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RS
Guest
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 Posted:
Wed Nov 09, 2005 5:06 am Post subject:
Plain English explanation of direct show |
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Having dug on the web a bit, I basically only found out that Directshow
is the Mikeysoft sucessor to Active Movie. Other than that, there really
is not alot of explanation that does not get into deep geek.
So, could someone explain what direct show is? When and why would
someone encode something in this manner. What advantages does it give in
what circumstances.
R Setzer
Cat23 video
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JimK
Guest
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| Posted:
Wed Nov 09, 2005 5:41 am Post subject:
Re: Plain English explanation of direct show |
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On Tue, 08 Nov 2005 17:06:46 -0600, RS <mail@mail.com> wrote:
| Quote: | Having dug on the web a bit, I basically only found out that Directshow
is the Mikeysoft sucessor to Active Movie. Other than that, there really
is not alot of explanation that does not get into deep geek.
So, could someone explain what direct show is? When and why would
someone encode something in this manner. What advantages does it give in
what circumstances.
R Setzer
Cat23 video
|
Description from DirectShow SDK:
Microsoft? DirectShow?? is an architecture for streaming media on the
Microsoft Windows? platform. DirectShow provides for high-quality
capture and playback of multimedia streams. It supports a wide variety
of formats, including Advanced Streaming Format (ASF), Motion Picture
Experts Group (MPEG), Audio-Video? Interleaved (AVI), MPEG Audio
Layer-3 (MP3), and WAV sound files. It supports capture using Windows
Driver Model (WDM) devices or older Video for Windows devices.
DirectShow is integrated with other DirectX technologies. It
automatically detects and uses video and audio acceleration hardware
when available, but also supports systems without acceleration
hardware.
DirectShow simplifies media playback, format conversion, and capture
tasks. At the same time, it provides access to the underlying stream
control architecture for applications that require custom solutions.
You can also create your own DirectShow components to support new
formats or custom effects.
Examples of the types of applications you can write with DirectShow
include DVD players, video editing applications, AVI to ASF
converters, MP3 players, and digital video capture applications.
DirectShow is based on the Component Object Model (COM). To write a
DirectShow application, you must understand COM client programming.
For most applications, you do not need to implement your own COM
objects. DirectShow provides the components you need. (If you want to
extend DirectShow by writing your own components, however, you must
implement them as COM objects.) |
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John F. Miller
Guest
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| Posted:
Wed Nov 09, 2005 5:41 am Post subject:
Re: Plain English explanation of direct show |
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Active Movie is the older name for DirectShow.
DirectShow is one part of DirectX - others are DirectSound, DirectMusic,
DirectInput, Direct3D and DirectDraw.
The "Direct" part of the name refers to being able to write programs that
can access the computer hardware directly (e.g., the graphics card, sound
card, midi card, joystick, FireWire etc). Many moons ago - in the days of
DOS and Windows up to Me - programmers could access the hardware very easily
from their code. This makes the system very prone to bad code making a big
mess. One wrong number in the wrong place and the blue screen of death!
With Windows NT (including 2000, XP etc), the OS won't allow this and a
program trying to do it will generate an exception (and you'll see an error
on the screen and no doubt curse - but the OS is protecting itself from
further damage). The conventional way that programmers now have to access
the hardware is by making requests to the OS which, in turn, calls its own
trusted routines to do the hardware access. This is okay for simple
needs - such as sending data up and down a serial cable - but for hardware
intensive stuff, the overhead of having the OS check every request etc is
just too much. DirectX provides a trusted means of burrowing deep into the
OS and accessing the hardware and, just as importantly, in such a manner
that the application needing the access doesn't need to know the details of
the hardware. Microsoft supply a standard set of software components that
the application calls.
Much of how programmers interface with DirectX is based upon another very
important technology - COM (also known as OLE). Most people will be
familiar with this technology when, for example, embedding bits of an Excel
file in a Word document etc. ActiveX components (such as web sites like to
install on your system) use the same technology, too.
It's quite amazing (to me anyway) just how much technology is built in to an
OS like XP. Of course, most users never see it and bellyache about the
extortionate cost! Once you start programming with it, though, it makes you
realize just how much stuff there is behind the scenes.
HTH,
John.
--
John Miller
http://www.enosoft.net/
high performance tools for music and video
"RS" <mail@mail.com> wrote in message news:43712cc8$1_3@newspeer2.tds.net...
| Quote: | Having dug on the web a bit, I basically only found out that Directshow is
the Mikeysoft sucessor to Active Movie. Other than that, there really is
not alot of explanation that does not get into deep geek.
So, could someone explain what direct show is? When and why would someone
encode something in this manner. What advantages does it give in what
circumstances.
R Setzer
Cat23 video |
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Doc
Guest
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| Posted:
Wed Nov 09, 2005 5:41 am Post subject:
Re: Plain English explanation of direct show |
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"John F. Miller" <johnATenosoft.net> wrote in message
news:11n2im85cn0v0db@corp.supernews.com...
| Quote: | Active Movie is the older name for DirectShow.
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Excellent non-geek friendly explanation, thanks! |
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RS
Guest
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| Posted:
Wed Nov 09, 2005 9:25 pm Post subject:
Re: Plain English explanation of direct show |
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JimK wrote:
| Quote: |
Description from DirectShow SDK:
Microsoft? DirectShow?? is an architecture for streaming media on the
Microsoft Windows? platform. DirectShow provides for high-quality
capture and playback of multimedia streams. It supports a wide variety
of formats, including Advanced Streaming Format (ASF), Motion Picture
Experts Group (MPEG), Audio-Video? Interleaved (AVI), MPEG Audio
Layer-3 (MP3), and WAV sound files. It supports capture using Windows
Driver Model (WDM) devices or older Video for Windows devices.
DirectShow is integrated with other DirectX technologies. It
automatically detects and uses video and audio acceleration hardware
when available, but also supports systems without acceleration
hardware.
DirectShow simplifies media playback, format conversion, and capture
tasks. At the same time, it provides access to the underlying stream
control architecture for applications that require custom solutions.
You can also create your own DirectShow components to support new
formats or custom effects.
Examples of the types of applications you can write with DirectShow
include DVD players, video editing applications, AVI to ASF
converters, MP3 players, and digital video capture applications.
DirectShow is based on the Component Object Model (COM). To write a
DirectShow application, you must understand COM client programming.
For most applications, you do not need to implement your own COM
objects. DirectShow provides the components you need. (If you want to
extend DirectShow by writing your own components, however, you must
implement them as COM objects.)
|
Yes, those are the explanations I found, but none of this really gives
any particular suggestion, in real world terms why I want to go and grab
ahold of a DS codec? What will I be able to do with a DS encoded DV AVI
that I cannot do with a VFW encoded DV Avi?
So perhaps the question was misstated. Instead of 'What is it', perhaps
the more appropriate question is. "Why should I be interested?' |
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Ken Maltby
Guest
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| Posted:
Thu Nov 10, 2005 5:41 am Post subject:
Re: Plain English explanation of direct show |
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"RS" <mail@mail.com> wrote in message news:43721242$1_2@newspeer2.tds.net...
| Quote: |
Yes, those are the explanations I found, but none of this really gives any
particular suggestion, in real world terms why I want to go and grab ahold
of a DS codec? What will I be able to do with a DS encoded DV AVI that I
cannot do with a VFW encoded DV Avi?
So perhaps the question was misstated. Instead of 'What is it', perhaps
the more appropriate question is. "Why should I be interested?'
|
Perhaps you could download a copy of "GraphEdit", and
check out the "How To" guides at www.doom9.org and
www.videohelp.com or www.AfterDawn.com that mention
DirectShow or GraphEdit. A little exercise with those could
provide a practical understanding of the benefits.
Luck;
Ken |
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RS
Guest
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| Posted:
Thu Nov 10, 2005 9:47 pm Post subject:
Re: Plain English explanation of direct show |
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Ken Maltby wrote:
| Quote: | "RS" <mail@mail.com> wrote in message news:43721242$1_2@newspeer2.tds.net...
Yes, those are the explanations I found, but none of this really gives any
particular suggestion, in real world terms why I want to go and grab ahold
of a DS codec? What will I be able to do with a DS encoded DV AVI that I
cannot do with a VFW encoded DV Avi?
So perhaps the question was misstated. Instead of 'What is it', perhaps
the more appropriate question is. "Why should I be interested?'
Perhaps you could download a copy of "GraphEdit", and
check out the "How To" guides at www.doom9.org and
www.videohelp.com or www.AfterDawn.com that mention
DirectShow or GraphEdit. A little exercise with those could
provide a practical understanding of the benefits.
Luck;
Ken
|
Not much of use in any of those sites other than some deep geek
programing. All those areas begin their discussions with the assumption
that 'well duh, any C++ programmer knows this stuff!'.
I did find a somewhat better discussion in Wikipedia
http://en.wikipedia.org/wiki/DirectShow
Far as I can see, Directshow is mostly intended for media to be
delivered over the internet, and is a way to use 'filters' to allow
common translation over programming laguages. Applications can be
written that will include complex video in then for the windows platform
using Directshow and the developers will not need to incorporate
propriatary players or coding tricks to allow the contect to be viewed.
In a way, it kind of sounds like how Asp.net allows web sites to be
database interactive, or perhaps flash movies. Unless I'm really
floating off in the wrong direction, video with directshow filter
encoding will play on various windows machines without the viewer having
to have aquired a mass of codes from various sources. |
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Jona Vark
Guest
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| Posted:
Fri Nov 11, 2005 3:00 am Post subject:
Re: Plain English explanation of direct show |
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"RS" <mail@mail.com> wrote in message news:437368b4$1_2@newspeer2.tds.net...
DirectShow really doesn't have much to do with the internet. It is aprt of
the DirectX fmaily and is a higher speed alternative to standard GDI
programming. John Miller provded and excellent explanation. |
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Ken Maltby
Guest
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| Posted:
Fri Nov 11, 2005 4:18 am Post subject:
Re: Plain English explanation of direct show |
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"RS" <mail@mail.com> wrote in message news:437368b4$1_2@newspeer2.tds.net...
| Quote: | Ken Maltby wrote:
"RS" <mail@mail.com> wrote in message
news:43721242$1_2@newspeer2.tds.net...
Yes, those are the explanations I found, but none of this really gives
any particular suggestion, in real world terms why I want to go and grab
ahold of a DS codec? What will I be able to do with a DS encoded DV AVI
that I cannot do with a VFW encoded DV Avi?
So perhaps the question was misstated. Instead of 'What is it', perhaps
the more appropriate question is. "Why should I be interested?'
Perhaps you could download a copy of "GraphEdit", and
check out the "How To" guides at www.doom9.org and
www.videohelp.com or www.AfterDawn.com that mention
DirectShow or GraphEdit. A little exercise with those could
provide a practical understanding of the benefits.
Luck;
Ken
Not much of use in any of those sites other than some deep geek
programing. All those areas begin their discussions with the assumption
that 'well duh, any C++ programmer knows this stuff!'.
I did find a somewhat better discussion in Wikipedia
http://en.wikipedia.org/wiki/DirectShow
Far as I can see, Directshow is mostly intended for media to be delivered
over the internet, and is a way to use 'filters' to allow common
translation over programming laguages. Applications can be written that
will include complex video in then for the windows platform using
Directshow and the developers will not need to incorporate propriatary
players or coding tricks to allow the contect to be viewed.
In a way, it kind of sounds like how Asp.net allows web sites to be
database interactive, or perhaps flash movies. Unless I'm really floating
off in the wrong direction, video with directshow filter encoding will
play on various windows machines without the viewer having to have aquired
a mass of codes from various sources.
|
So, what you found at "VideoHelp", "Doom9" and "AfterDawn"
were "Deep Geek Programming" stuff, but you can relate to it with
your understanding of ASP .NET? Nothing Geeky, there.
The sites I listed are often of great use to total "Newbees". I
would normally think that anyone trying to understand the benefits
of Windows current multi-media interface, would have some
tolerance and affinity for what's "Geeky". ( Not to mention
someone who is comfortable with ASP .NET applications or
services.)
I also think that Mr. Miller's explanation was an excellent
overview of the concepts involved, at a level that closely
matches your request. My post was directed as providing
a means to acquire some actual practical experience
manipulating the concepts, this is IMHO often needed to
gain any real understanding. The tool and sites I mentioned
were provided, in part, just because they are the least
"Geeky" approach.
Luck;
Ken
P.S. You might consider "GraphEdit" as like a "Visual"
type of tool, something akin to using "Visual C#" or
"Visual Basic .NET" to write ASP .NET; only much,
much simpler. |
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