Technology and Trends
 Linux Video & DVD Project Mailing List Archives
  
List:       linux-video
Subject:    Video grabbing
From:       Alexei Dets <dets () china ! formoza ! ru>
Date:       2000-03-14 8:36:05

Hi!
Does anybody know about any V4L application that can grab video with
compression (ex. mjpeg or mpeg) and have no problems with video/audio
sync?
For now I've tried:
1) kwintv - no compression;
2) xawtv - no sync;
3) mp1e - no sync;
4) bttvgrab - unusable.
Under Windows I can grab video at 640x480x25 fps with mjpeg compression
without any problems (or, no, with one serious problem - no more than 21
min. at once, I don't know why). I have LifeView FlyVideo'98 FM card
(bt878) & PII-300 PC.

	WBW, Alexei Dets


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Alan Cox <alan () redhat ! com>
Date:       2000-03-14 13:27:53

> 4) bttvgrab - unusable.
> Under Windows I can grab video at 640x480x25 fps with mjpeg compression
> without any problems (or, no, with one serious problem - no more than 21
> min. at once, I don't know why). I have LifeView FlyVideo'98 FM card
> (bt878) & PII-300 PC.

Broadcast 2000 will grab with sync. I've used it to make avi files so I can
watch a TV program later, and on a 40 minute tv file it was fine.

Alan


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       "Eric Boehm" <boehm () nortelnetworks ! com>
Date:       2000-03-14 14:30:24

>>>>> "Alan" == Alan Cox <alan@redhat.com> writes:

    Alan> Broadcast 2000 will grab with sync. I've used it to make avi files
    Alan> so I can watch a TV program later, and on a 40 minute tv file it was
    Alan> fine.

Wasn't the resulting file huge? I have had trouble grabbing (under Linux)
camcorder (8mm) output using xawtv (AverMedia TV Stereo 98 card). I did
eventually grab it under Windows 98 using the AverMedia software but the
resulting 2 minute AVI file was huge (200MB).

I was hoping to send the clip via email to my father but that's just too big.

Any suggestions or ideas would be appreciated?

-- 
Eric M. Boehm                               boehm@nortelnetworks.com


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Gerd Knorr <kraxel () goldbach ! in-berlin ! de>
Date:       2000-03-14 22:08:19

> Wasn't the resulting file huge? I have had trouble grabbing (under Linux)
> camcorder (8mm) output using xawtv (AverMedia TV Stereo 98 card). I did
> eventually grab it under Windows 98 using the AverMedia software but the
> resulting 2 minute AVI file was huge (200MB).

Uncompressed?  Try using mjpeg.  /me has a 15 min movie (320x240 / 25 fps),
it has 310 MB ...

BTW: xawtv 3.10 has largely rewritten avi recording code and should do a
better job at keeping audio+video in sync (as long as your box is fast
enouth to handle the load, it can't handle dropped frames yet...)

  Gerd

-- 
Protecting the children is a good way to get a lot of adults who cant
stand up for themselves.		-- seen in some sig on /.


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Malcolm Caldwell <malcolm () it ! ntu ! edu ! au>
Date:       2000-03-16 2:53:34

On Tue, Mar 14, 2000 at 08:27:53AM -0500, Alan Cox wrote:
> > 4) bttvgrab - unusable.
> > Under Windows I can grab video at 640x480x25 fps with mjpeg compression
> > without any problems (or, no, with one serious problem - no more than 21
> > min. at once, I don't know why). I have LifeView FlyVideo'98 FM card
> > (bt878) & PII-300 PC.
> 
> Broadcast 2000 will grab with sync. I've used it to make avi files so I can
> watch a TV program later, and on a 40 minute tv file it was fine.

What kind of card and what are the specs of the machine you did this on?

> Alan
> 
> 
> -- 
>          To unsubscribe: mail video4linux-list-request@redhat.com with 
>                        "unsubscribe" as the Subject.

-- 
Malcolm Caldwell - Manager, IT Infrastructure     Email:malcolm@it.ntu.edu.au
Information Technology Support                    Ph:  +61 8 89466631
Northern Territory University,Darwin              Fax: +61 8 89466630
CASUARINA 0909 Australia


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Alan Cox <alan () redhat ! com>
Date:       2000-03-16 3:17:51

> > Broadcast 2000 will grab with sync. I've used it to make avi files so I can
> > watch a TV program later, and on a 40 minute tv file it was fine.
> 
> What kind of card and what are the specs of the machine you did this on?

256Mb K7/550 with a 5 disk hardware raid array. I'd probably go for
a faster CPU by choice but that was then this is now 8)


Alan



-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Alexei Dets <dets () china ! formoza ! ru>
Date:       2000-03-16 9:10:52

Hi!
Alan Cox wrote:
> 
> > 4) bttvgrab - unusable.
> > Under Windows I can grab video at 640x480x25 fps with mjpeg compression
> > without any problems (or, no, with one serious problem - no more than 21
> > min. at once, I don't know why). I have LifeView FlyVideo'98 FM card
> > (bt878) & PII-300 PC.
> 
> Broadcast 2000 will grab with sync. I've used it to make avi files so I can
> watch a TV program later, and on a 40 minute tv file it was fine.

Very strange. I got the sources of Broadcast2000, compiled them and try
to do capture video.
It works very, VERY slow - maximum 352x288x17fps with jpeg compression.
No sync at all! More over, sometimes even sound got lost. For instance,
mp1e can do _realtime_ _mpeg_ video capture with 352x288x30 fps on the
same PC and have _small_ desynchronisation between audio/video (but this
is not acceptable for long records). Are where any configuration
secrets?
I'm using bttv-0.7.17 with 4 capture buffers. May be I must try to use
v4l2, or they are basically the same at the part of sync?

	WBW, Alexei


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Justin Schoeman <justin () suntiger ! ee ! up ! ac ! za>
Date:       2000-03-16 9:34:40

Alexei Dets wrote:
> 
> Hi!
> Alan Cox wrote:
> >
> > > 4) bttvgrab - unusable.
> > > Under Windows I can grab video at 640x480x25 fps with mjpeg compression
> > > without any problems (or, no, with one serious problem - no more than 21
> > > min. at once, I don't know why). I have LifeView FlyVideo'98 FM card
> > > (bt878) & PII-300 PC.
> >
> > Broadcast 2000 will grab with sync. I've used it to make avi files so I can
> > watch a TV program later, and on a 40 minute tv file it was fine.
> 
> Very strange. I got the sources of Broadcast2000, compiled them and try
> to do capture video.
> It works very, VERY slow - maximum 352x288x17fps with jpeg compression.
> No sync at all! More over, sometimes even sound got lost. For instance,
> mp1e can do _realtime_ _mpeg_ video capture with 352x288x30 fps on the
> same PC and have _small_ desynchronisation between audio/video (but this
> is not acceptable for long records). Are where any configuration
> secrets?
> I'm using bttv-0.7.17 with 4 capture buffers. May be I must try to use
> v4l2, or they are basically the same at the part of sync?

The v4l2 driver uses more buffers, and also timestamps each buffer as it
is captured (which is not possible in v4l).  The timestamping gives
marginally better results.  Many buffers help a lot more, as mp1e looses
sync when frames are dropped.  With a good .5s of buffer, I never get
dropped frames.

-justin


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Alan Cox <alan () redhat ! com>
Date:       2000-03-16 13:09:09

Old BT848 card


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Alan Cox <alan () redhat ! com>
Date:       2000-03-16 13:15:27

> mp1e can do _realtime_ _mpeg_ video capture with 352x288x30 fps on the
> same PC and have _small_ desynchronisation between audio/video (but this
> is not acceptable for long records). Are where any configuration
> secrets?

I'd love to know how you got MP1E working. I can get it capturing nicely
but the players all bork on the output.

> I'm using bttv-0.7.17 with 4 capture buffers. May be I must try to use
> v4l2, or they are basically the same at the part of sync?

Im using V4L1. V4L2 might help although bcast2000 could easily get
the saem effect from BTTV_FRAMENUM. I've also got an Iomega buz mjpeg card
and lavtools. I have to find a box that likes it then experiment further
(the bridge on it doesnt seem to agree with my dual P90)

Alan


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Justin Schoeman <justin () suntiger ! ee ! up ! ac ! za>
Date:       2000-03-16 13:30:43

Alan Cox wrote:
> 
> > mp1e can do _realtime_ _mpeg_ video capture with 352x288x30 fps on the
> > same PC and have _small_ desynchronisation between audio/video (but this
> > is not acceptable for long records). Are where any configuration
> > secrets?
> 
> I'd love to know how you got MP1E working. I can get it capturing nicely
> but the players all bork on the output.

The only Linux player I have found that works properly if MpegTV.  None
of the others seem to work.  Oddly enough, all the windoze players work
though...

> > I'm using bttv-0.7.17 with 4 capture buffers. May be I must try to use
> > v4l2, or they are basically the same at the part of sync?
> 
> Im using V4L1. V4L2 might help although bcast2000 could easily get
> the saem effect from BTTV_FRAMENUM. I've also got an Iomega buz mjpeg card
> and lavtools. I have to find a box that likes it then experiment further
> (the bridge on it doesnt seem to agree with my dual P90)
> 
> Alan

Unfortunately BTTV_FIELDNR isn't a v4l ioctl, and isn't included in any
of the "external" include files. (In fact last time I tried to include
bttv.h from a user app the compiler gave so many errors I didn't know
where to start!

What about defining a v4l extension to allow timestamping?  A simple
proposal:

1) Add a capability flag VID_TYPE_SYNC
2) Timestamp frames as they are captured.
3) Use a new (say VIDIOCSYNC2) ioctl to get a captured frame and return
the timestamp.

I would be willing to add these extensions to the bttv driver if there
was some agreement on exactly how the extension should be implemented.

Another aspect is the timestamp itself.  Will UST ever be included in
the kernel, or should timestamps be made by do_gettimeofday?

-justin


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.

List:       linux-video
Subject:    Re: Video grabbing
From:       Alan Cox <alan () redhat ! com>
Date:       2000-03-16 13:42:45

> > I'd love to know how you got MP1E working. I can get it capturing nicely
> > but the players all bork on the output.
> 
> The only Linux player I have found that works properly if MpegTV.  None
> of the others seem to work.  Oddly enough, all the windoze players work
> though...

So its nonfree as a aset and useless to me

> 1) Add a capability flag VID_TYPE_SYNC
> 2) Timestamp frames as they are captured.
> 3) Use a new (say VIDIOCSYNC2) ioctl to get a captured frame and return
> the timestamp.
> 
> I would be willing to add these extensions to the bttv driver if there
> was some agreement on exactly how the extension should be implemented.
> 
> Another aspect is the timestamp itself.  Will UST ever be included in
> the kernel, or should timestamps be made by do_gettimeofday?

The advantage of using do_gettimeofday is on a modern machine its usecond
or nanosecond accuracy.

Adding timestamps I dont have a problem with, ditto field number. In fact I
had promised to do that ages ago and forgot


Alan


-- 
         To unsubscribe: mail video4linux-list-request@redhat.com with 
                       "unsubscribe" as the Subject.