Re: Unsychronous recording from DV cameras
- From: enze <enze@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Wed, 12 Apr 2006 23:42:01 -0700
Hi Thore,
i like to get more detailed information about this
device and resulting sync problem.
I have special version of our Mux filter along
with log module.
Using this creates detailed log file during capture which
helps me to see the reason for loosing a/v sync.
Please send email contact to info@xxxxxxxxxxxx,
regards, enze
"Thore Karlsen [DShow MVP]" wrote:
On Wed, 12 Apr 2006 08:30:01 -0700, enze.
<enze@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Since the video and audio are
separate devices, they use use different clocks, and chances are they
will drift slightly. So after an hour they might be a second out of
sync, after two hours they might be two seconds out of sync
Right, i posted same before
I have tried
all kinds of solutions (mine and others), and nothing I have seen has
worked particularly well.
Did you also tried our actual CapSwitchFilter's ?
I have not been told about problems until now,
our a/v synchronization accuracy is 2-3ms/h .
Yes, I did try it, and unfortunately, the audio was very out of sync
with the video. Several seconds out of sync after only half an hour.
Also, the audio sample information on the statistics page stopped
updating after about 45 minutes, and the portion of the file in which
the audio samples appeared to stop arriving was not playable.
This was with an AverMedia Cardbus PCMCIA card (using a PCMCIA adapter
card in my desktop system), and I set up a simple graph in GraphEdit
which was basically just the AverMedia source filter connected to your
mux, and I configured your mux to write to an AVI file. Then I let it
run for about an hour.
What is interesting about this is that I believe the AverMedia uses the
Philips SAA713x capture chip, and the specs for the chip says this:
"A field-locked audio clock samples a constant number of audio clocks
per video field, guaranteeing synchronization between audio and video
streams."
Other things I tried:
- Plain DirectShow capture graph with AVI mux: Didn't work, regardless
of whether I set the master stream or not. A second or two out of sync
after an hour.
- VirtualVCR: Didn't work, regardless of whether I enabled audio
resampling or not.
- VirtualDub: Did not work if I didn't enable audio resampling. Did a
pretty good job if I enabled audio resampling, but not perfect.
- Application that came with the card: Sync seemed to be perfect, but I
found some Philips DLLs that can be used to access the card directly,
and I'm wondering if they're doing that instead of using DirectShow. I'm
not sure exactly what they are doing.
In all cases, audio and video were perfectly synchronized with no
noticeable latency on preview. That might be because of rate matching in
the DirectSound renderer, I don't know.
I also tried another card with the same chipset, and got the same
results. Same thing with some USB devices I've tried before. It's all
very depressing.
--
New to newsgroups? Read: http://dev.6581.com/newsgroups.html
- References:
- Re: Unsychronous recording from DV cameras
- From: Tsviatko Jongov
- Re: Unsychronous recording from DV cameras
- From: Tsviatko Jongov
- Re: Unsychronous recording from DV cameras
- From: Peter Feldbaumer
- Re: Unsychronous recording from DV cameras
- From: Thore Karlsen [DShow MVP]
- Re: Unsychronous recording from DV cameras
- From: Thore Karlsen [DShow MVP]
- Re: Unsychronous recording from DV cameras
- Prev by Date: Re: Audio/Video Mux filter Interfaces / threads
- Next by Date: how to fade video in audiovideoplayback
- Previous by thread: Re: Unsychronous recording from DV cameras
- Next by thread: Re: Unsychronous recording from DV cameras
- Index(es):
Relevant Pages
|
