Re: size of DV/1394 video stream

On Mon, 27 Jun 2005 12:37:34 -0700 Richard Crowley <rcrowley7@xxxxxxxx> wrote:
| phil-news-nospam wrote ...
|> On Mon, 27 Jun 2005 09:52:02 -0700 Richard Crowley
|> <rcrowley7@xxxxxxxx> wrote:
|> | phil-news-nospam wrote ...
|> |> Richard Crowley wrote:
|> |> | All you need to do is have some external method of identifying
|> |> | the file as a DV bitstream. That is why RIFF, AVI, MOV, etc.
|> |> | formats were invented. They use a miniscule part of the file to
|> |> | internally identify the file encoding (aka. "codec')
|> |>
|> |> Why would the extension on the file name, such as ".dv" not be
|> |> enough?
|> |
|> | Because it can be changed (or even removed) by the user. But then
|> | we have no idea what the application/situation is so only you know
|> | whether this is an issue or not.
|>
|> Why would someone do that?
|
| Wrong question.
| The issue isn't *why* a user could do it, but *can* they do it.

I disagree. A user *can* delete a file, too. A user *can* delete all
the files and even the software. It is not my responsibility to protect
everything from stupid users. But at least with renamed files, if they
break it, they can fix it (rename it back).

If I restrict users to only working through my software (e.g. no shell
or file manager interface) then I can prevent them from renaming the
extension (and in fact I can hide it and they only work on the base
name).


|> | You will get lots of irrelevant info when you have such an
|> unstructured
|> | and context-free question. If you want to play 20 questions maybe
|> | you can find a fun-n-games newsgroup somewhere.
|>
|> As long as I don't know what is actually in the AVI format, I'm not
|> going to be able to phrase very good questions for it.
|
| Then study the specs for AVI.

I'm not convinced it is worth the hassle.


|> Aside from
|> being able to share with NLEs, I see no reason to add any more to
|> the DV stream than what comes over the wire.
|
| NLEs don't require anything to be added. DV codecs don't add
| (or delete) anything.
|
|> But if I do use a file format that is different than DV, it would
|> have to be something that I can use as well as at least one major
|> NLE.
|
| DV isn't a file format. It is a video encoding standard and codecs
| are used to define how DV is handled in a file.

I've managed find (with the help of Google) and download some DV files
already. So I'd say they do exist (downloaded about 200 MB already,
but I can't view them, yet). I've got libdv and am preparing to
compile and install it (even though I do not have a firewire card or
converter, yet).

I may just go ahead and buy a convert for myself. Maybe you will at
least agree with me that the ADVC-110 would be a fine choice.


|> If no, then we have to be talking about specific codecs. I think the
|> answer has to be yes, but the way you have been referencing it, I
|> cannot
|> rule out that the answer could be no.
|
| A "DV codec" is expected to be able to defiine how to decode and
| encode a DV bitstream. There is more than a single way of doing
| this and that is why there are different codecs.

Far too many ways, if you ask me.


|> It would be easier to discuss AVI if there was more info on details of
|> how it works. How much of it do you know and have documented? At the
|> very least, can you say what bytes (number or string?) are in the AVI
|> file to identify the "DV" codec? Is it "DV" or 17494 or 22084?
|
| OK, since you can't seem to do your own research, here is a start...
| http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/directx9_c/directx/htm/avirifffilereference.asp

Seems Microsoft doesn't like the fact that I am accessing their site
using a Linux based computer. It redirected me to:

http://msdn.microsoft.com/library/shared/deeptree/bot/bot.asp?dtcnfg=/archive/deeptreeconfig.xml

which seems to be a fairly mundane menu. There is a "graphics and
media" link, so I went there, and got taken to:

http://msdn.microsoft.com/library/shared/deeptree/bot/bot.asp?xmlsrc=/archive/en-us/toc/msdnarchive/msdnarchive62_.xml

Now there are a lot more links. Nothing about AVI, but there is a
link "Multimedia (General)" so I follow that which takes me to:

http://msdn.microsoft.com/library/shared/deeptree/bot/bot.asp?xmlsrc=/archive/en-us/toc/msdnarchive/msdnarchive120_.xml

The problem here is I get a message that their server has a programming
issue:

An error occurred on the server when processing the URL. Please contact
the system administrator. An error occurred on the server when processing
the URL. Please contact the system administrator.

What? A programming error at Microsoft? How can that be?

I've already found other links to better places at Microsoft. But the
only file that hints at giving details about AVI is in .doc format, which
does not work for me. I tried renaming it to .pdf and that didn't work,
either.

Is this "RIFF" format the same one that was really invented for the Amiga
and stolen by Microsoft which subsequently claims they invented it, just
like they do with everything else (after adding bugs)?

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------
.

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