Audio and video choppy by the end of a longer capture

[anhel96]

I have captured a 30 minutes video into one file. By the beginning of the movie both video and audio are perfect. A little bit over the middle of the move the audio becomes very choppy and it sound like it is playing in double speed. It looks like the video is trying to catch up and it seems to play in almost 2x as well. This is happening every time I import a video. I think it is only when I capture longer sequences. If I capture a small sequence everything is fine.
The reason I capture all of it is that it is easier to capture a complete tape and then split it in edit mode.
Is this maybe not possible? Do I need to capture smaller sections?
What am I doing wrong?

Thanks for any help!

[TDK1044]

Capture duration shouldn't be a problem if all unnecessary background programs are disabled and your system can handle your capture settings. I've captured 90 minutes of footage as one file with no problems. Are you capturing an AVI file or MPEG2? Is your audio LPCM or MPEG?

[DVDDoug]

It sounds like a corrupt video file.

Please tell us something about your file format, and how you captured it. The Read This First... post at the top of the forum tells you what we need to know in order to help you.

[anhel96]

I followed the Recommended Procedure at teh top of this forum.
I don't think it's a corrupt video file, because all files I import in Ulead becomes like this. When I use the simple MS Movie Maker there are no problems like this.
And also when I select to capture only a section that is corrupt in the large file it is working OK.

Do I have any settings wrong? Not enough memory or PC performance etc?

I am capturing to MPEG2. I believe I set the audio format to Dolby Digital.

[Ken Berry]

That explains it. Your computer specs don't look too bad, but I would guess that they are just on the low side of a computer capable of capturing digital video in mpeg-2 format. It is a big ask if you are capturing from a digital mini DV camcorder to expect your computer not only to capture but at the same time convert from the native DV format to mpeg-2 AND also convert the audio format as well. After a while, the computer falls behind in the race and the incoming digital signal fills up a buffer (called the transcode buffer because the computer is trying to transcode from DV to mpeg-2). When the buffer is totally full, the computer has to pause while it processes some of the data to make space for more incoming signal. The result is choppy capture.

There are several options. First, you should as far as possible be following the Recommended Procedures to the letter. I know they refer to capturing mpeg-2. But they are also predicated on capturing from a DV camera in native DV format, doing your editing in that, and only then producing a DVD-compatible mpeg-2 file. This step by step approach imposes far less demands on the computer. And to capture in DV, you need to do so with Firewire, which may necessitate your installing a Firewire card on your computer if it does not already have one. A mini-DV camera will have a small 4-pin Firewire port.

An alternative would be to purchase a capturing device which has hardware included in it to transcode from the incoming signal to mpeg-2. In other words, the device does the transcoding, not the computer -- so there is no stress involved.

The third alternative, of course, is to capture in shorter chunks.

I should perhaps add that your mention of Windows Movie Maker is in these circumstances a bit like comparing apples with oranges. WMM cannot capture in mpeg-2. It can only do it in DV format (preferred) or Windows media format (highly compressed, difficult to edit). Neither imposes any burden on the computer. And it just emphasises my point that it is better to be capturing in DV format.

Moreover, if you do so, you can use the split by scene feature which is not available during capture of mpeg-2 (only available, as you are aware, after capture with mpeg-2).

[anhel96]

Thanks for you reply. I will try any of your suggestions.
However AVI takes a huge amount of space on the HD.

If it is my computer that is on the low side, what PC configuration is preferred if I want to proceed with the process I described by capturing in MPEG2 and Dolby?

Do I need one of the latest processors like Intel Core 2 ViiV etc, faster bus and graphics card, more memory etc?

Thanks

[Ken Berry]

Admittedly, DV/AVI takes up a fair amount of space (13Gb per hour). Uncompressed AVI takes a lot more (around 65GB/hour). But I am afraid that is the nature of the beast. Good quality + (relatively) hassle-free = capturing/editing DV.

I have a vanilla P4 3.0 with HT processor and 2 GB RAM (see my full set-up by pressing my System button below). And that manages to capture mpeg-2 from a DV source just fine. But I hasten to add I have only done this in the past as an experiment. (I have, however, captured long stretches of analogue video as mpeg-2 using my internal TV capture card.)

The fact is that HDDs have dropped enormously in price in recent years. A month or so ago I bought a 400GB drive for A$250 (about US$175) and I daresay in other countries they may even be cheaper. It would certainly be cheaper, in my view, to add a larger HDD to your current set up and capture and edit in DV, than it would be to upgrade your whole system.

If however you are looking for an excuse to get yourself a more powerful computer, then this could be a good one!