Wednesday, November 08, 2006

video codecs for submission to scientific journals

From time to time, there is problem with the choice of video codec for the submission to journals. "Information for Authors" normaly does not specify codec. Then the problem is poppualarity: DIVX or XVID are the codecs people install to their own computer to watch movies but not all scientists install extra codecs, simply because of the lack of knowledge or laziness. Then the problem is, although you submit movies as the supplementary material, reviewer might not be able to open the movie and the reviewer simply give up watching it.

For this reason, I looked around a bit to find out the most popualr codec. This does not mean a codex that is used widely. My goal is to find out common codec used both in Windows XP and MacOSX

In windows, there is a list of codecs installed by default.
Video codecs in Windows XP SP2
Codec Company
Cinepak Radius (Supermac/Compression Technologies Inc.)
DV Microsoft
Indeo Video 3.2 Intel
Indeo Video 4.5 Intel
Indeo Video 5.10 Intel
Indeo iYUV R2 Intel
RAW YVU9 Video Driver Intel
MJPEG Microsoft
MPEG-1 Video Decoder Microsoft
Microsoft ISO MPEG-4 V1 Decoder Microsoft
Microsoft ISO MPEG-4 V1.1 Decoder Microsoft
Microsoft CRAM Microsoft
Microsoft MPEG-4 (V1) Microsoft
Microsoft MPEG-4 (V2) Microsoft
Microsoft MPEG-4 (V3) Microsoft
Microsoft RLE Microsoft
Windows Media Screen (V7) Microsoft
Windows Media Screen (V9) Microsoft
Windows Media Video Standard (V7) Microsoft
Windows Media Video Standard (V8) Microsoft
Windows Media Video Standard (V9) Microsoft
Windows Media Video V9 Image Microsoft

In Quicktime7, following codecs are installed.
Supported Video Formats

* Animation
* Apple BMP
* Apple Pixlet (Mac OS X v10.3 only)
* Apple Video
* Cinepak
* Component video
* DV and DVC Pro NTSC
* Graphics
* H.261
* H.263
* H.264
* JPEG 2000
* Microsoft OLE (decode only)
* Microsoft Video 1 (decode only)
* Motion JPEG A
* Motion JPEG B
* MPEG-4 (Part 2)
* Photo JPEG
* Planar RGB
* Sorenson Video 2
* Sorenson Video 3

also in the PDF in Apple website (contains also audio codecs),

Ubucide text
CCIR 601
IEEE 1394
3G timed text

Comparing the list. I conclude that the best codec for submission is Cinepak or MPEG-1. These are pretty old and unefficient, but sufficient. One could also find that MPEG-4 is in both Windows and Mac, but the "Windows MPEG-4" is actually not MPEG-4.

Note: One weird thing is that Microsoft's MPEG-4 is NOT actually MPEG-4! The codecs were developed before the MPEG-4 standard was agreed upon, and Microsoft assumed that the MPEG-4 that they developed would be become the standard MPEG-4. Well, it didn't, which is the main reason why the codec's name was changed to Windows Media in later versions.

What does this mean to you? Right now, pretty much nothing, since there are very, very few applications that use standardized MPEG-4 at this time. For download and web distribution, it doesn't matter if the codec is MPEG-4 compliant or not. However, in the rare occasion that you are compressed a video for something that requires compliant MPEG-4 video, do NOT use Microsoft's "MPEG-4" codecs.

additional information for the codecs Cinepac and MPEG-1 part2.

(1) Cinepak

Cinepak was at one time the standard for distribution of video via CD-ROM. It was so successful that virtually every Windows or Mac machine comes with Cinepak preinstalled, giving it near-universal compatibility. However, while the compatibility is great, Cinepak's compression technology is terribly obsolete. Good-looking video can be had using Cinepak, but only with resulting file sizes that are many times larger than newer delivery codecs. Cinepak only offers a quality slider for control and often takes a long time to encode, although the resultant file does not take much computer resources to play back, so it may be a possibility if you need your video to be played on older machines.

(2) Cinepak
This was the dominant codec for many years, which lead to it being installed on almost every computer and giving it excellent compatibility, but from a technological viewpoint it is obsolete. MPEG-1 has replaced Cinepak as the new standard for universal playback. See the Cinepak entry in the AVI section for more information.
from Quicktime codecs

(1) MPEG-1 Part 2:

When it comes to compatibility, VCD has the highest compatibility of any digital video/audio system. Almost every computer in the world can play this codec, and very few DVD players do not support it. get a fully compliant VCD file, bitrates higher than 1150 kbit/s and resolutions higher than 352 x 288 should not be used (includes the *.mp3 standard).

wikipedia: video codecs

(2) MPEG-1 video was originally designed with a goal of achieving acceptable video quality at 1.5M bit/second data rates and 352x240 resolution. While MPEG-1 applications are often low resolution and low bitrate, the standard allows any resolution less than 4095x4095. Nevertheless, most implementations were designed with the Constrained Parameter Bitstream specification in mind.
At present MPEG-1 is the most compatible format in the MPEG family; it is playable in almost all computers and VCD/DVD players.
One big disadvantage of MPEG-1 video is that it supports only progressive pictures. This deficiency helped prompt development of the more advanced MPEG-2.
from AllExperts