Frame Drop - Unable to Eliminate

[Necromancyr]

The Problem:
Whenever audio is being recorded - AND SYNCED to the video -
a dropped frame approx. every 10 seconds of capturing occurs.

Tests & Observations:
- All below were done both w/a motion stream (VHS tape), and with a blue screen coming from a VCR (tested both with composite and TV tuner in).
- Captured w/out audio and got no frame drops.
- Captured at 80x60 resolution, get frame drops as long as audio is being captured and synced.
- Switched out Sound card for a ISA SoundBlaster 16 - still dropped frames when capturing audio at about the same rate.
- In Vdub, compatibility mode works fine w/no dropped frames but results are less then stellar.
- Capturing with timing off results in no drops, but DRASTICALLY out of sync audio.
- In Vdub, the frame rate never settles to one value when the timing is on. It jumps around alot - I don't know it this is because of the dropped frames or what. It does settle w/out timing and in compat mode.

System:
Celeron 800
Abit BX133 MB
512mb memory
5400 ATA66 HDD (16mb/second)
ALS4000 Sound Card/SB16 ISA Card
PCTV Pro (Pinnacle)
GeForce2 Pro
WinXP (VfW Driver :/)

So...I'm certain it's not the data rate because of the tests I've done. But after swapping out the sound card I'm rather stumped. Any ideas would be appreciated.[/b]

[mijman]

I think one possible problem could be your 5400 rpm hard drive. You might not be able to save your data fast enough to deal with the incoming stream. Most capturers swear by the 7800 speed. I know I do. That extra 2400 rpms really makes a difference, and it might for you too.

[Necromancyr]

It's NOT the datarate. There is no way that an 80x60 capture using mjpeg cranked down to low quality so the datarate is like 27kb/second (and using the lowest audio settings I can) is maxing out the datarate.

And the HDD is coming up as 16mb/sec in AuxSetup - and I've never even come close to that.

[sommersby]

1 dropped frame every 10 seconds is nothing! If you are capturing at 30 frames Per/sec that works out to one frame for every 300 captured which is like .3 percent, and you are always going to drop frames when locking the audio to video. How do your videos come out? Does it drop this amount at any bitrate or resolution?

[Necromancyr]

(can we tell I'm at work and have alot of downtime? )

It happens at any resolution - as long as the sound is being captures and synced to the vide. 6-10 a minute is a bit much for me...I would LOVE to get it a big lower is possible (1-2 per 1000 seems to be a decent number from what I've been reading).

[Allan55]

Hi,

I'm a newbie plus a few months but from what I've seen here and elsewhere, capturing video thru one device and sound thru another can cause this because their capture frequecy isn't exactly matched. Generally an occasional drop video frame isn't noticed but a glitch in the sound is like a scratch on an old LP (noisy) so capture software tends to drop an occasional frame to keep audio and video syncronized.

[shochan]

is DMA enabled for your drive?

[stanwebber]

you got one dog of a soundcard. isa doesn't necessarily equate to clock instability, but pci cards are monotonously consistent

[Necromancyr]

Any suggestions for a soundcard without this issue?