates (8000-96000 Hz), bit depths, and multichannel
(up to 48 channels)
Several implementations, including free and high quality ones.
Reaches transparency in most samples and for most users at around 150 kbps
Part of MPEG-4 specs
Anyone can create its own implementation (specifications and demo sources available)
9. Cons
Problem cases that trip out all transform codecs
Heavily patented
Increased complexity
AAC comes in different “flavors” (object types: AAC LC, AAC HE, AAC PS etc.).
Many (especially portable) players only support LC (at the moment) so you can have files
that are valid but your player won‟t play them.
AAC+ / Enhanced AAC
AACplus (AAC+) is a variant of AAC which is optimized for low bit rates developed by
Coding Technologies. It uses techniques including SBR (Spectral Band Replication) and PS
(Parametric Stereo).
Multi-channel support for 5.1, 7.1 and beyond (48 channels total)
Optimized speech, mixed speech/music down to 8 kbps mono
AC3 / Digital Dolby / Digital Dolby plus
Pros
Digital Dolby or AC3 decoder is the industry standard for DTV and DVD media. Nearly all
new DVD movies come with a DD soundtrack program
AC-3 provides only full range channels, its sound is really much better in terms of quality.
And it is also backward compatible.
Digital Dolby plus also supports 7.1 channel
Cons
Max support for 5.1 channel audio CDs, limited to 448 kbps maximum for Digital Dolby
SPEEX
Pros
Speex is an Open Source/Free Software patent-free audio compression format
Speex is based on CELP and is designed to compress voice at bitrates ranging from 2 to
44 kbps
Speex has a number of features that aren‟t in other codecs such as Intensity stereo
encoding, integration of multiple sampling rates in the same bitstream, and a VBR mode
Cons:
Speex is mainly designed for only three different sampling rates: 8 kHz, 16 KHz & 32 KHz
FLAC
Pros
FLAC is portable to many systems
Open source and freely licensed
The encoding of audio data incurs no loss of information.
Hardware support & Streaming support
10. Extremely fast decoding
Supports multi-channel and high resolution streams
Supports Replay Gain & cue-sheet (with some limitations)
Gaining wide use as successor to Shorten
Cons:
Compresses less efficiently than other popular modern compressors (Monkey‟s Audio,
OptimFROG)
Higher compression modes slow, for little gain over the default setting.
MP3
Pros
Widespread acceptance, support in nearly all hardware audio players and devices
An ISO standard, part of MPEG specs
Fast decoding, lower complexity than AAC or Vorbis
Anyone can create their own implementation (Specs and demo sources available)
Relaxed licensing schedule
Cons
Lower performance/efficiency than modern codecs.
Problem cases that trip out all transform codecs.
Sometimes, maximum bitrate (320kbps) isn‟t enough.
No multichannel implementations.
Unusable for high definition audio (sampling rates higher than 48kHz).
OGG VORBIS
Pros
(Ogg) Vorbis specification is in the public domain; it is free for commercial or
noncommercial use, under both (LGPL and BSD license)
Easy to use high-level API (Application Programming Interface)
Good all-round performance (>48 kbps – a leading codec at 128 kbps)
Well written specs
Supported by most portable (Ogg) DAPs
Suitable for internet-streaming (via Icecast and other methods)
Fully gapless playback
High potential for further tuning
Structured to allow the design for a hybrid filterbank
Cons
Limited official development (third-party developement is always encouraged)
Current implementations are more computationally intensive to decode than MP3