Re: controling a video recorder ?

[Dan D. <dde...@co...>]

Your abstract VFrameGrabber class would enable something like Broadcast 2000
to record from a raw dv file as created by dvgrab?

I think the biggest performance gain can be made by using the DMA iso
receive as defined in video1394. Does this mean the dv decoder must keep up
with the isochronous channel? If so, perhaps it fails over to the non-DMA,
buffered iso receive defined in raw1394.

When you say you are using a "window into the image," do you mean that you
doing rectangular clipping?

Right now, I am interested in two things with creation of a class framework:
standardize an interface to various codecs and integrate AVC with video
capture. Also, iso transmit of dv would be great!

----- Original Message -----
From: "Chateau Thierry" <thi...@la...>
To: "Dan Dennedy" <dde...@co...>
Cc: "Andreas Micklei" <and...@iv...>; "1394 user"
<lin...@li...>
Sent: Tuesday, October 24, 2000 3:22 AM
Subject: Re: controling a video recorder ?


Your idea for a collection of 1394-related classes is very good. Actually, I
try to write a C++ collection of class for Video. It is in very alpha way
for
the moment but I have developped an abstract class called VFrameGrabber and
two
child classes: one for ieee1394 DV  Video Recorder and one for DV File. I
also
want to implement IEEE Camera using libdc and other devices (not only
connected
to 1394 because the target is to write tools for image processing). For the
moment, I use libraw, libdc (modified because there are some variables
called
classes or private and I prefer remaning its). I also tried, yesterday,
simpleavc.h from gscanbus which work fine but I will test SDPAVC.
On my PIII 733 with 256M Ram, dv decoding (from libdv) for a Pal format
takes
40 ms. (In the same time, an another thread for isochonous reception on the
1394 bus is working). I change the source of dv_decode in order to decode
only
a window into the image ; so, it takes less time. Do you think that other
improvements may be done in order to reduce dv decoding time ?