For some reason I can't seem to record an AVI without ultimately dropping lots of frames. I have a Pentium II 300 with 160MB ram. I've tried every codec available and even uncompressed (though I can't really use uncompressed for my purposes anyway, not enough space). What settings does everybody use when recording to AVI? I'm trying to record at 352x288, 15-bit color, 30fps, 16-bit sound, 44.1khz. I drop 30%-90+% of the frames depending on the codec I try. Anyody know what the problem could be?

-- Azrael (afn04314@afn.org), April 19, 2000

Answers

Make sure you have the latest bus mastering drivers for you mother board. Make sure DMA is enabled for you hard drive. Make sure the hard drive your using is a master not a slave. Make sure your hard drive is fast enough.

Good luck.

-- Michael S. Gilmore (mgilmore@san.rr.com), April 20, 2000.

Speed is the answer, moving the data through the buss, the higher the resolution, stereo 44.1 khz, all those bits going through slow buss lines to hard drives that are not fast enough. Editing is usually done on very fast video drives that can handle the throughput. Media has some lower price video array drives that work very well. Some of the new 7200 RPM drives may do better, but the buss can still choke the system.

-- Butch Rupright (Lrupri57@aol.com), April 20, 2000.

Try using BTYUV color instead of 15-bit, you might also try lowering the framerate to 29.976 (w/ WinTV, if I capture at 30FPS, it captures at 30.030FPS, or something close to that). Also, defragmenting your HD can help too.

-- Mr.Ian Roswell (cyberlien51@juno.com), April 20, 2000.

You are using a PAL screen format. As such the proper video bit rate for PAL should be 25 fps, not 30. With AVI formats and even small frame captures you will need a relatively fast I/O disk transfer. But reducing the video bit rate to 25 might help a bit. Plus it will then meet the PAL parameters. PAL format is 352x288 @ 25 FPS and NTSC is 352x240 @ 29.97 FPS. Note this is probably not the cause of your dropped frames.( I just thought it was curious that you would be capturing with a PAL frame size and different VBR) Most likely the problem is your hard drive system. Uncompressed AVI at PAL default frame sizes will mean about 5 Meg per second file transfer. That's about the limit of an older IDE 5400 IBM drive. AND if you are using the same drive as the system or program drive then you might be beyond it's limit. The new Ultra 66 drives can get you up to 10 or more MB/s without problems (if you have an Ultra 66 controller).

-- Rich (richa@home.com), April 21, 2000.

Azrael was probably capturing in PAL @ 29.97fps because the capture card might not support an NTSC width (my capture card can capture 320x240, then the next resolution is 352x288, and a lot of other odd resolutions). When I want to do a quick capture, I use PAL @29.97fps and then encode it to NTSC/VCD with Panasonic MPEG Encoder. That resizes the picture so that it is normal NTSC instead of stretching the 320 resolution to 352. Since the height is stretched to 288 during capture, resizing the height to 240 is just making it normal NTSC. If you captured in 25fps and then encoded to NTSC, the audio and video would be off sync.

-- Mr.Ian Roswell (cyberlien51@juno.com), April 21, 2000.

I have a feeling that you have a slow hard drive and either DMA is not on or you don't have it.

I ran into similar problems. The solution (to avoid dropped frames) is to capture at 10 fps. I know its slow but with a slow hard drive that's the best you can do. Then encode later to the proper rate.

Your video will be ok with no jerkiness.

Gregg

-- Gregg J. Emans (css123@mindspring.com), February 04, 2001.