Codecs Revisited...

I had promised that I will revisit codecs soon... Here's a mish-mash of what I learnt about codecs (and other related concepts), this weekend.

CODECS
Compresser - Decompressor.
An application can use the codec installed in the OS (visible under the Control Panel > Multimedia > Devices section), the codec built as a default plugin into the application OR the codec available for download as a separate plugin.

Quality Ranking of some popular Audio codecs -
1. MP3 (LOSSY, NOT SO GOOD)
Tools used:
Use LAME mp3 encoder to create MP3.
Can also use Windows Media Player Version (WMP) 10 (the version 9, did not support encoding to MP3).
2. AAC, OGG (LOSSY, BETTER)
Tools used:
Use OggdropXPdv to create OGG vorbis.
Use iTunes to create AAC.
3. WMA (LOSSLESS, MUCH BETTER)
Tools used:
Use WMP.
4. WAV (BEST)
The 'Swiss Army Knife' of conversion software -
dbpowerAMP.


CONTAINER FORMATS
File formats used to store the video stream and audio stream created by a video codec and an audio codec respectively (might also be used to store only the audio stream along with the meta data). It also contains data to synchronize video and audio playback. That is how it differs from simple file archiving formats like zip files.
e.g. -
Containers exclusive to Audio -
WAV

Video and Audio supporting containers -
AVI - The popular container format used by Microsoft. Supported by Windows Media Player. Is the format used with DivX movies (at least the ones based on the DivX codecs upto 5.2)
MOV - Container format for files playable by QuickTime.
OGG
DivX

Ref URL -
http://www.matroska.org/technical/guides/faq/
http://en.wikipedia.org/wiki/Container_format



LAME
Stands for 'Lame Ain't an Mp3 Encoder'. The reason it was named as such was cause it was not designed to be a MP3 encoder initially. There are two versions of it -
(a) A command line utility - LAME Mp3 encoder. Might have a GUI front end to it e.g. - LameFE or RazorLAME. Also used with an output plugin for Winamp, named, out_lame.
(b) LAME ACM codec - The ACM codec version of the LAME encoder. Is installed as an audio codec in Windows and can be used, for example, with programs like FlaskMPEG to create DivX video based AVIs.

Using LAME -
Command line utility -
Can use some wonderful presets to forget learning all the different switches available in the command line utility.
ArsTechnia recommends -
--alt-preset standard. Is a VBR preset that uses an approximate bit rate of 190 Kbps AND bit rate fluctuation between 180-220 Kbps.
Using RazorLAME -
http://arstechnica.com/guides/tweaks/encoding.ars/5
Using Out_lame plugin -
http://www.free-codecs.com/download/out_lame.htm

Some other MP3 encoders -
Radium MP3 encoder, Fraunhofer encoder.

Ref URL -
http://www.free-codecs.com/download/Lame_Encoder.htm]
http://www.snipurl.com/ianq



DivX
A video codec. Esp. used to encode DVD MPEG2 files to MPEG4. Primary objective - compression.

Can download the latest version of the codec -
For Windows 2K and XP - Version 6.0
DivX Play bundle:
A codec + player version - Just to play DivX movies available on the Internet
DivX create bundle:
Codec + Encoder + Player (has a TRIAL version which canNOT convert DVD MPEG2 files without installing a PAID plugin)

For Windows 98, ME - Version 5.2
http://www.divx-digest.com/software/divxcodec5.html
Download the DivX Pro, Windows 98 and ME trial version from this page.

DivX Players:
Windows Media Player can also play DivX AVI files, if the proper codec is installed.

Configuring the DivX 5.2 codec for best results -
http://www.divx-digest.com/articles/divx52_setup.html
http://www.magicdvdripper.com/improve-divx-quality.htm

Other video codecs available -
xVid, Windows Media Video



How to uninstall a codec in Windows?
Do it from Control Panel > Multimedia > Devices > Audio / Video codec
Double click on the app codec and click on Remove. That is how I uninstalled LAME ACM codec after it began crashing my FlaskMPEG program.



How to uninstall a Winamp Plugin?
http://forums.winamp.com/showthread.php?threadid=26610



How to convert DVDs to DivX?
Use FlaskMPEG -
http://www.digital-digest.com/dvd/articles/dvdtodivx.html
Use MagicDVDripper -
http://www.magicdvdripper.com/

The common steps in the DVD to DivX conversion process (irrespective of the tools used) -
(a) Ripping the DVD (transfer the contents of the DVD - the video_ts folder) to the HDD, while removing the CSS encryption built into the DVD. The CSS encryption prevents the DVD's video_ts folder from being copied directly to the HDD. Can use tools like - MagicDVDRipper OR DVD Decrypter to rip.
Ref URL -
http://www.riphelp.com/articles/dvdripping_2.html

(b) Setting the conversion player options (e.g. - FlaskMPEG)

(c) Selecting the video codec and configuring it for optimum settings.

(d) Selecting the audio codec and setting its optimals.

(e) Actual conversion (One Pass or MultiPass, the latter results in a better quality file). Takes almost 8-10 hrs.

(f) Post conversion tweaks.



About CBR, VBR and ABR
CBR - Bit Rate stays constant once selected.
VBR - Bit Rate keeps changing depending on the amount of data to be encoded. Results in a smaller and a better sounding file.
ABR - VBR but the bit rate fluctuates around an average value.
Quality ranking -
VBR > ABR > CBR.
Ref URL -
http://arstechnica.com/guides/tweaks/encoding.ars/1