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Dropped Frame always at 3:20

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April 8, 2005 1:01:16 AM

Archived from groups: rec.video.desktop (More info?)

Hi,

I'm trying to capture analog video with a AIW9800 and a Audigy2 sound
card from the S-Video out on a DVR with VirtualDub. The problem is I'm
getting random dropped frames with the exception of one dropped frame
always at 3 minutes and 20 seconds. I'm capturing using AVI Huffy v2.20
at 720x480 and PCM audio at 44.1KHz.

Overall the captures work, but it would be nice to not to see any or as
many, dropped frames. I've tried just about everything I can think of to
reduce dropped frames, including a capture at 160x120 with 8KHz mono
audio which still produced dropped frames.

I turned off 'add NULL' frames and 'Drop frames when to close' in the
Timing Options and while there were no longer any dropped frames, the
sound after a short while was out of sync.

The system is a 3.0GHz P4 and the capture drive is a NTFS 250GB drive
that is empty and sits on its own Promise 133 controller. I've disable
the audio capture in VirtualDub, still dropped frames. I've done a
VirtualDub "Test" capture (doesn't involve the hard drive), still
dropped frames. Turned off the audio and a "Test" capture and still
there are dropped frames. I've end tasked everything that is in XP Pro's
Task Manager as to see only the bare minimum running and even unplugged
the NIC cable and there are still dropped frames.

Since the source is a DVR, I can start and end the capture in the exact
same place. So in a ten minute capture there could be 10 dropped frames,
but the next time (not changing any settings) there could be 15 dropped
frames. But one thing that always doesn't changes, a dropped frame at 3
minutes and 20 seconds.

Does anyone know why 3:20 would be some magical spot for a dropped frame
on every capture?

--

Tom

More about : dropped frame

Anonymous
April 8, 2005 2:53:34 AM

Archived from groups: rec.video.desktop (More info?)

Is it really dropping the *frame* at 3:20, or is it dropping
the *timecode* at that frame? Any chance that you have
tape that was shot with "dropframe timecode"?
April 8, 2005 6:41:20 AM

Archived from groups: rec.video.desktop (More info?)

Tom wrote:
> Hi,
>
> I'm trying to capture analog video with a AIW9800 and a Audigy2 sound
> card from the S-Video out on a DVR with VirtualDub. The problem is I'm
> getting random dropped frames with the exception of one dropped frame
> always at 3 minutes and 20 seconds. I'm capturing using AVI Huffy v2.20
> at 720x480 and PCM audio at 44.1KHz.
>
> Overall the captures work, but it would be nice to not to see any or as
> many, dropped frames. I've tried just about everything I can think of to
> reduce dropped frames, including a capture at 160x120 with 8KHz mono
> audio which still produced dropped frames.
>
> I turned off 'add NULL' frames and 'Drop frames when to close' in the
> Timing Options and while there were no longer any dropped frames, the
> sound after a short while was out of sync.
>
> The system is a 3.0GHz P4 and the capture drive is a NTFS 250GB drive
> that is empty and sits on its own Promise 133 controller. I've disable
> the audio capture in VirtualDub, still dropped frames. I've done a
> VirtualDub "Test" capture (doesn't involve the hard drive), still
> dropped frames. Turned off the audio and a "Test" capture and still
> there are dropped frames. I've end tasked everything that is in XP Pro's
> Task Manager as to see only the bare minimum running and even unplugged
> the NIC cable and there are still dropped frames.
>
> Since the source is a DVR, I can start and end the capture in the exact
> same place. So in a ten minute capture there could be 10 dropped frames,
> but the next time (not changing any settings) there could be 15 dropped
> frames. But one thing that always doesn't changes, a dropped frame at 3
> minutes and 20 seconds.
>
> Does anyone know why 3:20 would be some magical spot for a dropped frame
> on every capture?

Could it be the complexity of the video at the 3:20 point in the show? Try
capturing only that segment of video. Plus minus a minute and see what happens.
Do this two or three times and see if the dropped frames occur in the same
place.
Related resources
April 8, 2005 10:59:38 AM

Archived from groups: rec.video.desktop (More info?)

DanR <dhr22@sorrynospm.com> wrote in
news:kbm5e.2883$3z3.2040@newssvr12.news.prodigy.com thusly:

>> I'm trying to capture analog video with a AIW9800 and a Audigy2 sound
>> card from the S-Video out on a DVR with VirtualDub. The problem is
>> I'm getting random dropped frames with the exception of one dropped
>> frame always at 3 minutes and 20 seconds. I'm capturing using AVI
>> Huffy v2.20 at 720x480 and PCM audio at 44.1KHz.
>>
>> Overall the captures work, but it would be nice to not to see any or
>> as many, dropped frames. I've tried just about everything I can think
>> of to reduce dropped frames, including a capture at 160x120 with 8KHz
>> mono audio which still produced dropped frames.
>>
>> I turned off 'add NULL' frames and 'Drop frames when to close' in the
>> Timing Options and while there were no longer any dropped frames, the
>> sound after a short while was out of sync.
>>
>> The system is a 3.0GHz P4 and the capture drive is a NTFS 250GB drive
>> that is empty and sits on its own Promise 133 controller. I've
>> disable the audio capture in VirtualDub, still dropped frames. I've
>> done a VirtualDub "Test" capture (doesn't involve the hard drive),
>> still dropped frames. Turned off the audio and a "Test" capture and
>> still there are dropped frames. I've end tasked everything that is in
>> XP Pro's Task Manager as to see only the bare minimum running and
>> even unplugged the NIC cable and there are still dropped frames.
>>
>> Since the source is a DVR, I can start and end the capture in the
>> exact same place. So in a ten minute capture there could be 10
>> dropped frames, but the next time (not changing any settings) there
>> could be 15 dropped frames. But one thing that always doesn't
>> changes, a dropped frame at 3 minutes and 20 seconds.
>>
>> Does anyone know why 3:20 would be some magical spot for a dropped
>> frame on every capture?
>
> Could it be the complexity of the video at the 3:20 point in the show?

I doubt that (more below).

> Try capturing only that segment of video. Plus minus a minute and see
> what happens. Do this two or three times and see if the dropped frames
> occur in the same place.

Here is some background on my setup. I have the DVR connected to my A/V
receiver and one of the free S-Video out jacks (along with the L and R
audio) on the back of the A/V receiver connected to the head-in on the
AIW 9800 Pro card (using the v5.1 Cats).

If I switch to the radio tuner on the A/V receiver, I see in VirtualDub
a black screen and hear the AM station audio through the PC speakers. I
can record the black screen with AM audio and get a dropped frame at
3:20. Does not matter if it is a test capture or a real capture.

I also moved the DVR and connected it directly to the head-in on the AIW
9800 Pro card and I get a dropped frame at 3:20. So it seems as though
it has nothing to do with the A/V receiver as a go-between.

Going one step further, I recorded snow from the AIW tuner with an
unplugged antenna and get a dropped frame at 3:20.

It doesn't seem to really matter what the source is, whether it has
content or not, I always get a dropped frame at 3:20.

If I use the ATI-TV (v9.03) software to capture, according to the record
dialog, there are no dropped frames. However, the frame counter in the
ATI-TV software might not be reporting dropped frames accurately. I also
don't like the ATI-TV software as the highest resolution allowed is
704x480 and I would prefer to capture at 720x480.

Using the DVR, I captured the same four minutes of video three different
times. The first time there was seven dropped frames. The second time
there was one dropped frame. The third time there was two dropped
frames. In all cases, there was a dropped frame at 3:20. I shifted the
capture up by one minute and had similar results.

I've gone over the VirtualDub settings (tried both v1.5.10 (stable) and
v1.6.5 (experimental)) and don't see anything I might have configured
wrong or missed.

To be sure, here is what I set in VirtualDub v1.6.5 Capture menus:

Device.............: Microsoft WDM Image Capture (Win32) (VFW)

Video..............: Overlay

Video/Format.......: 720x480 (YUY2)

Video/Source.......: ATI Rage Theater Video Capture (S-Video source)

Video/Compression..: Huffy v2.20, Predict Gradient (YUY2)

Video/Custom format: 720x480, YUY2 - YUV 4:2:2 Interleaved

Audio..............: Enable Audio Capture

Audio/Peak Meter...: Enabled (I use Windows Mixer to set -6dB (prevents
crackle on peaks))

Audio/Raw Format...: PCM: 44100Hz, Stereo, 16-bit

Audio/Compression..: No Compression (PCM)

Capture/Settings...: Frame Rate 29.9697

Capture/Timing.....: Tick next to "Drop if... too close" and "Insert
null... too far apart"

Resync mode: Sync audio to video by resampling
audio faster or slower

Capture............: Hide display on capture

Beyond the mystery spot of 3:20, could I have some setting set
incorrectly or not at all?

I finished a one hour capture a few minutes ago and there were 50
dropped frames. Would 50 dropped frames in one hour be considered
normal?

I also used VirtualDub benchmark tool to test the capture drive. There
are two tests, one for dropped frames and the other to test the speed of
the capture drive. With a setting of 720x480x16 @30fps and 10,000
frames, and a setting of 500MB test size, the "Vidcap Disk Performance
Test" results (respectively):

Frame..............: 10000 (333.4 s)

Dropped Frames.....: 0 (0.0%)

Longest Burst Drop.: 0 (0 ms)

Most Buffers In Use: 6/50

----

Sustained Read.....: 798752KB/s

Sustained Write....: 36984KB/s

Obviously, this is not a very good benchmarking tool if it reports the
"Sustained Read" speed of 780MB/s. :)  What I find interesting is the
"Most Buffers In Use" of six. There is a Disk I/O option under Capture
and it has the following settings:

Chunk Size.........: 512K

Chunks In Buffer...: 2

The "Disable Windows Write Buffering" is ticked. I didn't find any
information about this option or whether it coincides with the six
buffers used in the Benchmarking tool or that it should be adjusted
accordingly.

I appreciate your reply.

--

Tom
April 8, 2005 11:27:37 AM

Archived from groups: rec.video.desktop (More info?)

Richard Crowley <rcrowley7@xprt.net> wrote in
news:115c730f56nga6a@corp.supernews.com thusly:

> Is it really dropping the *frame* at 3:20, or is it dropping the
> *timecode* at that frame? Any chance that you have tape that was shot
> with "dropframe timecode"?

I don't know how to tell the difference, but I think that doesn't apply
in this case. I can only say that the source is a Digital Video Recorder
[DVR] (no digital out, only S-Video). But the source can be anything and
the same thing always happens in the same spot.

Just a few minutes ago, I capture a black screen with VirtualDub v1.6.5
and this is the results:

Frames captured......: 6096

Total Time...........: 3:23

Time Left............: 5:49:53

Total File Size......: 1039.0MB

Disk Space Free......: 104.70GB

CPU Usage............: 7%

[Video]

Size.................: 1004.6MB

Average Rate.........: 29.96028 fps

Data Rate............: 5057KB/s

Compression..........: 4.0:1

Avg Frame Size.......: 172812

Frames Dropped.......: 2

[Audio]

Size.................: 34.3MB

Relative Rate........: 44097.21Hz

Data Rate............: 173KB/s

Compression..........: 1.0:1

VT Adjust............: +0 ms

Resample.............: -0.001 s.t.

Latency..............: 84 ms

I don't know what all of the above means. I listed the settings that I
used in VirtualDub in my reply to "DanR" (here is a direct link, just
double-click):

<Xns9631F415AB50BTominvalidcom@news.supernews.com>

Why it drops a frame at 3:20 every time is a complete mystery to me. All
I know is if I can capture to 3:10 without a prior frame drop, I can do
a NASA style countdown to 3:20 and see "Frames Dropped" go from zero to
one. :) 

I appreciate your reply.

--

Tom
Anonymous
April 8, 2005 10:22:12 PM

Archived from groups: rec.video.desktop (More info?)

In article <Xns96324B007B93Tominvalidcom@news.supernews.com>,
Tom@invalid.com says...
> Why it drops a frame at 3:20 every time is a complete mystery to me. All
> I know is if I can capture to 3:10 without a prior frame drop, I can do
> a NASA style countdown to 3:20 and see "Frames Dropped" go from zero to
> one. :) 
>
> I appreciate your reply.
>
> --
>
> Tom
>

It does seem like it is happening as you hit the 1024 mark. Do you also
drop a frame around 6:40?
--
_________________________
Chris Phillipo - Cape Breton, Nova Scotia
http://www.ramsays-online.com
April 10, 2005 3:25:52 AM

Archived from groups: rec.video.desktop (More info?)

Chris Phillipo <cphillipo@ramsays-online.com> wrote in
news:MPG.1cc0a3fb841cfbbd98a979@news.eastlink.ca thusly:

> In article <Xns96324B007B93Tominvalidcom@news.supernews.com>,
> Tom@invalid.com says...
>> Why it drops a frame at 3:20 every time is a complete mystery to me.
>> All I know is if I can capture to 3:10 without a prior frame drop, I
>> can do a NASA style countdown to 3:20 and see "Frames Dropped" go
>> from zero to one. :) 
>>
>> I appreciate your reply.
>
> It does seem like it is happening as you hit the 1024 mark. Do you
> also drop a frame around 6:40?

It wasn't until you mentioned the above that I realized that it's every
100 seconds. So, I get a dropped frame at:

1:40
3:20
5:00
6:40
8:20
10:00

And it continues in the same pattern until I stop the capture. Probably
the reason I didn't notice it before was the other random dropped
frame(s) that can occur.

What do you think this means?

Thanks for your continued interest.

--

Tom
Anonymous
April 10, 2005 10:37:38 AM

Archived from groups: rec.video.desktop (More info?)

On Thu, 07 Apr 2005 21:01:16 -0000, Tom <Tom@invalid.com> wrote:

>
>Hi,
>
>I'm trying to capture analog video with a AIW9800 and a Audigy2 sound
>card from the S-Video out on a DVR with VirtualDub. The problem is I'm
>getting random dropped frames with the exception of one dropped frame
>always at 3 minutes and 20 seconds. I'm capturing using AVI Huffy v2.20
>at 720x480 and PCM audio at 44.1KHz.
>
>Overall the captures work, but it would be nice to not to see any or as
>many, dropped frames. I've tried just about everything I can think of to
>reduce dropped frames, including a capture at 160x120 with 8KHz mono
>audio which still produced dropped frames.
>
>I turned off 'add NULL' frames and 'Drop frames when to close' in the
>Timing Options and while there were no longer any dropped frames, the
>sound after a short while was out of sync.
>
>The system is a 3.0GHz P4 and the capture drive is a NTFS 250GB drive
>that is empty and sits on its own Promise 133 controller. I've disable
>the audio capture in VirtualDub, still dropped frames. I've done a
>VirtualDub "Test" capture (doesn't involve the hard drive), still
>dropped frames. Turned off the audio and a "Test" capture and still
>there are dropped frames. I've end tasked everything that is in XP Pro's
>Task Manager as to see only the bare minimum running and even unplugged
>the NIC cable and there are still dropped frames.
>
>Since the source is a DVR, I can start and end the capture in the exact
>same place. So in a ten minute capture there could be 10 dropped frames,
>but the next time (not changing any settings) there could be 15 dropped
>frames. But one thing that always doesn't changes, a dropped frame at 3
>minutes and 20 seconds.
>
>Does anyone know why 3:20 would be some magical spot for a dropped frame
>on every capture?


I'd bet the problem is the Creative soundcard. The sample rate of the
card is not exactly 44.1 kHz. I had the same problem with an older AIW
card. The older software didn't drop frames when out of sync, so there
was a huge synch problem. We used to call it the "Kung Fu Effect."One
possible fix is to capture audio at 48 kHz, and then convert to 44.1
kHz with a good audio editor afterwards. Myself, I bought a Canopus
ADVC-100. I plugged it in and it worked. Why can't other video
hardware for a PC work this well?
April 11, 2005 11:19:14 PM

Archived from groups: rec.video.desktop (More info?)

Bunghole <none@bunghole.com> wrote in
news:750i51h5u7d4u9eobv9usrfnrivk3j0il3@4ax.com thusly:

>>Does anyone know why 3:20 would be some magical spot for a dropped
>>frame on every capture?
>
> I'd bet the problem is the Creative soundcard. The sample rate of the
> card is not exactly 44.1 kHz.

Ah, but is it suppose to be? I always thought the 44.1KHz figure was
always a small round-up.

> I had the same problem with an older AIW card. The older software
> didn't drop frames when out of sync, so there was a huge synch
> problem. We used to call it the "Kung Fu Effect.

I played around with VirtualDubs' Timing (sync) options. I turned off
both "Drop if... too close" and "Insert null... too far apart", with the
latter making the most difference. I also had the 'resample audio' radio
button selected to make up for the differences. So, while there are no
dropped frames, the results is the same effect as you described (with
the audio ahead of the video) despite the radio button setting.

> "One possible fix is to capture audio at 48 kHz, and then convert to
> 44.1 kHz with a good audio editor afterwards.

Actually, I should be doing all the audio recording at 48KHz, since the
end-goal is to put all of this on DVD. Although, the audio encoder in
TMPGEnc does a proper job of upsampling. :) 

> Myself, I bought a Canopus ADVC-100. I plugged it in and it worked.
> Why can't other video hardware for a PC work this well?

One reason for that could be the padding that's done inside the Canopus
ADVC-100, so you shouldn't see any dropped frames. Like you, I don't
notice any particular glitch during playback. Unlike you, I know there
are dropped frames. :) 

I've also considered a Canopus ADVC-100 (or the like) device. I like the
idea of putting it near the source and have it deliver the ones and
zeros through a single cable with no outside interference. I'd just run
it into the Audigy2 card and be done with it. Not sure how long of a
Firewire cable you can have. I think its longer than USB.

--

Tom
!