RE: [libdv-dev] Re: [Kino-dev] DV output - data points

[Arne S. <ar...@sc...>]

Can you explain exactly when the incorrect sound appears? At playback of an 
AVI under Linux or Windows, using what program? Or after playing back a 
tape on the camcorder that has been recorded with DV export? I don't fully 
understand your description; in particular why you have this problem also 
in raw mode, where no audio code is involved.

The difference between AVI type 1 and type 2 is that both Kino and dvgrab 
attempt to decode the audio data and put it into separate blocks in the AVI 
file. This is for some Windows programs that expect both a video and an 
audio track in the AVI file. As there are many possible audio formats (12 
bit, 16 bit, 2 channels, 4 channels and other features), it looks as if I 
did not got all combinations right.

Arne





-----Original Message-----
From:	Alastair Mayer
Sent:	Wednesday, May 30, 2001 11:00 PM
To:	Dan Dennedy
Cc:	lib...@li...; Kin...@li...; Kirk I 
Reiten
Subject:	[libdv-dev] Re: [Kino-dev] DV output - data points

More (audio) data points -- see below

Dan Dennedy wrote:
>
> Thanks for the feedback. I am commiting to CVS a new version of Kino
> tomorrow night that will expose the various timing constants for DV 
export
> in the Preferences dialog (the preferences will also save between 
sessions).
> This will let you experiment to get a good output. Also, I have noticed 
on
> my AMD 333 development machine, that the updating of the progress bar
> interferes with export, so I will either provide a toggle in preferences 
or
> see if a simple textual "current frame #/total frames" feedback is less
> intrusive.

Cool.  Although for my work-related app I may not use Kino -- see below
--
but I'll be using it for home video editing.

> Alastair, it is normal for your device to take a few seconds to "synch" 
up
> before displaying the video. Therefore, I have on the Kino task list to
> revise DV export to display the first frame for a few seconds before
> continuing.

Sounds reasonable -- testing the DV-bridge with longer clips it does
seem
to pretty consistently take about 5 seconds before the analog stream
appears, but if I cat multiple clips together (eg cat *.dv|dvconnect -s)
there's only a brief blank between clips.

And I have more data points from playing with dvgrab, Kino, and
dvconnect,
all with the Dazzle Hollywood DV bridge in NTSC.   The video stream
looks
okay on longer clips, but I'm getting weird audio effects in some cases
(on export).

Specifically, capturing in Kino AVI 2 mode and playing back, or
capturing
with dvgrab or Kino in raw mode and exporting with dvconnect, I get
garbled audio -- some sort of periodic noise or chirp mixed with the
audio.
I don't get this if I capture/export with Kino AVI 1, or capture raw DV
with dvconnect and export with dvconnect -s.   Clean audio in both those
cases.  (The machine I'm currently working on doesn't have an audio card
so I can't test what it sounds like played back on the PC.)

Since there's a way to get clean audio in AVI (mode 1) or raw DV (with
dvconnect) that's a low priority for me, just thought I'd mention it.

I'm probably going to end up with some hybrid of the Kino playlist and
dvconnect's export of DV files, since that's what I need for the project
I'm currently being paid to work on.  (Dynamic creation of videotapes
from
a library of clips.  Currently we're using expen$ive analog cards on
NT.)

-- Alastair

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