B-T Group

We have a great affinity for audio as we evolved our way from radio, into professional audio, video and then web video including live streaming and library control systems.

Paul Yurt started in radio. As his career evolved he wanted to be more involved in the creative side of production and moved to professional audio. His professional audio experiences include Neve and SSL (Solid State Logic) as manufacturers. Hit Factory, Sterling Sound, MasterDisk and Sony Records (formally CBS Records).

We here at Broadband Tech Group are often asked to advise on, or actually encode large quantities of video, and audio materials for a variety of purposes. Now that web video has become common we are being asked to re-encode video which was previously compressed for some other purpose such as DVD video and the like.

Be careful; garbage-in usually results in garbage-out, when discussing quality video and audio.

What can be done to ensure higher quality video and audio, when encoding video from tape or disk?

The question is complex - there are many areas and issues related to "quality". We will not attempt to answer the question of quality in one posting, of this forum but rather, in a series of postings over time.

First let's look at the issues which are a part of "quality". Quality is partly determined by the type and grade of the source material(s). Souce materials can be broken down to include

a) media format

b) recording device quality

c) micing and lighting techniques

d) transfer issues etc.

There are some general rules of thumb which can be applied to video and audio quality including

1) high quality recordings will generate in higher quality results

2) late stage encoding is better

3) employ high quality codecs

4) determin and follow best practice techniques for multiple format conversions

5) eliminate compression before encoding whenever possible

6) cause minimal transcoding or encoding of encoded materials.

In the Linux world, a distro is the short name for a "distribition of Linux".

Distributions are packages of software. When you buy software such as Windows the package includes the operating system and at least a web browser, text editor, calculator, file manager, etc. Then to make windows useful you typically need to install other software such as a “real� word processor, a spreadsheet program, accounting software etc.

Since Linux is free (open source), things are a bit different. When Linux is distributed it comes with a large collection of software packages. Most software the packages in a distro is tested to work with the distro and thus it is called a distro or distribution.

There are very many open source “packages� (bundles of software) capable of running under Linux. Many of the packages (softwares) included in a distro(bution) are tested to work with the distro.

When you install software packages in Linux, often there are “dependencies�, other software required to make the packages work.

In a distro the packages and the dependencies are tested to work together and when a package is installed the “package manager� checks to see what the dependencies are. If a dependency is found the package manager looks to see if this package is installed, and if not suggests it be installed with the package you are trying to install.

There, that's the story on “what is a distro�. In summary, a distro is a bundle of 1) an Operating System and 2) a collection of tested packages with 3) a way to manage the dependencies.

There are distros with names including: Redhat, Suse, Ubuntu, PCLinuxOS, openSUSE, Fedora, SimplyMEPIS, Debian, Sabayon, Mandriva, Linux Mint, Yoper, Knoppix

Teams of people, typically volunteers, make sure all the software in a distro is likely to operate. When someone installs from a distro they use a CD, DVD, or network, from which to install. Initially when installing the installing user needs to indicate 1) where to install the new software 2) how to boot once it is installed and 3) what packages (applications) to include in the install.

Many distros are generic, and include many more packages than needed, for whatever a user is likely to want. Thus a required element of installing from a distro is specifying the packages to include in the install.

There are some distros specific to a task, such as video editing, monitoring a network, portable computing etc. Specialized distros are collected to help users achieve a specific task without running around and finding all the parts needed to perform the task.

You can access detailed information about distros by going to the website for each distribution or from distrowatch.com

-----Paul

Here is a list of the most popular distro in page rank order on June 25 2007: 1 Ubuntu 2 PCLinuxOS 3 openSUSE 4 Fedora 5 MEPIS 6 Debian 7 Sabayon 8 Mandriva 9 Mint 10 Damn Small 11 KNOPPIX 12 Gentoo 13 Zenwalk 14 Slackware 15 CentOS 16 Kubuntu 17 Dreamlinux 18 Vector 19 Puppy 20 FreeBSD

Again: A "Distro" is a release of a collection of Linux software.

Many times the packages work together, but not always. Because there are thousands of packages in most distros, it is not possible for all of the packages to be tested for working together. So package conflicts do occur and can be reported to the distro team.

We put up several versions of the AWS 900 video for Solid State Logic this weekend. The source of the videos is a single DVD. They are of mixed desitnation resolution, and quality.

In these video Ryan Hewitt an audio mixing professional (Blink-182, Red Hot Chili Peppers, Pepper, Mutant Teenage Ninja Turtles Original Soundtrack) explores and explains the AWS900 audio mixing workstation.

Ryan details the analog and digital sides of the mixer, exploring the channel strip, faders, aux and cue sends, effects, interfaces to the DAW and other details of this advanced workstation/mixer from Solid State Logic (SSL).

The video originated on DVD. There are pre-encoding aliasing artifactson the sources, resulting in slur at  high motion moments, mostly in the begining of the segments. It would be nice to encode these segments off the original master.

  If you take the time to look at the video we would welcome comments.

Paul

Yahoo Higher Res

Yahoo Lower Res

YouTube

Watchdogs of the world.

The practice and behavior of industry and domestic governence to trace and track individual is a missleading story.

On the surface consumers are told thier privacy is "protected" by laws and practices, but if you look carefully the processes called protections are carefully crafted and designed around a structure which provides room for sharing of all sorts. There are practices which allow individuals to be traced using mutiple technologies. It is especially practical to use multiple technologies for tracking and tracing.

Recently some long time snooping practices were revealed. The best presentaion of this was in a segment of Nightline where Mark Klein a former At&T Technician did the heroic deed of describing the NSA collecting process within telco switching offices.

Here are some links http://www.eff.org/legal/cases/att/ http://www.eff.org/legal/cases/att/news.php

I think it's probably good that our government keep a watch on things. What I think is wrong is the fact that the governemnt lie about what it does. I always believe lying is not a good thing.

mplayer it is not distrubuted with fonts for subtitles. You can assign almost any font to be the font source for your subtitles. Assigning involves either copying a font to the mplayer home directory, or making a symbolic link to a font, contained elsewhere on the system, for the font of choice. Here are some details:

The subfont.ttf issue with mplayer.

One solution to the missing font issue is to make a symbolic link named "subfont.ttf" and pointing it to an installed ttf (TrueType) font globally in /usr/local/share/mplayer (as root)

For example, using the times font :

You can move to the mplayer folder with:

cd /usr/local/share/mplayer

Then make the symbolic link with

ln -s /usr/share/X11/fonts/TTF/times.ttf ./subfont.ttf

If you are not sure where the .ttf files are on your system try to "find" them using

find /usr/ -name *.ttf

(Using fedora 6) :

cd $HOME/.mplayer (or whatever your mplayer root is)

ln -s /usr/X11R6/lib/X11/fonts/drakfont/ttf/times.ttf ./subfont.ttf

(Using fedora 7) :

cd /usr/local/share/mplayer (or wherever your mplayer root folder is)

ln -s /usr/local/X11/fonts/TTF/luxirr.ttf ./subfont.ttf

You can also set a path to a font.desc file:

-font Search for the OSD/SUB fonts in an alternative directory (default for normal fonts: ~/.mplayer/font/font.desc, default for FreeType fonts: ~/.mplayer/subfont.ttf). NOTE: With FreeType, this option determines the path to the text font file. With fontconfig, this option determines the font- config font name.

EXAMPLE: -font ~/.mplayer/arial-14/font.desc -font ~/.mplayer/arialuni.ttf -font ’Bitstream Vera Sans’ Look in man mplayer for more info:

I hope this is helpful.

Paul

This is a flash video test from the b-tg.com site The link activates a video encoded for Solid State Logic which details thier AWS900 product.

Solid State Logic AWS 900

Paul's Notes:
I notice if the buffer get underrun you will see a spinning flash logo. In my experience when it was paused briefly it played smooth after that.

Paul Yurt paul@b-tg.com

FLASH HOSTED ON (b-tg) video server1

Click To Play Flash 320x240

Tell me what you see.