Codecs, encoder,decoder, Directshow, DirectX etc. etc. ...(blink blink
blink).....My problem is that I really don't have an understanding of what
role these and other elements play in the whole process, which makes it more
difficult to ask intelligent questions since I'm surely using terms
incorrectly.

Can someone offer or point to a good link that gives a flowchart type
explanation of what exactly happens during capture/viewing/editing of video
from a digital camcorder? Both in the case of using the camera strictly as a
pass-through or making tape on the cam and then going to the h/d as digital
video (or even mjpeg for that matter.)

The signal or image goes into the camcorder and...what happens to it? Then
goes out to the Firewire port or capture card and....then what?  And what
happens when you view it? Or send it back to a digital or analog
camcorder...

I'm frustrated that I'm drowning in a lack of understanding.

In fact, that's another thing. Is all non-streaming video either digital or
mjpeg or are there other categories as well? For example are mpeg-4, divx,
etc. altogether different animals?

My sincere appreciation for all shared wisdom.

Doc

    Graphedit is a tool to combine filters graphically to test and create
DirectX objects.

    May I suggest the

    microsoft.public.platformsdk.directx


    or

    microsoft.public.win32.programmer.directx.xxxxxx

    where xxxxxx is audio, graphics, sdk.. etc..

    There is a lot of discussion going on about the inner workings of
directx.


Show quoteHide quote

codec stands for encoder/decoder.   The codec used is specified in the
file by a fourcc code uniquely identifies the codec.   Examples of
these are XVID, DIVX etc.

My understanding is that if the application uses DIRECTSHOW  to display
the video you start talking about filters rather than codecs.

When putting video to DVD , VCD etc there are standards that define the
type of video files required. 

www.videohelp.com is a good source.

I guess I'm looking for something that essentially spells the basic process
out more concisely than trying to put it together piecemeal. I.e., if I go
to this group, I'd still be in the same boat I'm in now.

Doc,

    DirectX is simply Windows' response to those of us who were developing
for the PC and early Windows versions. Back then we were ablke to write
directly to hardware buffers on video cards and as Windows grew up that
functionality disappeared. So DirectX is a solution that provides faster
drawing, image processing and audio processing.

    It is a fairly steep learning curve to get it all sorted out.

    Filters and codecs are not related per se. The DV filters are processes
that perform some action on the data stream. Or they 'render' that stream to
a device. If you are a programmer you should download the DXSDK from MS and
start reading the materials and running the sample apps that come with it.
Then you can begin asking questions in the development newsgroups. Even if
you are not a programmer the SDK can be very helpful.

There are also a ton of books out on DX.

best


Show quoteHide quote

Show quote Hide quote   Try; www.doom9.orgwww.digitalfaq.comwww.digital-digest.com

Luck;
    Ken

Doc wrote:
Show quoteHide quoteDigging deeply into the specifics of exactly what happens to the data
each step of the way is a good side hobby, but I get the feeling that
your drowning in trees, so to speak.

You take your generic batch of video. Typically, when it flows down the
firewire line to your computer (The technical term for this process is
'magic') it ends up in a format called DV25. (On your basic Windows
computer) This has some compression on it, but seems to be an industry
standard that balances size with editing potential.

You take your editing progam, snip snip, paste paste. Then, you want to
put it all together in a way that others can view it. You render it into
another format using an encoder (which may or may not be part of your
editing program) and the encoder has a choice of codec. The codecs are
what till put your video into one of a whole bunch of different formats.
Divx, Xvid, Mpg 1 and or 2, Avi, Windows media, Quicktime, and on and on
and on.

As said on this forum many times, the file type is just a 'wrapper'. In
other words Avi dosen't necessarily mean anything specific as you can
have uncompressed avi's, ntscdv avi's, Divx avi's, xvid avi's and I'm
sure there are more flavors.

But what about DVD's? Well, DVD's are really just MPG2 files. But
nooooo, they couldn't just leave them that way could they? No, they are
all broken down into VOB files. Again, more 'standards'. And, I'm sure
there is a long long detailed history and explanation as to why the are
put together this way, but, do you really need to know this to create
DVD? No. Still, its fun to look it up in your spare time.

Divx is an implementation of MPEG-4, as is Xvid.

Basically you have two major categories of digital video compression, DV
(which includes DV25, DV50, DVCAM, DVCPRO, and all other 'Intraframe-only'
codecs; and you have MPEG based interframe codecs known as MPEG-1, -2, and
-4 as well as MJPEG and a few others like HDV.

Intraframe means that each frame is compressed individually and exists as a
complete frame. This is best for editing, as you can cut anywhere and
there's nothing to worry about.

Interframe means that most frames are encoded as 'the difference from the
last frame' to save space - but you lost editability as any cuts have to
either fall on the "I frames" which are intra-only frames, or you have to do
some magic to make a new I frame from a non-I frame.

Almost all consumer digital video camcorders use MiniDV, which is known as
DV25 for its bitrate of 25Mb/s - the other systems out there would be using
MicroMV (MPEG-2 on a tiny tape), HDV (MPEG-2 on a DV tape), or DVD-RAM
(again, MPEG-2).

Capturing DV25 video from a camcorder is lossless, as the 'encoding' upon
capture is really just ensuring that there aren't frames dropped in the
stream being written to the hard drive. Outputting the edited DV (assuming
there's no effects or transitions applied) is also lossless, as you're just
streaming pure DV25 back onto the tape.

To RS: DVD-Video uses program stream VOBs so that you can have multiple
synchronised audio and video tracks in one file without using native
timecode - it just multiplexes every track into a Video OBject file so the
decoder can just pull out whichever tracks it wants. See, not that long or
difficult an explanation :)

On Sat, 06 Aug 2005 02:14:14 +1000, Cail Young <nospam@anywhere.com> wrote:

You left out the DV25 derivative, Digital-8.

cheers

-martin-

Martin Heffels wrote:
Show quoteHide quotequote: CDs play backwards in the Southern Hemisphere due to the
Coriolis Effect

I thought that was the explanation for the different frame rates for
PAL and NTSC.

Doc wrote:

Not a flowchart, but a complete set of definitions covering compression,
codex, etc.

http://www.microsoft.com/mspress/books/sampchap/6428.asp#126

While I'm still not providing you with the flowchart you asked for (not a
lot of time on my hands right now), here are a couple more resources for
you.  It sounds like you are very new to digital video (forgive me if
I've come to the wrong conclusion).  The attachments here will explain a
number of concepts that may help you build that flowchart in your head
until someone else here can give you one.  Some of the other links
already posted are indeed worth a look.  Make sure you don't pass those
up.

Yes, the pdf files provided are from Adobe and Avid, and so may speak
specifically about their products, but there is a good amount of
foundation in these 3 files.

The DV Primer may be the best starting place.  It talks you through from
shooting video to capturing and editing, to making DVDs.

The Intro to DV is more selling tool than anything else, but I included
it anyway. 

The Glossary from Avid is a good resource to look up those terms often
tossed around by some of the more experienced in the community

Hope you find some help in these files.  You should let us know what
resources you actually get some usage out of so that when other new users
ask the same questions, there is some idea of what really helps and what
doesn't.

Erich

Show quoteHide quote

Show quote Hide quote OK, that was my first time trying to post a file and it doesn't appear to
have worked, so here are links to the files online.

http://www.avid.com/freedv/avideditingglossary.pdf
http://media.studio.adobe.com/linked_content/en/dvprimer/dvprimer.pdf
http://media.studio.adobe.com/linked_content/en/intro2dv/intro2dv.pdf

You may have to register at Adobe's site to get their 2 files.  The Avid
link shouldn't require any registration.

Good luck

Erich

Show quoteHide quote

"Erich" wrote ...
Posting attachments (particularly big attachments) to any
newsgroups that do not include the word "binaries" in its
name is an abuse of Usenet. None of these newsgroups
are binary.

Far worse than just not working, posting large attachments
to non-binary newsgroups jeopardizes the newsgroup's
propogation around the planet. If people start posting attachments
to non-binary newsgroups, some (many?) service providers
will just drop the newsgroup because of abuse. This is bad
for you and for all of us.

THAT is the correct way to provide the information.
Good for you.

On Sat, 6 Aug 2005 17:04:35 -0700, "Richard Crowley"
<rcrow***@xpr7t.net> wrote:

I thought news servers which cared about such things just noted the
lack of the binaries flag and dumped attachments.   I've heard reports
of a user's ISP complaining about uploading attachments to
non-binaries groups.  But not of the group being deleted.   Has it
happened?  What group?

Show quote Hide quote Anyone can host a list. Or a group or whatever. There is no possibility that
discussion groups will disappear because some are dumped from servers. If
you want to get into a discussion about digital video there are probaly no
less than 20,000 places to do so.

These newsgroups have become discussion areas for ultra low end software and
people who want to cut commercials out of their recordings of crappy cable
shows or whatever. That , to me, is the same as have the group dumped from
the server for abuse  but I can find plenty of places to get information if
I need it.

"Jona Vark"  wrote ...
You don't appear to understand how Usenet newsgroups
are created and propogated.  OTOH, if you are talking
about people creating their own web-based discussion
boards, that is a completely different thing.

You are right. They don't "disappear". There are 10s
of thousands of them out there that are completely
orphaned/abandoned because of poor/no circulation.

Then it is curious why you hang out here at all?

Of course I do. But there is no reason discussions have to be on usenet. I
maintain lists and boards while working with groups of engineers on
projects. Usenet is free and easy but by no means is it something we would
miss if we had to come up with alternative discussion methods.






Therefor usenet is not necessary. And alternatives are many. I wouldn't have
a problem if any of the groups I visit disappeared.


I hang out here just for your tidbits of wisdom, which are many.   ;p

Been here for so many years it's a habit now.. I started mucking with Video
NLEs  in 93 joining discussions on the net shortly thereafter. Don't recall
what year my first post here was. The Condit days for sure.

My point was about the current crop of discussion in this NG. It has changed
from editing to ripping. And it is far less appealing that in the past. So
for all practical purposes , it might as well have disappeared.

"Jona Vark" wrote ...
Speak for yourself. Usenet is far and away more fast
and easy than web-based discussion solution I have
seen yet. If you have some examples of methods that
beat Usenet, I'd be interested in seeing them.

Richard

    I always speak for myself. As you have here.

    While you believe this is fast and easy I believe it is crowded with
NOISE and has random direction. Only a small percentage of posts are
relevant topics often and the tenor and direction of newsgroups is like the
wind. Always changing.   I have no problem with more elaborate methods of
group communication. They do not frustrate me as much as they may frustrate
you. Although I fail to see why 'blogs' have caught the attention of so
many. Seems like painting potatoes red and selling them as apples.. They're
just lists dressed up to carry  ads.

    Your tone has become somewhat terse in the last few months. Especially
initial responses to newbie posters who may not understand what they are
doing yet. Although you usually post accurate intelligent responses I can't
believe you enjoy it that much here.

"Jona Vark" wrote ...
Usenet has always been like this. It doesn't bother me.
I scan the subject lines for things that look interesting
to me and make effective use of killfiles and ignore
flags. I don't find any of the things you complain about
to be particularly troublesome.

I am frustrated by the clunky user interfaces (frequently
not even threaded!)  But it isn't really because they are
"elaborate", but that they are so low volume that they
aren't terribly interesting, nor do they have good, vigorous
discussions.

I agree that blogs seem like PZM microphones, pet rocks,
and chia-pets. An unexplainable craze.

I will try to temper my handling of newbies.  But there are
some semi-regular people who come here every few
months with pretty hair-brained stuff. And people who
seem to want others to do their research for them. Perhaps
you haven't hung around here consistently enough to
recognize them?

Perhaps I should make more references to this...
http://www.catb.org/~esr/faqs/smart-questions.html
Or one of my favorite quotes: "I'll try being nicer if
you'll try being smarter."  :-)

I enjoy it quite a bit. I just have low tolerance for
foolishness.

some semi-regular people who come here every few
months with pretty hair-brained stuff.


I suppose that's whay I am losing interest in this NG and pretty much come
by out of habit. I read a lot of your responses.

http://www.catb.org/~esr/faqs/smart-questions.html
Or one of my favorite quotes: "I'll try being nicer if
you'll try being smarter."  :-)


That's an interesting site. I guess I can't assume they are asking stupid
questions for any other reason than they don't understand the subject
enough. If they did they wouldn't have to ask. I taught myself the skills I
use now to make a living. And I have a few folks who were patient when I
asked dumb questions to thank for help along the way.
Then again.. some people are just plain stupid.

You used to be more patient. But I am usually far less patient than you.

Just what do you mean by "film".


On Mon, 8 Aug 2005 22:54:33 -0700, "Richard Crowley"
<rcrow***@xpr7t.net> wrote:

Show quoteHide quote

"Donald Link"  wrote ...
Huh?  The word "film" doesn't appear in the thread.

"Laurence Payne" wrote ...
Few things in life are that simple. There are probably at
least a dozen different NNTP server apps and you can
bet that they likely don't all work alike.  Lots of NNTP
service operators "budget" a certain amount of disc space
for certain newsgroups, and those that consistently exceed
the capacity either get reduced in storage time or just get
dropped completely.

Usenet news is not a profit center for most ISPs and they
can't afford to have a high-priced expert spend a lot of time
fine-tuning the service.  You and I may read only a few
newsgroups, but there are something around 100,000 of them
out there and individual attention and tuning seems unlikely.

Usenet is littered with thousands of newsgroups that are
no longer used because providers dropped them for abuse
(attachments in a non-binaries group among the problems.)

Perhaps a better question is "where?"  Remember that the
entire system is voluntary and "best effort" and nothing is
guaranteed.  The more servers that drop a newsgroup
(independently, one at a time), the lower the volume
because of lack of circulation, and that just feeds on
itself until nobody carries it anymore.

This may not be exactly what you're looking for, but perhaps it's a start:

http://groups-beta.google.com/group/rec.video.desktop/browse_frm/thread/deaa1ef5d4c08de6/dd3d097620a96417?lnk=st&q=ptravel+video+authoring+capturing&rnum=2#dd3d097620a96417

http://groups-beta.google.com/group/rec.video.desktop/msg/48a62b4c98ad3589?dmode=source&hl=en

Simple.

Analog video (voltage signal; NTSC or PAL standard;
http://en.wikipedia.org/wiki/NTSC; keep in mind the different IRE setups
for Japan vs. USA etc. 0 IRE vs 7.5 IRE; IRE is an arbitrary unit for
gray level, which is really the amplitude of the voltage representing
the gray level. 100 IRE is pure white, while the video blanking level is
0 IRE. One IRE unit is 7.14 millivolts.) goes into DV converter box or
digital camcorder analog to digital passthrough port (voltage signal
gets converted by hardware chips into standard DV video feed;
http://en.wikipedia.org/wiki/DV), then is transfered over the standard
firewire/ieee1394/iLink cable and ports from the converted/camcorder to
the PC that has a firewire port (same thing, different names, some
copyrighted just to confuse consumers - standard universal name is
ieee1394; firewire is the name used by Apple initially; iLink is used by
Sony; http://en.wikipedia.org/wiki/Firewire) as a standard DV video feed
that gets dumped into an AVI file
(http://msdn.microsoft.com/library/default.asp?url=/library/en-us/directshow/htm/dvdataintheavifileformat.asp;
AVI is merely a wrapper/container; you can have different encoding
formats such as DV, MPEG, etc inside for video, along with different
audio encoding formats - raw, wav, ac3, mp3, etc.; the header of a AVI
file allows the computer to select which codec/decoding methods to use
to correctly playback the file) on the hard drive of your computer at
the standard DV video rate of 13GB/hour.

Editing an AVI file merely opens up that file, decodes the header, then
decodes each frame of the video as needed into RAW video format
(uncompressed) for manipulation by the video editing program.  After
edits are finished, the video can either be stored as a RAW video format
on the Hard drive in AVI format, or compressed and stored as a DV AVI,
MJPEG AVI, mpeg-1/2/4 MPG file, etc using the selected codecs
(compression algorithms stored inside a single file that can be run by
the computer to compress video/audio streams;
http://en.wikipedia.org/wiki/Codec).

Viewing is merely a subset of the above - merely the decoding part
followed by display of the image frame on the monitor.

---

Of course, if you really want the technical details of what's going on,
you can always look up the specifications for each part of the pathway
in detail.

"Doc" wrote ...
It would be extraordinarly helpful to know WHY you are asking.
Are you just curious about how your computer imports video from
your camcorder and edits it?  Are you trying to solve some problem?
Are you thinking about wringing some application software and/or
drivers/codecs?

IMHO, your question is too big and diverse to answer adequately
here.

"Richard Crowley" wrote ...
Bzzzzt! I meant "writing", but maybe "wringing" is a Freuian slip! :-)

Show quote Hide quote The immediate motivation is to solve a problem. But I find it's difficult to
navigate the tools that have been suggested such as Graphedit, due to a lack
of an overall understanding of the process.

"Doc"  wrote ...
Show quoteHide quoteDid you ask for help with the problem? How did you arrive
at the notion that Graphedit is the solution?  Seems dubious
that you can arrive at a solution by asking theoretical questions
about codecs?

??

This thread would in fact be part of the answer to that question. I've asked
several.

It's part of the input I've gotten in response to the various questions I've
asked here and in other places.  In essence I didn't arrive at the notion,
someone else suggested it.  If I knew enough to determine if it is or isn't
going to be useful, I imagine I wouldn't be having the problem.

Some part of the chain of events between the Firewire port on the camcorder
and my eyeballs when viewing the captured image is causing the banding
artifact that I've described at length. Ergo, it's logical that I gain an
understanding of that chain of events.

See the title of the thread. Re-read the initial post, in particular the
first paragraph. I'm trying to gain an understanding of the process. My
query isn't restricted to just codecs as such. Trying to see how it all fits
together.

"Doc" wrote ...
It would be helpful to keep the entire discussion together
to help people understand the whole picture.  Starting a
new thread, and especially one with no reference to the
underlying problem, just causes you to start over again
almost from scratch.

Did you ever post an image of the "banding" you are seeing?

http://groups-beta.google.com/group/rec.video.desktop/browse_frm/thread/436e26c783d75a22/78ad22d108aacb12?q=Should+mpeg+and+DV+video+look&rnum=1#78ad22d108aacb12

An entire thread devoted to it, my initial inquiry contains a link to a page
I put up.  If that link causes issues, the title of the thread is:

Should mjpeg and DV video look essentially the same on a tv? More vertical
banding problems.

Or here's the link to the webpage:

http://home.mpinet.net/~docsavage20/examples_of_video_banding/index.html

http://groups-beta.google.com/group/rec.video.desktop/browse_frm/thread/436e26c783d75a22/78ad22d108aacb12?q=Should+mpeg+and+DV+video+look&rnum=1#78ad22d108aacb12

As a note, don't read too much into the fact that the borders on the images
are different -  i.e. the ones from the DV video with the banding have black
borders put on with Virtual Dub, the mjpeg stills don't. Has no bearing on
the presence of the artifacting.

Show quote Hide quote Even I don't fully understand Graphedit... I can fiddle with it to make it
dump a WMV into a DV file, but aside from that it's quite confusing.
Basically what the program does is let you build an alternate filter chain
for any situation. If you 'render' a file within Graphedit it'll show you
the chain that a DirectShow application would use to display the video. You
can then modify the chain to your heart's content and if you include a
fileout or dump filter you can write the changed file to disk.

Show quote Hide quote   Which, if you were following Doc's posts and my replies from
the beginning, would explain why I suggested he use GraphEdit
to see what DirectShow was using and have a way to try some
alternatives.  Your description would suggest that you aren't that
confused, regarding GraphEdit; that is what it's for.  In fact you
seem to have found a use, well beyond it's normal intended
function.

Luck;
    Ken

My confusion is at a more specialised level, such as why certain filters
just won't connect... Overall I do 'get it', yeah.

Should mjpeg and DV video look essentially the same on a tv? More vertical banding problems.
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