Video Guides >
Encoding/Converting > Introduction
Video encoding is
one of those important steps in a video that will determine
whether the image output looks good or bad. The technical term for
this process is 'encoding' but is often referred to as
'conversion' or 'converting'. This guide will use both terms
interchangeably.
What is video encoding?
What is video conversion? Why do it?
Not all video is the same. Digital video can exist as
any number of formats, using any number of settings. When a
digital video file does not meet the specifications, or the
file type is bad for the intended use, it must be converted
to the proper format, using video encoder hardware or software.
What are Formats and Specifications?
The word "format" is used for many things in
video, but it tends to confuse people for this very
reason. So let's clarify some definitions real quick:
Video Format: This include filetypes, like
MPEG-1 (MPG), MPEG-2 (MPG), Quicktime (QT), RealMedia (RM,RMVB), Windows
Media (WMV), H.264 (MP4), Divx and Xvid (AVI), FlashVideo (FLV),
etc
Playback Format: This refers to the final product
used when viewing the video. Examples include DVD-Video (DVD), VideoCD
(VCD), streaming video (Youtube, Flash)
Video Specifications: For example, DVD-Video
specification uses MPEG-1 or
MPEG-2 with certain resolutions and settings only -- any old
MPEG-1 or MPEG-2 will not suffice. See the Understanding
Your Source capture guide for some more information on the various
digital specs for disc-based MPEG (VCD, DVD, etc).
When encoding video, you must consider (1) the
original source and capture methods, (2) any later encodes that
were performed, and (3) the intended output. Only by
analyzing those aspects, and then considering all the
options, can a high quality encode be performed. Converting
video properly is not simply a matter of pressing the "Go" button in an
encoder program.
Optimal
Encoding Solutions
What are the best methods
to encode video?
1. Avoidance. The first best method is to simply avoid it when possible. As was
mentioned in the Introduction
to Video Capturing guide, under some conditions there is nothing to gain by
capturing to an AVI and encoding to MPEG later on. If
you have an excellent capture card or DVD recorder that does
a quality MPEG capture, then you can often skip the
re-encoding step.
2. Start with quality source, to avoid re-encode
degradation. The second best method is to start out with high quality
uncompressed or low-compression formats -- not a low-grade
download from the Internet, be it Youtube or some other
method. Uncompressed captures are usually
done for one of 3 reasons:
(1) Because the capture hardware
is inferior,
(2) because the device is a DV camera or
limited to editing formats like MJPEG only, or
(3) because
the video needed extensive editing.
After capturing/recording, and any needed editing, encode
with settings appropriate for your project, be it a DVD, Blu-ray
disc or Youtube/streaming media.
What are the conversion
methods I should avoid?
Making bad video is really easy to do:
(1) Do not pay attention to the settings and open up the source
file.
(2) Use a wizard in some encoder software and just guess
at what you need. Or let the program take control and do it
for you, often equally incorrect as a human's blind guesses.
All-in-one tools are the worst. Again, converting
video is not simply a matter of pressing the "Go" button in an encoder!
Bad conversions will result in disappointing video
quality!
Analyzing
Sources
Not understanding
the source files when encoding will often result in bad
quality and playback problems. In order to encode an
MPEG (or anything for that matter) into a decent quality
video, you must understand the settings of the source file. Improperly
converting frame rates, aspect, interlace or resolutions
will result in a disaster.
There are two reasons a person will need to analyze the
source:
1. If you did not capture the source then analyze the
source.
2. If you captured it but did not pay attention to the
capture settings, then analyze the source.
I find that the best tool for this purpose is GSpot Codec
Information Appliance. See image below. Open the
video file using the "..." button towards the top
center of the screen. It will open the video and analyze it. You can render to see
more detailed information about how your system currently
reads the file, and if the proper codecs are installed on your system.
Software
Video
Encoders
Software is often
chosen by home users and hobbyists, but also by studios and
professionals at all levels. It takes time to encode with
software -- often many times longer than the video itself --
but results can be quite excellent, depending on the program
used. All encoders are NOT equal.
The following
chart shows a few of the more popular encoders available,
with information on suggested uses, quality and cost.
Before committing funds to any piece of software, consider
using trial versions if available.
| Encoder: |
Cost: |
Suggested use, more
info: |
Output
quality: |
| TMPGEnc
Encoder |
$35 |
MPEG
encodes, such as VCD or DVD. Suggested for pretty much
any kind of source file, and will open most source
files with codecs installed. Especially useful for the
many built-in video filters to restore video. Enormous
amount of encoding options. GUI and wizard-based
interface. |
Very
good output quality. Has tendency to have slight noise
in files, even with decent bitrates, but not overly
noticeable. Pretty faithful to the source. Fully
customizable. |
| MainConcept
Reference |
$450+
(or $Free Included in NLE) |
Encodes from high quality sources, or as an output
encode from editors like Adobe Premiere and Sony
Vegas. Easy GUI interface. Converts to many formats,
including MPEG-2, H.264/AVC and others. |
In
recent years, MainConcept has come to be one an
industry standard software encoder, known for its
excellent quality, surpassing competing
products. |
| VSO
ConvertXToDVD |
$50 |
Converts
many popular Internet format videos, such as AVI, XVID,
Divx, and MKV to DVD. Good hobby/consumer software. |
Quality
is very good, and the encoder is very fast. Support
1-pass or 2-pass encoding. |
| Grass
Valley Procoder |
$400 |
Professional
MPEG and streaming video. Only suggested for
self-captured high quality AVI files or DV camera
footage. Exists as standalone or as plugin for
NLE timeline output. GUI and wizard-based interface. |
Excellent
high quality, known as quality professional encoding
application. Fully customizable settings. MPEG output often
looks indistinguishable from the uncompressed source. |
| VirtualDub |
$Free |
AVI
codec encodes, such as HuffYUV format. Output options
depends entirely on the installed system codecs. GUI
interface. |
Depends
entirely on the settings and codecs being used, but
can achieve quite acceptable results in decent
quality. Fully customizable. |
| Cinemacraft
Encoder (CCE) |
$2,000 |
Only
able to encode MPEG from AVI source. Exists as
standalone or as plugin for NLE timeline output. GUI
interface. Very expensive for what you get. |
Very
good output quality. Tends to add mosquito noise to
the video a bit, so not overly faithful to the source.
Fully customizable. |
Beyond software titles,
there are some general comments that can be made about types
of encoding software that exists out there. The chart below
has a few examples:
Freeware:
BBMPEG, QuEnc,
HC Enc |
$Free |
Free encoders. Usually very limited in scope, only
able to open certain kinds of files. Not suggested.
Usually GUI interfaces, though some are command-line. |
Often
mediocre quality at best. Some of the better ones have
near-eternal encode times. Usually not worth the hassle, spend
$50 on a good encoder if available. |
All-In-One
tools:
Nero, Roxio, Toast |
$Free
to
$100 |
Never
suggested. Usually wizard-based interfaces. |
As
discussed above, all-in-one tools blindly encode
video, often giving dismal results. |
| Proprietary
tools: Quicktime, Real, Window Media Encoder |
$Free
to
$100 |
Only
suggested for proprietary encodes. Tools released
in-house by the format creators. Usually wizard-based
interfaces. |
Usually
quite decent, tools are dedicated to their formats. |
Hardware
Video
Encoders
As mentioned above,
software encoding takes time, often many times longer than
the video's running time. That's fine for casual projects or
even professional projects where it's been budgeted into the
calendar. But for many professionals and broadcasters,
that's not fast enough! Enter hardware encoders. We'll add more on this topic in the
future.
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