Re: Combining video+audio clips ?

On Sun, 09 Sep 2007 20:15:22 GMT, in 'rec.video.desktop',
in article <Re: Combining video+audio clips ?>,
"RedFox" <somewun@xxxxxxxxxxxxx> wrote:


"Frank" <frank@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:udq5e35e9t889c3b6fmareq79n2fg9344j@xxxxxxxxxx
On Sat, 08 Sep 2007 08:59:11 +0100, in 'rec.video.desktop',
in article <Re: Combining video+audio clips ?>,
Martin Heffels <goofie@xxxxxxxxxxx> wrote:

On Fri, 07 Sep 2007 23:30:33 -0400, Frank
<frank@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

All what Frank said, except....

Have you looked at these files in a hex editor program to determine
whether or not they're really Apple QuickTime .mov files?

Use G-spot. Much easier to understand than a bunch of hex ;-)
http://www.headbands.com/gspot/

Agreed ( although us old programmers actually *like* "a bunch of hex"
:) ), and although GSpot is really designed to examine .avi files, it
will display information about .mov files. I just tried an
AVC/AAC-encoded .mov, for example, and it gave me fairly complete
information. It doesn't determine codec status, however, probably
because it lacks code to determine which QuickTime compatible codecs
are installed on the system.

Apple, however, offers an old program called Dumpster that will
display the internal structure of a .mov file. I would think that if
the files that the OP is trying to play (that the QuickTime Player
program "doesn't recognize as videos") are not really .mov files, the
Dumpster program would also complain. OTOH, if they really are valid
.mov files, then Dumpster should display their structure.

The Windows version of the Dumpster program can be downloaded for free
via the following link.


ftp://ftp.apple.com/developer/Quicktime/Windows_Tools/Programmers_Tools/Dump
ster/Dumpster.zip

Just for the record, Microsoft offers a similar free program for .asf,
.dvr-ms, .wm, .wma, and .wmv files called Windows Media ASF View 9
Series (asfview.exe). Information about the program, as well as a link
to download it, can be found at the following URL.


http://www.microsoft.com/windows/windowsmedia/forpros/format/asfviewer.aspx

--
Frank, Independent Consultant, New York, NY

Thank you Frank and Martin for your help.

You're very welcome.

Win2K has SP4 + Rollup installed

Excellent, but I do hope that you visit Windows Update/Microsoft
Update once a month and download and install *all* updates, critical
or not (except for device driver updates, which seem to cause more
problems for people than they fix).

The second Tuesday of each month is Microsoft "Patch Tuesday" and
that's when the updates are normally issued.

I used GSpot, as you suggested, and it indicated the files as MPEG-2 video
and AC3 audio but that the AC3 codec was not installed. So you were right
Frank. That was the reason for no audio......

Okay.

but why is it that I can hear
the audio in the individual files but not when I combine them?

And this is happening in the same program, or in different programs?
Remember, different programs will use different methods to playback
the audio and video streams contained within the file, so what works
in one program may well not work in another.

VLC and
other progs play both audio and video in the individual clips.

Okay, that's good. VLC comes with a large variety of built-in codecs.
These codecs are only usable within the VLC media player program
itself. They are not usable elsewhere, such as in Windows Media
Player, for example.

Apple products don't concern me too much; it just happened that I had
Quicktime installed. I'm sure there are many more progs for windoze. I have
many video players already.

For anyone doing extensive multimedia-related work, especially when
they must be in a position to accept files from diverse, sometimes
unknown, sources, having many multimedia player programs, and a large
collection of codecs installed, is sort of a necessity, although I do
not recommend the use of so-called "codec packs". It's usually better
(safer) to install individual codecs on as-needed basis.

I had AC3 running on an earlier Win2K installation but, although I have a
lot of AC3 files, I don't see the codec. I have AC3 filter, AC3 ACM but no
trace of anything called codec.
It would appear that the AC3 is the problem.

In the Windows world, generally speaking (the Apple QuickTime Player
program and other QuickTime-based applications are an exception to
what follows), audio codecs come in three basic flavors. (Note that
"codec" simply means coder/decoder or compressor/decompressor - old
telco terminology.)

Firstly, there are old-style ACM (Audio Compression Manager) codecs.
These usually have a .acm extension and usually reside in the Windows
System directory (C:\WINNT\system32 on most systems). ACM has been
around since the days of Win3.x.

A second type is the so-called DirectShow codec, which is really a
type of DirectShow filter. (DirectShow is a part of what's called
DirectX, something that you most always want to keep up to date).

DirectShow filters often, but not always, have a .ax file extension
and often, but not always, reside in the Windows System directory
(C:\WINNT\system32 on most systems). DirectShow filters must be
"registered" on the system in order to be used. The register server
program (RegSvr32.exe) program performs this function.

DirectShow filters come in many flavors for performing a variety of
tasks. There are DirectShow filters that act as file readers, file
parsers, demultiplexers, multiplexers, audio decoders, audio encoders,
video encoders, video decoders, overlay providers, color converters,
renderers, splitters, just to name a few of the more commonly found
functions.

DirectShow filters that act as audio or video encoders or as audio or
video decoders are codecs. If audio, they are codecs implemented in
the form of a DirectShow filter instead of in the form of an ACM
codec, but they're still codecs in terms of their basic functionality.

The third major type of audio codec in the Windows world is the
"dedicated codec", for lack of a better term. These codecs typically
are included with a particular application and are tied to that
application; that is, they're not accessible to any other applications
that might happen to be installed on the system. The codecs that are
included with the VideoLAN VLC media player program represent a good
example of this. They can only be used by the VideoLAN VLC media
player program and not by any other applications.

ACM codecs, and DirectShow filters in general (whether audio codecs or
not), can be used by most any application which was written in such a
way as to support ACM codecs and/or DirectShow filters. Windows Media
Player is a fairly good example of this, as it will tend to use any
appropriate DirectShow filters that might happen to be installed on
the system.

In a similar fashion, VirtualDub is a good example of a program that
will tend to use any ACM codecs that might happen to be installed on
the system. In fact, VirtualDub will not use DirectShow filters, even
if the only installed codec required to play back a certain media file
happens to be a DirectShow codec. This is why it's often
necessary/desirable to have two different codecs, both of which handle
the same type of audio encoding, simultaneously installed on the
system -- because certain applications will want to use the ACM
version of the codec while other applications will want to use the
DirectShow filter version of the codec.

Also, note that in a case such as this, the two different versions of
the codec, one ACM and one DirectShow, need not have come from the
same source (that is, have been written by the same author/company).
One could have been written by a private individual or individuals, as
are many open source codecs, and the other could have been published
by a large software company.

The situation with video codecs is similar to that for audio codecs,
except that instead of the ACM architecture, we have the VCM (Video
Compression Manager) architecture.

If I had time, I'd cover managing codec conflicts, which occur when
two codecs of the same type (ACM and audio DirectShow or VCM and video
DirectShow) are both installed simultaneously on a given system, but I
don't, so that will have to wait for another day.

I have dnloaded VDubMod Mpeg but have not used it yet. Will try soon.

I'm tempted to say, "Hope that it works for you!", but if you're
dealing with a .mov file, VirtualDub-MPEG2 will not help. Did you ever
try the Dumpster program that I recommended?

Thanks again and I hope you're enjoying the weekend :-)

It would help if I could get some sleep. :)

RF

--
Frank, Independent Consultant, New York, NY
[Please remove 'nojunkmail.' from address to reply via e-mail.]
Read Frank's thoughts on HDV at http://www.humanvalues.net/hdv/
(also covers AVCHD and XDCAM EX).
.

Relevant Pages

  • Re: Combining video+audio clips ?
    ... Update once a month and download and install *all* updates, ... VLC comes with a large variety of built-in codecs. ... DirectShow filters often, but not always, have a .ax file extension ...
    (rec.video.desktop)
  • Re: Combining video+audio clips ?
    ... Update once a month and download and install *all* updates, ... VLC comes with a large variety of built-in codecs. ... DirectShow filters often, but not always, have a .ax file extension ...
    (rec.video.desktop)
  • Re: Combining video+audio clips ?
    ... whether or not they're really Apple QuickTime .mov files? ... Update once a month and download and install *all* updates, ... VLC comes with a large variety of built-in codecs. ... DirectShow filters often, but not always, have a .ax file extension ...
    (rec.video.desktop)
  • Re: Combining video+audio clips ?
    ... the audio and video streams contained within the file, ... VLC comes with a large variety of built-in codecs. ... DirectShow filters often, but not always, have a .ax file extension ... PS, if you have problems sleeping, I have the answer - exercise. ...
    (rec.video.desktop)
  • Re: wave with 96000hz 24bit
    ... It uses ACM to resample. ... If the sound card install adds it's *own* ACM driver then yes it is ... You can see all the audio ACM codecs on the system by looking under "Sounds ...
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